Feast or Famine: The Dietery Role of Rabdotus Species Snails in Central Texas

FEAST OR FAMINE: THE DIETARY ROLE OF RABDOTUS SPECIES SNAILS IN

PREHISTORIC CENTRAL TEXAS

APPROVED BY SUPERVISING COMMITTEE:

________________________________________ Robert J. Hard, Chair

________________________________________ Laura J. Levi

________________________________________ Steve A. Tomka

Accepted: ________________________________________ Dean of Graduate Studies

ANDREW F. MALOF, B.A.

THESIS Presented to the Graduate Faculty of

The University of Texas at San Antonio in Partial Fulfillment of the Requirements

for the Degree of

MASTER OF ARTS IN ANTHROPOLOGY

THE UNIVERSITY OF TEXAS AT SAN ANTONIO

College of Liberal and Fine Arts Department of Anthropology

December 2001

ACKNOWLEDGMENTS

This project was conceived in 1995 while assisting University of Texas at Austin Graduate

Student John Voltin with test-level excavations at site 41BL116, when I was struck by the

quantity and diversity of the snails present. In 1998 John graciously granted permission for

my use of site data to pursue my research interests. It was at this time that J. L. “Michael”

Williams began expanding a single 1 x 1 m test pit into a more comprehensive block

excavation, creating momentum that was instrumental towards maintaining meaningful

levels of investigation at the site. With the enthusiastic cooperation and assistance of both

her and Christine Gauger a comprehensive data recovery program was initiated. Numerous

volunteers have assisted throughout the past three years, most notably Bonnie Shanks,

Allison Radke, Dannie Malof, Carol Macauley, George Thomas, and Steve Davis. Mr.

Tommy Blanton of the nearby Peaceable Kingdom has provided logistical support on many

occasions, and of extreme value, has placed a priority on monitoring the site for thieves and

trespassers. A special debt of gratitude is owed to Mr. Jim Bowmer, whose unqualified

support and unbounded interest regarding the information contained within his property has

provided us the opportunity to learn and grow both archaeologically and personally. Mr.

Daniel Prikryl provided aid in the form of lengthy discussions and personal support. Mr.

Kenneth Brown provided valuable assistance and advice as well, especially as I began to

grapple with the nuances of snail identification. I of course would like to thank my

committee members, Dr. Robert Hard, Dr. Laura Levi, and Dr. Steve Tomka. Their various

strengths and interests provided me with tools and insights that have made this thesis both a

challenge to prepare and a joy to finish. This list would not be complete without

acknowledging the late Mr. Bruce Nightengale. He provided opportunities I never

expected, and taught me without letting me know he was doing so. Thanks Bruce. And

finally, my son Jacob, who still shakes his head in wonderment at the thought of counting

all those snails, and my parents, who, in many more ways than one, made this possible.

December, 2001

Andrew F. Malof, M.A. The University of Texas at San Antonio, 2001

Supervising Professor: Robert J. Hard

Snails are a common element in many Central Texas archaeological sites. Members of the

Rabdotus family are often assumed to be present due to a role in the subsistence strategies

of local inhabitants, however, little work has been specifically designed towards clarifying

and supporting this contention. Concepts of optimal foraging theory provide a means by

which the role of these snails can be explored through examining balances of energy

required for organisms to maintain reproductive potential. As human use and

understanding of energy is the focus of the theoretical approach, a history of its role in

anthropological thought is presented, thus placing the use of optimal foraging concepts in

perspective. The presence of snails, meanwhile, has certainly not gone unnoticed by

archaeologists, and they have been used for a variety of analytical purposes. Understanding

these uses allows a more thoughtful approach to future studies. Snails have limited

distributions, and Rabdotus are no exception. Recognizing their environmental parameters

provides an opportunity to more closely link their presence to various aspects of human

behavior, especially when placed within a larger, comparative context. Assumptions of

snail consumption are an insufficient supportive mechanism, and empirical, quantitative

means of discerning signatures of human use are necessary. A step-by-step process for

differentiating between naturally occurring and culturally modified assemblages has been

established, and can be used anywhere Rabdotus snails are present in statistically valid

numbers. If snails are found to have a different population structure within archaeological

sites, human consumption is not yet strongly supported. The nutritional content of one

species of Rabdotus is therefore presented, which when combined with experimental

gathering data, allows the snail to be ranked with other possible food sources. This in turn

creates potential for additional insight into of aspects of social organization, particularly

those that can be associated with subsistence level activities. By more clearly

understanding one particular type of behavior, a greater depth of general knowledge is

obtained.

TABLE OF CONTENTS

Acknowledgments ..........................................................................................................iii Abstract ..........................................................................................................................v List of Figures.................................................................................................................viii List of Tables..................................................................................................................x Chapter 1. Introduction..................................................................................................1 Chapter 2. A Short History of Anthropological Studies of Energy...............................6 Chapter 3. Texas Snails .................................................................................................25 Chapter 4. Defining the Study Area ..............................................................................36 Chapter 5. An Exercise in Model Construction.............................................................52 Chapter 6. Quantifying Snail Populations .....................................................................62 Chapter 7. Return Rates of Snails..................................................................................82 Chapter 8. Conclusions..................................................................................................103 References Cited.............................................................................................................118 Vita

LIST OF FIGURES Figure 1. Location of site 41BL116 in Central Texas ...................................................37 Figure 2. Comparing adult and juvenile Rabdotus. Numbers 1-5 are explained in text. Numbers 6 and 7 illustrate measurement points for width (diameter) and height, respectively. Scale in cm. ...........................................69 Figure 3. Comparing height and width between adults and juveniles from 315 shells sorted out of 1/4 inch screen from the BFL2 collection........................73 Figure 4. Control BFL2 sample approximating a 50% natural death assemblage. Note that the number of juveniles was adjusted from 173 to 142 in order to create a true 50% comparative ratio. The total BFL2 sample is compared below...............................................................................................74 Figure 5. Control BFL2 sample approximating a 50% natural death assemblage, with the combined mean of the adult and juvenile populations added............75 Figure 6. Control BFL2 sample approximating a 50% natural death assemblage with actual death assemblage from 1/4 inch screen sort added and compared to the combined mean of the adult and juvenile populations (TotalMean). ................................................................................75 Figure 7. The 50/50 Site Sample (Modeled Natural Population), comparing adult, juvenile, and total mean width-to-height ratios. ....................................76 Figure 8. The 50/50 Site Sample (MNP) as in Figure 7, with the 5% Site Sample representing the Actual Site Population (ASP) added........................77 Figure 9. Comparing an MNP (adult, juvenile, and 50% test) with the actual assemblage of live snails from the BFL1 collection. ............................78 Figure 10. Comparing an MNP (adult, juvenile, and 50% test) with the actual assemblage of shells from the Off-Site ST collection ..........................79 Figure 11. Comparing an MNP (adult, juvenile, and 50% test) with the actual assemblage of snail shells from the Off-Site2 collection......................81 Figure 12. Linear regression and best fit line comparing numbers of Rabdotus to numbers of mussels per level. .....................................................94 Figure 13. Linear regression and best fit line comparing time spent in each patch and the number of snails collected. ...........................................107

Figure 14. Linear regression and best fit line comparing time spent in each patch and the number of snails collected. ...........................................108 Figure 15. Linear regression and best fit line comparing time spent in each patch and the number of snails collected per square meter (density). ..............................................................................109 Figure 16. Linear regression and best fit line comparing the time spent in each patch and the number of snails collected ............................................109

LIST OF TABLES Table 1. Comparing collection times, rates, and returns for ten patches. ......................86 Table 2. Results of a nutritional analysis on 200 gm of Rabdotus mooreanus snail meat ......................................................................87 Table 3. Comparing the nutritional value of Rabdotus mooreanus snails with other mollusks and generalized food types. .............................................88 Table 4. RDA, time for acquisition, and percent per 100 gm meat for Rabdotus mooreanus........................................................................................89 Table 5. Comparisons of energy return rates of various foods. From Kelly (1995:Table 3-3) ...........................................................................90 Table 6. Comparing the nutritional and caloric returns for five potential food sources ......................................................................................99 Table 7. Gross rates of return for ten patches collected for Rabdotus species snails ....................................................................................106

CHAPTER 1.

INTRODUCTION

Snails are a common element in many archaeological sites, and in south Texas, at

least, might be termed ubiquitous (Brown 1999:213). The presence of these mollusks has

received varying levels of attention over the past 40 years, with some authors attempting to

incorporate them into interpretive schemes and others largely ignoring them.

Snails are useful for a variety of analytical purposes. They have been utilized in

order to achieve a better understanding of past environments through evaluating the

environmental niche preferences represented by recovered shells. They have also been

used to date sites and occupation zones both absolutely, through adjusted AMS techniques,

and relatively, through the use of amino acid racemization rates, a tool useful for

determining the extent of mixed deposits.

Another aspect of snail research has been geared towards the issue of prehistoric

consumption of snails by aboriginal peoples. To some it is self-evident that snails,

(exclusively the members of the Rabdotus family), were consumed. Ethnographic evidence

has shown this to be the case. For some others, it is felt that although in some instances

snails were eaten, in many, if not most cases, the archaeological presence of Rabdotus and

other snails are an artifact of processes not directly associated with human subsistence

patterns. Most prominent in this argument is the concept of the “commensal scavenger,”

which argues that Rabdotus made itself present at human campsites in order to feed off of

the detritus-enriched environment. It has also been demonstrated that natural flood events

can deposit high quantities of snails (shells) in near-alluvial settings in the form of drift

deposits. Many modern snail collections are actually gathered from such accumulations.

Site 41BL116, located in western Bell County on the Edwards Plateau, is a

prehistoric open camp containing Late Archaic through Late Prehistoric diagnostic artifacts.

Radiocarbon dates have placed major occupation zones from between 3100 and 1500 years

before present (BP). Perhaps not unusual, but still striking, are the high numbers of

molluscan animal remains—both freshwater mussels and land and water snails—at the site.

There can be little doubt that the mussels were gathered for consumption as no natural

processes could account for their presence and charred shell is commonly found in direct

association with cooking appliances.

Rabdotus shells are likewise common, and share similar associations; in fact, their

numerical presence can be seen to temporally mirror that of the mussels. This might be

cause to simply state that humans were gathering the snails for consumption and then move

on to other avenues of research. But presenting an assumption as fact does not make it so.

At present, there is no model in place that might allow testing of such a hypothesis.

There are, however, theoretical mechanisms that create the opportunity to construct such a

model. This thesis looks at the question of Rabdotus-based subsistence from an optimal

foraging perspective. One of the tools of optimal foraging models is the ranking of

potential food resources. This leads to greater understanding of food choices made by

humans. An abundant, high ranked resource is gathered in preference of less abundant,

lower ranked food items, and the breadth, or variety, of diet is low. As the more valuable

resources decline in abundance, it is more likely that lower ranked resources will find their

way into the dietary regime, and diet breadth widens.

Rabdotus might conceivably fit in either category, and either would be telling as a

means of understanding past human behavior. Should the snail be high in energetic value

and also easily obtainable, its presence might indicate stable human populations exploiting

an available resource. Should the snail provide a low energy return, yet high quantities

occur within a site or locale, indications would be that human populations were adapting to

a decrease in abundance of higher ranked resources, perhaps due to some form of seasonal

or long term environmental stress.

There are two main issues that must be addressed in order to determine if snails

found in archaeological deposits are the result of human foraging activities or are the result

of some other, natural process. The first involves determining if human snail gathering

might leave distinctive signatures in the archaeological record. Brown (1999:251) asked a

number of questions, the answers to which he suggests can help determine the place of

Rabdotus in archaeological contexts. The first question was “what percentage of juveniles

can be expected a natural death assemblage”; and the second was “what density of recently

dead…Rabdotus shells can be expected to occur in a natural setting?” This project

addresses these first two questions. The most relevant information is in regards to the

percentages of juveniles, which are shown to vary in proportion between “natural” and

archaeological site settings. This allows a quantitative method to be established based on

empirical returns, one that can be replicated in various settings, thus allowing this

conclusion to be potentially supported. The second issue, whether or not snails can be

shown to vary in density between on-site and off-site settings, is also addressed. For one

archaeological site at least, there is a real difference in the numbers of snails found within

the site and the number found directly adjacent to it.

The second issue lies in understanding the energetic and nutritional value of

Rabdotus. Although showing that population structures are distinctly different within

cultural deposits, snails must still be justified as a food source. To this end, the nutritional

value of at least one species of Rabdotus is presented. This allows the snail to be compared

meaningfully with other food items in regards to relative caloric and food value, and more

significantly, when combined with experimental gathering data, the amount of energy

expended in procuring that nutrition. From such actualistic studies the net energy return of

snails can be determined, allowing the principles of optimal foraging theory to be applied,

thereby testing the assumption that Rabdotus is a reasonable source of energy for

subsistence level foragers. This study establishes that although not a very efficient source

of energy, Rabdotus does provide a sufficient return to justify its acquisition within a broad-

based diet. Then, by looking at the macronutrient composition of the snails, refinements to

the diet-breadth model are proffered that allow for a multi-tiered approach to further

understanding the dietary role of snails and other mollusks in Late Archaic Central Texas.

What follows begins by an examination of energy studies in anthropological

thought. Chapter 2 reviews the theoretical trends that have led to optimal foraging theory,

in order to attain a better understanding of its uses, strengths, and weaknesses. Theory

operating in a vacuum loses it explanatory power, so it is necessary to understand the

underpinnings before attempting to invoke the paradigm.

Just as the theoretical position must be supported, so must the subject of study.

Snails can provide a wide range of useful information, and by becoming at least passingly

familiar with possible uses, a researcher can make better informed decisions as to how data

recovery might proceed. It is in this third chapter that the optimal foraging model as

applied to snails is more fully developed, setting up the procedural elements that will be

utilized in later sections.

Chapter 4 introduces site 41BL116 and places it within localized environmental

parameters. Central Texas is not only an ecological zone, but a cultural area as well.

Various approaches to describing and understanding the interactions between culture and

environment that have resulted in what is termed Central Texas are presented, thus placing

the study area within localized contexts.

Chapter 5 expands the ecological discussion and provides an opportunity to explore

environmental data at a scale that should help clarify some of the modeled choices that will

be based on optimization and evolutionary ecology, the overarching system in which

optimal foraging models reside. Although testing a full scale regional model is beyond the

scope of this paper, it is useful to apply some of the modeling concepts to the study area,

and so demonstrate the foraging aspect of these human lives from within a broader context.

Chapter 6 returns to empiricism and actualistic studies. These are often referred to

as middle range applications. The concept of middle range theory is explored, and

determined to be a relevant and justifiable perspective from which to approach the research

objectives. Rabdotus species snails were gathered experimentally over a period of several

months in the spring of 2001. This data provides the backbone for the thesis, from which

on-site and off-site population structures are compared. A specific and detailed

methodology is presented that shows that the Rabdotus assemblage from 41BL116 is

significantly and demonstrably differently structured than naturally occurring populations.

It also shows that live snails, gathered experimentally while mimicking expected aboriginal

behavior, resulted in an assemblage statistically indistinguishable from the site sample.

If Rabdotus has ever been quantified as to food value, the source is obscure or non-

published. Chapter 7 presents the results of a detailed food value analysis on

experimentally gathered Rabdotus species snails. This information, coupled with

experimental gathering data, allows net energy returns to be calculated. Rabdotus can then

be placed on both an absolute energy scale of return rates against which other potential food

sources may be measured, and on a relative scale, one that factors in the macronutrient

content of the snails as well as various environmental and perhaps cultural variables, and so

may affect when and to some extent why snails might enter the diet. A strong correlation

between snails and freshwater mussels is demonstrated, and it is suggested that the two

food items were complementary, allowing foraging decisions to be made that may not be

possible if only one of the items is exploited.

One of the primary complaints against optimal foraging models is that they do not

mirror reality, but rather present an idealized conceptual frame into which the larger picture

is often forced. The common answer to this issue, and the one that is used here, is that this

is not meant to represent absolute reality. Chapter 8 tests some of the assumptions optimal

foraging models place on the data. Diet breadth was addressed in Chapter 7, so it is here

that the patch choice model is examined. Next, the large scale model presented in Chapter

5 receives attention, and some tentative conclusions regarding population size, seasonality

and mobility, and social organization are presented. This is the point where the middle

range theory becomes actualized, linking the empirical data to broader issues of culture and

adaptation.

It is understood that humans act within a myriad of possibilities from which an

infinite number of choices are possible. The model that is presented represents one possible

set of such choices. As such, it is rests firmly within the hypothetico-deductive approach.

The hypothesis is presented (humans ate snails), the research design is established (the

model), and data is gathered. If the hypothesis cannot be supported it is abandoned. If,

however, it is supported, it can be redefined, with additional data gathered to test within a

refined model. Repeated tests may eventually allow the model to be accepted as fact.

The present project is somewhere along the midpoint of this trajectory. Close

associations of snails with other food remains in relatively assured contexts support human

consumption of snails. This thesis brings additional data to a specific perspective, and

ideally sets up a new stage of research. This may be within evolutionary ecology, or might

fall within a different theoretical construct. Regardless, it is hoped it presents data in an

informative and useful way, and that what follows will be of interest to future researchers.

CHAPTER 2.

A SHORT HISTORY OF ANTHROPOLOGICAL STUDIES OF ENERGY

Human use of energy plays an often integral part in interpretations of human

interactions, particularly within the natural world. The systemic nature of the energy cycle

lends itself well to positivist theories of human adaptation strategies, particularly within

foraging or hunter-gatherer contexts.

It is necessary first to define what is meant by energy, and to clarify its importance

in human affairs. The Concise Dictionary of Science defines energy as “the capacity to do

work,” which can be mechanical, electrical, and thermal, among others (Gaynor 1959:173-

174). On a biological level organisms expend energy to accomplish tasks, many of which

involve acquiring this energy to spend. The result is an energy balance, which for life to

sustain itself, must remain positive (Krebs 1994:603). The basis of almost all biological

energy is sunlight. Sunlight is transformed by autotrophs into a usable form (through

photosynthesis) and becomes what has been termed primary production (Kelly 1995:66,

Belovsky 1986). Rates of primary production can be quantified and then used as an index

for heterotrophs (omni- and carnivores), also referred to as secondary production (Kelly

1995:69). The environment becomes both an energy reservoir and an energy conduit. This

process provides a system in which construction of predictive models can be designed to

test foraging strategies.

One such model is based on optimization theory, again originating in the natural

sciences and widely applicable, at least to the community level (Krebs 1994:476).

Optimization has been summarized as the maximization of energy intake (Martin 1983:612)

within a holistic systems approach that is related to Darwinian fitness (Kaplan and Hill

1992:168) in which, once again, energy is the currency (Kelly 1995:101-108).

Energy can be approached from other perspectives. One method involves trying to

understand what may drive social change and has roots in the thermodynamics of Leslie

White (Trigger 1989:290), utilizing concepts of landscape ecology (e.g. Naveh and

Lieberman 1983) and chaos theory (McGlade 1995) within the framework of general

systems theory. Such approaches are potentially valuable, especially when attempting to

understand behavior in terms that transcend archaeological site boundaries (e.g. Ebert 1992,

Dunnel and Dancey 1983, Thomas 1983, Wandsnider 1992, Chang 1992, c.f. Binford

1982).

Early reviews of human interaction with the environment are seen in the works of

such classic writers and historians as Herodotus, Thucydides, Diodorus, Sicilus, and Strabo

(Pallotino 1991:60). Tacitus (AD 98) was another writer and observer of his world, and

from him it is possible to gain insights on the tribal people of Germany during that time.

Although he was writing from an emic perspective (Harris 1968:395), and some of his

information may be less than accurate (Whittaker 1993:283) the approach is one of viewing

behavior as the result of environmental influences.

Tacitus saw the Germans as people who were well adapted to cold, and therefore

could not function well in warm climates, and for the same reason were not suited for long-

term, laborious tasks. They were, however, adept at short-term bursts of high energy,

which to Tacitus explained a seeming predilection towards raiding rather than farming as a

means of subsistence. The cold also induced them to consume large amounts of alcohol

which led to violent councils that nonetheless were an effective means of self-government.

In short, Tacitus observed a group of people that behaved in ways he was not familiar with,

and in trying to understand this variation, utilized the most obvious difference between his

native country and theirs, namely, the climate and resulting environment.

It was during the Enlightenment that a florescence in anthropological thought was

initiated (Harris 1968:8) and numerous socio-evolutionary theories were developed

(Trigger 1989:84). Many of these called upon the classic texts as authorities and an effort

was made to use postivism as a means of understanding the natural world and the place of

humans within it (Harris 1968:1). Rousseau, for instance, in his discourse entitled The

Origin of Inequality (1775), postulated that a variable environment required different

adaptive strategies in dependent on geographic regions that resulted in differentiation in

tool use and led to the intensification of resources. Although his goal was to illuminate an

evolutionary sequence of necessary human development, he also recognized and discussed

how environmental conditions can potentially affect human adaptations.

Montesquieu, in his Spirit of Laws (1748), like Tacitus, looked at climate as a

primary causative factor in human behavior, although unlike Tacitus, felt cold climates

created a more temperate personality. Montesquieu believed cold weather physically

affected cells, and showed experimentally that the cells on the tongue of a sheep contracted

when chilled. Likewise, he postulated that persons in warmer climes required replacement

of body fluids with a like substance (water), while those in colder areas were better suited

for the effects of alcohol, which served to “give motion” to the blood. The German imbiber

then, was acting within reason, while one from Spain was acting immorally. He noted that

warmer climates seemed to be associated with increased reproductive success (fitness), but

this was also an indication of moral weakness. In general, persons from the North were

calmer of temperament and morally superior to those of the south. It is interesting to note

that these conclusions, largely opposite those of Tacitus, correspond with Montesquieu’s

area of origin, as do those of Tacitus’s.

Montesquieu argued that the effects of climate not only influence behavior but also

the institutions by which humans govern themselves. The Arab nations, for instance, have

strong laws regarding consumption of liquor, which Montesquieu saw as proof of his

theories. Climate influences the spread of disease, and laws are enacted to contain them. In

Britain, people are so entirely miserable that they developed an assembly with laws that

spread authority across a wide board, as they could not trust any single person as wholly

unhappy as themselves.

Montesquieu, then, was one of the first to develop a hypothesis based on a certain

level of empiricism that could be used as an explanatory device, as well as be tested

through observation of the immediate natural world. He was pulling energy ever closer to

the realm of heuristics.

It was not much later that Malthus expounded principles that influenced Charles

Darwin and Herbert Spencer, resulting in “the biologization of history” within a framework

of “universal progress” (Harris 1968:35, 107). The core of Mathusian theory lies in the

inequity between geometrically increasing populations subsisting on arithmetically

increasing environmental resources, thus determining population dynamics (Meffe and

Carroll 1994:442). Spencer, seemingly more than Darwin, concentrated on evolutionary

processes in humans, and helped develop what has been termed the “comparative method,”

a direct historical approach that assumed modern populations were very similar to

prehistoric ones at a similar level of development (Harris 1968:150) establishing precedents

that allowed explicit socio-evolutionary models to be devised and accepted.

Morgan, in Ancient Society (1877), elucidated Tylor’s (1871) evolutionary

trajectory from savagery through barbarism to the epitomization of civilization. This

tripartite division can be seen as well in the early eighteenth-century three-age system;

stone, bronze and iron (Trigger 1988:60, Harris 1968:146) and within Montesquieu, who at

an early date separated savages from barbarians (Harris 1968:29). Morgan saw evolution as

a necessary and concomitant aspect of human existence. An implication was that if certain

groups had failed to arrive at the level of civilization, they were somehow deficient. At the

same time, by examining their place on the ladder, a direct view into the past of civilization

was possible.

Subsistence, (and therefore environment) was a driving force of change, especially

among developing savages. Perhaps following Rousseau, Morgan argued that exploitation

of the environment for subsistence purposes led to improvements in technology which

allowed more time, (and mental sophistication), to develop new technologies to better

exploit the environment. It was by controlling the environment that humans became more

fully equipped to develop or discover new technologies that made them more suited to

exploiting the environment, a reciprocal process that lent itself naturally to social

development.

In what has been termed, (perhaps wrongly) a reaction to Morgan, evolutionism,

and the comparative method (Harris 1968:291), the Boasian school of anthropology, in the

first half of the last century, championed the inductive method, and as exemplified by

Alfred Kroeber, largely departed from positivist approaches (Harris 1968:336). Boas

himself did not seem to feel the comparative method and aspects of environmental

determinism were completely without merit, but he did suggest that necessary

methodologies were not in place that would allow productive research emanating from a

broad theoretical perspective (Boas 1940:270-280, 281-289, 290-294, 525-529). A

generation of Boas’s students focused on particular aspects of small-scale societies,

searching for explanatory devices typically grounded within the social group itself, rather

than outside, extra-societal forces (Moore 1997:65-67).

It was not until Leslie White and then Julian Steward that Morgan’s work was

reformulated and the scientific method again became explicit in anthropology (Moore

1997:169, Harris 1968:37), when Leslie White formulated a detailed conceptual analysis of

energy as a determinant factor in human affairs (White 1943, 1959), while Julian Steward

gave evolution a new outlook within the context of a multilinear methodology (Steward

1972). These works helped renew positivist approaches that would lead, among other

things, to the “New Archaeology” of the 1960s (Trigger 1989: 289-290).

Leslie White and Julian Steward were contemporaries, both in age (White was two

years older) and in practice. They were educated in the Boasian school; White under Sapir

(among others) and Steward largely under Kroeber. Both began publishing in the 1930s

and continued through the 1970s, and both espoused a departure from the dominant

relativistic paradigm within which they had been trained. Survey texts often seem to cover

White before Steward (e.g. Harris 1968, Trigger 1989, Moore 1997) and Steward seems to

be cited more frequently in the literature. In short, Steward seems to have had a greater

influence on recent anthropological thought than White.

Both Steward and White were interested in the effects of environment on culture,

with Steward looking at its systemic nature, and White reducing it to its core element,

energy. Because energy is essential for all other natural functions, it is therefore the

element against which all else can be measured. The result is an absolute quantification of

all aspects of the natural world, and this involves culture, as well as the evolution of culture.

White (1943, 1959) was able to produce mathematical formulas that explained how culture

develops, and so was attempting to show that culture is subject to laws that can be proven,

and is therefore universal in nature. This hearkens back to the evolutionary theory of Tylor

and Morgan, and indeed, White explicitly states his indebtedness to them, and denies that

he is practicing any form of neoevolutionism (White 1959:ix).

Steward, meanwhile, describes White’s approach as “universal evolution,” which he

feels is different from the unilinear model of Morgan and Tylor based on its rejection of

specific instances of universal stages in favor of viewing culture as an entity subject to

forces in a general sense, and distinct from his own multilinear approach (Steward

1972:16). Steward’s introduction of the universal evolution concept has been criticized as

arbitrary and irrelevant in that evolutionists can be placed within at least two of his

categories (Harris 1968:642). White, meanwhile, denies that Morgan and Tylor had

unilinear tendencies, stating that they were concerned with culture and not society, and that

“culture, or portions thereof, passed through stages of development” (White 1973:51, italics

in original). It was therefore invalid to state, as Steward did, that the early evolutionists

were trying to force data regarding placement of prehistoric or precivilized people into

categories while ignoring regional variation (Steward 1972:15).

Steward argued that his concept of multilinear evolution was a more realistic way of

understanding culture change and avoided the over-generalizing methods of White

(Steward 1972:28). Where White had completely divorced himself from his formative

influences, Steward was maintaining a middle ground, keeping what he felt were useful

aspects of the relativistic school of historical particularism and applying them to

positivistic, generalizing theories of evolution revolving around environment, an approach

he termed cultural ecology (Steward 1972).

Steward was not looking for universal stages, but rather causes of culture change.

Cultural ecology examines how change is induced by adaptations to the environment, with

humans introducing the reflexive super-organic factor. Although Steward is looking at the

environment as causative, it is not strictly deterministic, as it may be merely a shaping

force. Furthermore, cultural patterns are not genetically derived, and so biological

principles cannot be used to study culture. It is culture itself that explains human society,

and cooperation is as likely as competition. It is through, in part, culture histories that

explanations must be reached, not the biological sciences, and it is through recognizing

levels of integration of individuals and institutions that the evolution of human societies can

be understood.

The environment remains a very important part of this scheme, however, and it is

Steward’s concept of the “cultural core,” the “constellation of features…most closely

related to subsistence…and economic activities” that provides the motive force for cross-

cultural comparisons (Steward 1972:37). Local environments require varying adaptive

technologies that can used as indexes for understanding the differences seen in various

cultures. By understanding the relationship between environment and technology it is

possible to see behavioral patterns which are involved, through the cultural core, in

subsistence and basic economic pursuits and relate these to other aspects of culture. If these

minimally impact the aspect of interest than it is reasonable to look at historical processes,

such as diffusion, as explanatory. If, however, they appear to be of import, then the cultural

core has been approached and is relevant in understanding the question at issue. By using a

holistic, systemic approach, wherein the question of interest is framed appropriately against

various causative factors it is possible to determine whether a generally operative or locally

distinctive process is in play. Cultural evolution is represented, then, through increasingly

complex organizational forms that are nonsequential in nature.

Steward thought it was necessary to distinguish between the culture area concept

and the culture type. The culture area he felt was reductionist in that it was a classificatory

method based on differences that led naturally to a relativistic view of culture. When the

diachronic perspective is added trait relationships become disrupted as the links between

them become irrelevant. The cultural type, however, is represented by core features that are

functionally similar but are not the result of diffusion. When the form-function concept is

included the reflexive nature of the relationship between both is recognized which again

avoids the problem of relativism, an almost unavoidable consequence of looking only at

It is Steward’s reliance on the understanding of particular patterns that White felt

was the downfall of the multilinear approach. Steward could not lay claim to an

evolutionary perspective because he was hopelessly entrapped in an effort of developing

theory that had no utility in explaining “particular features of particular cultures,” an

impossible task given that only broad generalizations are capable of enveloping and

explaining particular situations (White, in Harris 1968:649). What enabled these broad

generalizations for White was the explicit understanding of energy as the prime motive

force in all things natural (White, 1943, 1959, 1973). By following a very systematic

internal logic, White was able to elevate the study of culture to a true science, one he

dubbed “culturology.” Energy is universal, therefore, behavior is a manifestation of energy.

Culture exists to “serve man,” most especially through controlling the external world (e.g.

subsistence). Because this is primary (culture could not exist without food), other purposes

of culture (the “internal,” reaffirming aspects, such as symbolism) can be given secondary

importance. Thus, the human aspects of culture, along with habitats, which are averaged

across the world, can be ignored for the study. What is now relevant is the amount of

energy (E), the technology (T) used to harness it, and the product (P) which results. This

can be expressed E x T = P. Individual strengths and weaknesses can be averaged, and so

factored out, which allows technology to be expressed in terms of efficiency, with any one

technological application (tool) having a rate of efficiency that cannot be improved upon

(100% efficiency). Efficiency (F) can now be substituted for technology in the equation, E

x F = P. Culture, (which serves man), can thus be measured by total productivity (P), This

leads to the first of White’s laws, which states that P varies directly with E, when F is held

constant, and the second law, that P varies with F, if E is held constant, all the while

understanding that both E and F are dynamic and can vary in infinite ways with respect to

each other. The result, however, is that culture progresses when E and/or F increases.

As the purpose of culture is to serve humans, to make life more secure and more

comfortable, human evolution, the “struggle for survival” (White 1943:339), is seen

through culture. Primitive societies had a constant, albeit low supply of energy. For culture

to develop an increase in efficiency was required. Barbarism therefore began with the

advent of agriculture, and to some extent pastoralism, although agriculture, as a more direct

manipulation of the environment, was a more efficient technology. The final stage,

civilization, did not begin until the “fuel revolution,” which was attributed to James Watt

(White 1973:62). This was a huge leap forward in the harnessing of energy, and

precipitated culture rapidly forward.

White did not totally ignore the social aspects of culture. For example, he

acknowledged the argument of the individual as a catalyst for change; that without the great

minds that developed new technologies the development of culture would be decidedly

different. White countered, however, that within the greater scheme of culture, the motives

and intentions−the psychology−of the individual, were irrelevant. Likewise, the institutions

of culture, which were of such central significance to Steward, were realized as being

important in that they tempered the relationships of energy and production, but it was

technology that maintained dominance, with social evolution dependent upon technological

evolution, while recognizing a feedback mechanism existed between the two. A social

system might therefore hinder technological advance to the point where cultural advance

halts. Recalling the formula E x F = P, it would require an increase in energy to invigorate

the system once more.

It is interesting to speculate as to why White, “the dragonslayer of Boasianism”

(Binford 1972:6), seems to have been the loser in the struggle for theoretical supremacy.

The differences between White and Steward were irreconcilable, at least on a personal

level, try as did some to mediate (Harris 1968:651). It is ironic that White had multilinear

tendencies (Harris 1968:643), while Steward was able to describe generalizations that

White could accept as evolutionary (Harris 1968:653). Qualitative differences can be seen

in how they disseminated their ideas. As late as 1959 White was presenting his work as

self-evident fact, using examples from a wide range of disciplines in a manner which often

seemed didactic and tautological. His blatant attacks on the dominant Boasian paradigm of

the time apparently caused him to lose much in the way of general popularity and may well

have negatively affected his professional life (Moore 1997:170), even as he himself realized

that he was not the most popular man in the field (Binford 1972:6). But it is probably his

extreme reductionism that expressed all of human culture in terms of energy management

that was most damning.

The aspect of Steward that White found so annoying, his straddling of the fence

between the two fields of relativism and positivism, is probably his greatest strength.

Steward’s debt to Kroeber and historical particularism is readily apparent. As noted earlier,

he explicitly states he is interested in explaining regularities in patterns that are seen cross-

culturally. He is thus taking the descriptive, inductive methods of Kroeber to the next level,

applying deductive principles in order to determine causative factors for observed variation.

By focusing on likenesses rather than differences the unique cultures of Kroeber are seen to

have similarities that have nothing to do with diffusion or direct historical processes. The

culture types of Steward are based on selected features; particular aspects that are felt to be

of relevance to the problem at hand. The underlying methodology here is clear, and it

parallels that of historical particularism. Although the relativist school would not explicitly

search for general principles, it might well appreciate the formulation of particular laws that

seek to explain specific situations within certain constraints, without attempting to develop

universalities. Steward had also reintroduced the concept of the superorganic, reframing it

against an environment that is not passive, simply allowing or prohibiting events, but active

and at times determinant, actually creating change based on how the organism−the

superorganic structure of culture−adapts to particular environments in particular places.

Steward then, was able to craft an approach to describing and explaining the intricacies of

humans and the environment without broadly alienating the established view nor making

assertions that were so broad as to be always true, and therefore non-explanatory (Steward

1972: 28).

Both Steward and especially White were influential in that they reopened

anthropology as a valid field in which to apply deductive, positivistic approaches to

understanding society and culture change (Moore 1997:179). Theory building was again

possible (Binford 1972:8), especially in archaeology (Trigger 1989:293), and White’s

formulations of energy, technology, and product acting reflexively with other aspects of

culture were recast in material form as Binford’s “technomic,” “sociotechnic,” and

“ideotechnic” artifact classes (Binford 1972a:21-22). The concepts of cultural ecology,

meanwhile, are still broadly accepted (Moore 1997:188) and utilized (e.g. Netting 1986).

Applications such as catchment analysis (Jarman et al. 1972) follow closely on

understanding the relationship of humans and the natural environment. Whether or not

recent schools such as evolutionary archaeology represent a new paradigm (O’Brien and

Holland 1995) or can be seen as emergent methodological advances remains debatable.

What seems clear, though, is that behavioral ecology and optimal foraging theory,

developing out of biology, could not have been applied anthropologicaly without the

contributions of the so-called neo-evolutionists.

So, Steward and White to a large degree set in motion methodologies that would

allow the next generation of anthropologists to proceed with increasingly refined and

detailed theoretical approaches and research designs. The evolutionary perspective

demands such empiricism. But the contribution of the functionalist school cannot be

ignored, especially as expressed through the perspective of Malinowski (Trigger 198:245)

who looked at culture as a way of meeting human needs (Moore 1997:133), in part a

response to biological necessities where social responses have “beneficial consequences”

(Smith and Winterhalder 1992:43). Detailed ethnographic studies were taken to new levels

in works such as Rappaport’s Pigs for the Ancestors (1968) where detailed environmental

data was collected as a means of explaining the function of ritual within certain societies in

New Guinea. Such “particular” bits of information become increasingly vital to later work.

By 1959 it was realized that an increasing interest in environmental studies and

concomitant patterns of settlement was resulting in a renewed emphasis on the processes of

culture, especially as seen within systemic contexts (Trigger 1989:294) leading to the

cultural materialism of Harris, which he deemed to be an overarching perspective that

included cultural ecology as one of its subsets (Harris 1968:658). Such approaches took

shape not only in the realm of the physical world but in the mental as well, with Claude

Lévi-Strauss suggesting that an understanding of how such mental constructs as myths and

kinship terminologies are structured can lead to a universal understanding of basic human

social systems (Leach 1970).

Lewis Binford, meanwhile, was also looking at systems, but with an emphasis on

the functional aspects of environment on human adaptations formulating approaches that

became particularly influential in American archaeology (Trigger 1989:295). Binford

reemphasized the role of technology in human development, and became increasingly

perplexed about the failure of archaeologists to incorporate theoretical designs into their

research and the lack of interest in the potential of archaeology by many anthropologists

(Binford 1972:9-10). His paper “Archaeology as Anthropology,” first published in 1962,

introduced the terms technomic, sociotechnic, and idiotechnic, suggesting that technology

functioned across functional, social, and ideological levels of culture, and systems could be

understood by the construction of testable models based on ethnographic analogy and

comparative ethnography, thus forcefully arguing for a deductive approach towards

understanding the processual, systemic nature of culture (Binford 1972: 17-18). These

explicitly stated aims allowed Binford to use not only his own ethnographic work among

the Nunamiut but the work of others in varying parts of the world, and by drawing on

environmental similarities as expressed in effective temperature, explore such things as

mobility (Binford 1980) and housing, subsistence, and storage (Binford 1990).

Central to such approaches is the concept of “middle range theory” which

approaches the static, material, and non-symbolic aspects of culture to reconstruct history

(Binford 1981b: 23) and can also be viewed as theory of “limited sets of phenomena”

which may be derived from “general sets” (Bettinger 1987:124, 131). By developing

inferences based on physical remains, hypotheses about the people or cultures that

produced them can be tested using theory as a guide to interpretation (Simms 1987:4). The

past cannot be known directly from the artifacts (Kuznar 1996:160), but must be surmised

from and supported by evidence from a multitude of disciplines (Watson 1991:278).

Although it might be argued that middle range theory is limiting, especially in regard to

more generalized theory (Bettinger 1987:131), it has also been stated that such approaches

are the only way to interpret the archaeological record (Ellis 1997:46).

The continuing emphasis on “primitive” people is once more undoubtedly due to a

deterministic evolutionary perspective where human inventiveness was downplayed in

favor of responses to environmental factors (Trigger 1989:296). They also presented a very

appealing lifestyle during times of high anxiety as nuclear weapons proliferated during the

1960s and doubts as to the future of humanity became more focused; hunting (and

gathering) was seen as “the most successful and persistent adaptation man has ever

achieved” (Lee and DeVore 1968:3). Such foragers became idealized as working short

hours with ample time for leisure, thus becoming termed the “original affluent society”

(Lee and DeVore 1968:6, Sahlins 1968:85). An explicitly defined “generalized foraging

model” (Isaac, in Kelly 1995:14) was thus initiated, and became entrenched for a time as

research into hunter-gatherers proliferated, resulting in new data that indicated a range of

diversity that could not be explained in terms of any single approach (Speth 1991:x). For

example, when “work” was redefined to encompass all aspects of subsistence, rather than

just the actual acquisition of resources, an average 15 hour work week suddenly became

well over 40 hours (Kelly 1995:20).

One reaction to the contradictions seen in the material ethnographic record, as well

as a tendency by positivists to ignore issues as such as psychological and ideological

aspects of culture (Trigger 1989:302) was the post-processual school initiated by Hodder

and exemplified by Tilley and Shanks (Kuznar 1996:162) among others. Post-

processualism holds that extreme positivism has limited potential, and that by applying a

more humanistic approach additional insights can be gained (VanPool and VanPool

1999:33-34). Studies have become focused on the effects of colonialism on indigenous

societies (e.g Headland and Headland 1997), with some making the claim that the past is

unknowable, especially since it is reinterpreted within the inherently biased mind of the

researcher (Van Pool and VanPool 1999:36, Kuznar 1996:163). Although attempts at

bridging the gap between the humanist and the positivist schools are attempted (VanPool

and VanPool 1996, 2001), at present it seems that the researcher must choose one approach

over another, with perhaps a “shared conceptual core” (Moore 1997: 273) as elusive as

universal human laws.

Returning to the progression of functionalist and processual approaches, another

way of explaining diversity is through understanding human adaptations to environmental

constraints. From the detailed data gathering of Rappaport combined with the systemic

nature of Binfordian model building, Stewards’s cultural ecology and White’s explicit

evolutionary perspective has emerged a related array of current approaches that include

behavioral or evolutionary ecology, behavioral archeology, and perhaps selectionist

(evolutionary) archaeology. Evolutionary ecology is “the study of evolution and adaptive

design in ecological context” (Winterhalder and Smith 1992:3), while behavioral

archaeology examines material remains and how they relate to human behavior (Schiffer

1999:166), and selectionist archaeology more explicitly uses overt Darwinism to explain

cultural phenomena, as opposed to culture itself (O’Brien 1996:1), and has an emphasis as

well on artifacts, wherein they are extensions of the human phenotype and so subject to

evolutionary, or selective pressures (Broughton and O’Connell 1999:157). What at first

glance seems to be a splitting of theoretical hairs may be less an issue of researchers

positioning themselves on an intellectual landscape and might actually be (as some argue)

emergent paradigms (O’Brien and Holland 1995).

Behavioral archaeology thus seems to be an independent version of Binfordian

approaches to explaining the material record. Indeed, Binford recognizes the similarities

between Schiffer’s approach and his own views on middle range research (Binford

1981:25), although he disagrees with his methods, and feels that Schiffer cannot extract

behavior from the archaeological record (Binford (1981:28), even while Schiffer explicitly

states that his focus is atemporal, in the respect that he is looking at the interaction of

people and material culture irrespective of time and place (Schiffer 1999:166). The

behavioral archaeologist hopes that by focusing on such relationships more general theories

can be developed that may help explain certain portions of human behavior, and that in

doing so archaeology can become a science of its own, contributing to and accepting

contributions from other disciplines (Schiffer 1999:167,168).

Selectionist archaeology focuses on artifacts as well, but in an adaptive context.

Because the human populations themselves cannot be studied, the artifacts become not just

a proxy, but an actual extension of the human phenotype, through which evolution, defined

as changes in cultural traits, is expressed (Lyman and O’Brien 1998:616). As with the

behavioral archaeologists, the selectionists argue that only through applying their brand of

theory to archaeological problems will archaeology become a science in its own right

(Lyman and O’Brien 1998:630).

Behavioral ecology, the subset of evolutionary ecology that looks at behavioral

variability (Broughton and O’Connell 1999:153), especially within less complex societies,

relies heavily on optimal foraging models as an explanatory device for many levels of

diversity and social integration (Kelly 1995, Smith and Winterhalder 1981:11), presumably

working from the assumption of subsistence as central to survival of humans as a species

(Winterhalder and Smith 1981:x). The main proponent of behavioral archaeology has

explicitly removed himself from any connection with optimality, stating that general

theories of artifact design are more inclusive of behavioral and social variation (Schiffer

1999:167). A primary text on evolutionary archaeology has no indexed mention of

optimization or optimality (O’Brien 1996), based on the argument that evolution requires

only variation and inheritance (as seen in the phenotype as expressed through the artifacts);

optimization, as seen through fitness, is necessary only for evolution through natural

selection (Lyman and O’Brien 1998:616).

The conflict between these approaches is not easily resolved. Evolutionary

ecologists disagree with the scope of study of evolutionary and selectionist archaeologists,

arguing that phenotypic adaptation to various factors more clearly explains human variation

than the “direct action of natural selection and other Darwinian processes on heritable

variation in artifacts and behavior” (Boone and Smith 1998:S141). Evolutionary

archaeologists laud the contributions of evolutionary ecology and behavioral archaeology to

their domain (Lyman and O’Brien 1998:615), while the behavioral archaeologists offer new

insights (albeit perhaps somewhat belatedly) to a whole range of social issues (Schiffer

1999:167-168).

All these approaches are of interest to the archaeologist with an evolutionary bent.

Some argue that the differences are less than might be supposed when reading the primary

authors, and based, perhaps to some degree, more on the scale of observation than real

differences in approach (Lanata 1998:636). If archaeology of the evolutionary persuasion

is actually a sort of paleobiology, both micro and macro evolutionary processes should

work in tandem, each supporting the other (Lanata 1998:637, Denet 1998:S158).

Unfortunately, perhaps, those advocating the various approaches refuse to budge, and

indulge in polemical debates that serve mostly to further widen the gap (e.g. Smith 1998,

Lyman and O’Brien 1998:642).

The researcher, therefore, in order to establish some level of consistency, must

choose between various paradigms, regardless of whether they represent a mature science

or one in crisis (Kuhn 1996), as perhaps archaeology continues to be. Behavioral

archaeology is therefore removed from further consideration except for the usefulness of its

functional explanations, while evolutionary archaeology can be seen as an extension of

evolutionary ecology, especially in respect to evolutionary mechanisms such as fitness

(Simms 1987:9-13) although cautiously if using optimality models (Broughton and

O’Connell 1999:158-160). So although it is tempting to use the two in tandem, for present

purposes it is better to focus on one or the other, in this case behavioral (evolutionary)

ecology and its heuristic device, optimal foraging theory.

Behavioral ecology focuses on variation in such things as subsistence patterns,

family structures, fertility and morbidity as expressed in individuals within a broader

context of evolutionary theory, providing measures of reproductive fitness (Bailey 1991:3-

4). The emphasis on individuals is based on the fundamental aspects of natural selection;

there is inherited variance in phenotype among individuals that affects the ability to survive

and reproduce (Smith and Winterhalder 1992:26). A portion of the human phenotype is

cultural behavior, which from a “weak sociobiological” position is the tendency to select

from behaviors which in the long run increase reproductive success, and need not be

specifically programmed genetically, as there are innate human physical and mental

characteristics that serve the same purposes (Kelly 1995:51). The concept of fitness is

refined from simple reproductive success to one of reproductive potential, or the propensity

of an organism to reproduce within its given environment (Smith and Winterhalder

1992:27, reiterated in Kelly 1995:52). The two means by which this occurs in humans is

through methodological individualism, wherein humans store knowledge that they

understand to be useful towards linking actions to goals while maximizing opportunities to

reach those goals (Kelly 1995:53), and through optimization.

Optimization can be glossed as an assumption that actors choose from a set of

choices within certain constraints in which there is a currency that can be measured in terms

of relative success (Smith and Winterhalder 1992:50). When the actors are hunter-

gatherers, the choices can be described as subsistence strategies within local environments,

with the currency set as food value, or more basically, energy. Energy, then, serves as a

proxy for reproductive fitness, as fitness tends to vary directly with foraging success

(Winterhalder 1981:20). It is from these parameters that optimal foraging theory develops,

aspects of which include diet breadth and patch choice (Winterhalder 1981). Diet breadth

looks at the range of potential food items, and patch choice examines how resources are

distributed across the terrain. There are three predictions that can be applied to human

foragers: that foragers prefer profitable resources; they will be more selective if such

resources are readily available; and they will choose not to exploit readily available

resources if they are outside the optimal diet (Krebs and Davies 1978, in Simms 1987:14-

Critiques of optimal foraging include its apparent lack of recognition of different

value systems among various groups, especially in regards to prestige activities and those

linked to taboos and other culturally mandated mores (Kelly 1995:52, 109). Optimal

foraging theory would also have individuals eating their returns themselves, rather than

sharing the catch among non-family (Dwyer 1985:243-244). And what about simple taste

preferences? These complaints are answered by asserting that optimal foraging theory

produces models that are not realistic descriptions but analytical tools, and that they create a

framework within which to understand diversity; when items not fitting the model are

found other explanations can be attempted (Smith and Winterhalder 1992:60, Kelly

1995:109). For instance, when the larger construct of behavioral ecology is applied, the

arguments surrounding sharing can be easily dealt with by looking at fitness within a larger

context. More damaging are attacks on the underlying assumptions and methodologies.

One concern is that of the borrowing of methodologies from other disciplines, due

in large part to differences in approach and in the questions being asked, as well as the

underlying structure of the borrowed approach (Keene 1983:141-142, 147-148). If the

concept of borrowing is allowed, it might be asked whether the borrowed concepts

themselves are valid. Martin (1983) takes the underlying assumptions of optimal foraging

to task, arguing that maximization, diet breadth, and patch choice models are either

illogical, use incorrect measures, or just cannot be justified due to a departure from realism

(Martin 1983:627). This last is perhaps the most damaging, because at least from Martin’s

viewpoint, it can no longer be used as a basis for an idealized model (Martin 1983:621), as

indeed that is how it is frequently applied (Winterhalder 1981:19,20, Smith and

Winterhalder 1981:12, Smith and Winterhalder 1992:60, Kelly 1995:109, Foley 1985:222,

Simms 1987:20).

An approach that might help clarify this disjunction lies in understanding the

confusion between theory and method. As stated above the theory of optimization rests in

evolutionary (behavioral) ecology, and optimization is merely the middle range set of tools

used to predict behavior, from which additional questions can be formulated based on the

relative fit of the data (Simms 1987:19). By looking at the “context” of the behavior in

question such models will become more useful (Jochim 1983:158) and better able to

address such issues as cultural preferences (Simms 1987:20). By turning the focus away

from the divisive issues of appropriate methodologies and instead accepting that broader

conceptual frameworks are necessary to meaningfully address human behavioral variation

(Bettinger 1987:138) which becomes more clearly defined when the evidence does not fit

the model (Cronk 1991:31), appropriate data sets receiving appropriate levels of analysis

will continue to contribute to the advancement of the science.

The flow of energy through anthropological thought does not end with evolutionary

ecology or optimal foraging methods. Systems theory, cybernetics and the embedded

concepts of feedback have long been recognized as either maintaining stasis or initiating

change (Trigger 1989:303-304). Feedback can help maintain or promote fitness (Smith and

Winterhalder 1992:42-43). Just as energy flows through a social system, so does

information (Moore 1981:194) with society becoming a nexus of information processing

(Moore 1983:173), and information containing “material correlates” (Root 1983:194).

Information could thus become a proxy for energy, or, perhaps more realistically, energy a

proxy for information. Meanwhile, a non-linear concept of evolution, based, in part, on the

feedback of social processes, emphasizes a coevolutionary perspective, wherein humans

“are active participants in a…process with the natural world” where the “social informs the

natural and the natural informs the social” (McGlade 1995:116, 114).

Against this backdrop lies another biological paradigm, that of landscape ecology

(Neveh and Leberman 1984). This approach challenges many of the established views of

ecological studies, in particular concepts of climax and equilibrium (Naveh and Leberman

1984:10). Because energy and matter, according to the first law of thermodynamics, are

essentially equivalent, energy can become the focus for material systems, in which humans

are an inextricable part. The entire human system, which includes both the physical and the

mental, becomes subject to feedback, and, as part of the natural world, influences and is

influenced by the “natural” world (McGlade 1995:114).

Such an approach helps remove an emphasis from “sites,” especially in an

archaeological sense, and the artifact becomes the “minimal operational unit” (Thomas

1975:62), allowing a fuller integration of human behavior into the broader landscape (Ebert

1992:12-13). The lessened emphasis on specific loci of activities allows a greater focus on

larger scale questions of human integration into the environment, and also aid in questions

of site “significance” (Butler 1987).

Energy studies are an attractive method for studying human behavior. In its purest

form, energy is the ultimate determinant of culture; culture, and all it entails, cannot exist

without it. At the same time humans are imbued with the capacity to alter not only how

they acquire and utilize energy, but how they conceptualize such use. This has resulted in

various approaches of understanding energy consumption, as well as denials of its

relevance in human studies. To date, optimal foraging models couched within the

framework of evolutionary ecology hold great promise for elucidating behavioral questions.

Meanwhile, new concepts that revolve around aspects of feedback and information

exchange may well be harbingers of a new paradigmatic approach.

The present study examines the energetic returns of Rabdotus species snails from

the perspective of optimal foraging theory. The subject lends itself well to testing the diet

breadth model, wherein food items with low energy value enter the diet when higher ranked

resources drop in abundance. As diet breath widens, changes in patch choice or utilization

would be expected. The simplest means of measuring energy is through calories. Different

food sources can be easily compared using that currency. Calories, however, are not the

sole benefit of food consumption. The health of any higher organism requires the correct

amounts and ratios of appropriate compounds, vitamins, and minerals. By expanding the

currency to include these other basic needs expanded or alternative models explaining

foraging choices can be presented (Kelly 1995:101-108). The general approach is the

same, but the scale of analysis changes, allowing differing levels of interpretation. Of great

importance, of course, is understanding the focus of study, in this case, the central Texas

Rabdotus species snail.

CHAPTER 3

TEXAS SNAILS

Sources

There is no single source that summarizes all snail species within Texas, or within a

single region within Texas. In the 1940s Henry Pilsbry compiled four volumes of data on

North American land snails (Pilsbry 1940, 1946, 1948), but the volumes are difficult to

access and contain much outdated taxonomy, and are therefore most useful for the

illustrations (Ken Brown 2000: personal communication). Between 1971 and 1973 E. P.

Cheatum and R. W. Fullington produced a series of bulletins for the Dallas Museum of

Natural History describing the aquatic and land mollusca of Texas (Cheatum and Fullington

1971a, 1971b, 1973). Cheatum died before the project was completed (Fullington and Pratt

1974:ii) and Fullington , assisted by W. L. Pratt, produced one more volume in 1974

(Fullington and Pratt 1974). The series was never finished, and although very useful at

times, it contains omissions that can prove frustrating. Further, it describes no aquatic

species, other than in the supplemental key (Cheatum and Fullington 1971b). Perhaps a

precursor to the Dallas Museum bulletins, D. C. Allen and E. P Cheatum published a short

but very informative summary of land and aquatic snails in the 1960 Bulletin of the Texas

Archeological Society (Allen and Cheatum 1960). Of interest was an emphasis on snails

found within archaeological sites.

The major references require supplementation from scattered reports from various

sources, and even these often lack information that might be of interest or relevance, both

from a natural history and an archaeological perspective. Very little is known about the

most basic aspects of snail ecology; reproduction, life spans, environmental preferences,

etc. In fact, it is not known what the most commonly recognized snail species in

archaeological assemblages, Rabdotus, eats (Brown 1999:251, although see Randolph

1973, for strong evidence of plant consumption).

Species, Morphology, and Distributions

By combining information from the Dallas bulletins and Allen and Cheatum’s 1960

BTAS publication it is possible to begin to inventory Texas snail species. Aquatic snails

are represented by at least 10 families containing 18 species (Cheatum and Fullington

1971b). Six of these families and 11 associated species are commonly found in

archaeological contexts (Allen and Cheatum 1960). Land snails exhibit a much richer

diversity. Twenty-one familes with 35 genera containing over 140 species are documented

(Cheatum and Fullington 1971a, 1973, Fullington and Pratt 1974). Of these, 14 families

containing 32 species are reported to be common in archaeological sites (Allen and

Cheatum 1960). Another source (Hubricht 1985) indicates 127 land snail species are found

in Texas. This discrepancy in numbers is probably largely due to exclusion of non-native

species and those found west of the Pecos River.

The range in species is reflected in range of phenotype. Fourteen major shell forms

are described as globose, depressed, discoidal, domed, bulimoid, pupilliform, conical, and

turbinate, among others. Other diagnostic features of shells include number and direction

of body whorls, presence or absence of a lip at the shell aperture, or opening, presence or

absence of lamella, also called teeth, also at the shell opening, and an open or closed

termination of the whorls on the underside of the shell, described as either perforate or

imperforate. Shell size ranges from around 30-35 mm to less than 1-2 mm. The animal

which inhabits the shell, the gastropod, presents a whole new range of morphologies (see

Purchon 1977, for details of anatomy).

Snails are found across the state. Distributional maps in Hubricht (1985), and

Cheatum and Fullington (1971, 1973) and Fullington and Pratt (1974) show that some

species are widespread, indicating a broad range of environmental tolerance, while others

are seen to cluster in various regions of the state, denoting narrower environmental

preferences. Still others are represented in only a very few counties.

The environmental preferences suggested by regional distributions are also seen on

a more local scale. These descriptions, however, are widely variable, depending, no doubt,

on available literature and observations of the various authors. The species Holospira

goldfussi, for instance, is distributed largely across Central Texas, but its more specific

habitat is described merely as “associated with limestone rock and humus” Cheatum and

Fullington (1973:37-38). Descriptions for other species’ habitat preferences are more

useful, illustrating such variables as moisture preferences and zonation in grass or

woodlands.

Other information is also inconsistent. Some comments help clarify distributions

and morphology, while others indicate that very little is known about a particular species.

More species specific data requires searching through literature sources from the natural

sciences or specialized journals (e.g. Hubricht 1982, Randolph 1973). In general, the

quality and quantity of available knowledge is highly variable.

Archaeological Snail Studies

Sites. Archaeological investigators have been including snails within their reports

for many years, but there has been little constancy in level of detail or analysis. Some

reports mention snails largely in passing, under sections such as “Non-Vertebrate Faunal

Remains,” although others attempt, with various degrees of success, to incorporate snails in

some aspect of site interpretation. A sample of some of the more involved studies are

summarized briefly below.

Raymond Neck’s (1994) analysis of non-vertebrate remains at Mustang Branch in

Hays County was a succinct summary of species collected and implications of species

diversity, with an emphasis on Rabdotus. Change in species ratios at this site were

inconclusive in reconstructing paleoenvironments. The discussion of holes found in

Rabdotus shells, (from roots and screen damage), and habits of the snail were especially

useful.

Henry (1995) compares seven sites in the Hog Creek basin of North Central Texas

and compared their frequencies with those of pollen and vertebrate fauna to argue for an

increasing woodland replacing grasslands. Species of Oligyra and Rabdotus varied

inversely, with the woodland adapted Oligyra replacing Rabdotus over time.

An exception to the general disregard of snails by some authors is LeRoy Johnson,

who makes an effort to explain, or at least describe, the presence of snails in sites he has

reported on. In 1962 he stated that snails and shellfish were likely gathered by women as a

regular part of the subsistence regime (Johnson et al. 1962:47). In a series of reports

produced for the Texas Department of Transportation (e.g. 1991, 1995, 1997) snails and

molluscan remains received generous attention as a means of environmental reconstruction

(1991), patterns of site use (1995), and general descriptive data (Neck 1997). More

recently, he argued that quantities of Rabdotus snail found at the Bessie Kruze Site in

Wiliamson County were the result of overbank flooding bringing in drift deposits (Johnson

2000).

Ken Brown (1999) has recently produced what is probably the definitive work on

snails in regard to methods of environmental reconstruction and subsistence questions.

Based on data from the Smith Creek Bridge Site in DeWitt County, he presents an analysis

that summarizes the current state of knowledge of snail use in paleoenvironmental studies

and subsistence models. This report will be a valuable asset to anyone interested in these

aspects of snail studies.

Ellis et al. (1996) and Lintz and Abbot (1997), meanwhile, have been active in using

snails to obtain dates for archaeological deposits using amino acid racemization and carbon

dating techniques. These methods are proving useful for absolute dating of archaeological

remains, and for helping to determine integrity of buried deposits.

Many other examples could be cited. What becomes clear though, in this very brief

literature review, is that the use of snails to understand archaeological sites in Texas has

been building for a number of years. Early studies recognized the potential for snail

analysis, and later works have been developing a framework from which future studies can

proceed. The following section examines three areas of snail studies: use of snails for

dating of archaeological deposits, for reconstructing past environments, and for

understanding prehistoric subsistence patterns.

Method: Dating. The dating of snails has been refined to the point where there is a

real possibility of gathering valuable information from snail shells in archaeological

contexts. It was recognized quite early that snail shells might be useful for providing dates

for archaeological assemblages (Allen and Cheatum 1960). Snails precipitate carbonates

that are ingested from local limestone or soils, and the shell therefore dates much older than

the snail itself (Goodfriend 1992:665). It is necessary to test a modern, preferably pre-

atomic bomb sample to enable use of a corrective factor to adjust for an up to 3000 year

discrepancy in carbon dates (Ellis et al. 1996:192). This age anomaly can be corrected for

on a regional basis (Lintz and Abbot 1997:15), and by extension, a database could

conceivably be initiated that would allow for local correlations.

Amino acid racemization and epimerization is perhaps more directly applicable to

snail studies. The difference between the two methods is not immediately clear, and may

be minor, as both are based on the fact that an L-form of a particular amino acid converts

(racemizes [Ellis et al. 1996:192] or epimerizes [Ellis and Goodfriend 1994:184-185]) to a

D-form upon death of an organism. Johnson states that the difference is that in

racemization a true mirror image is produced, unlike the results of epimerization (Johnson

2000:61). Regardless, once the rate is determined it can be calibrated with other absolute

dating methods resulting in a quick, cost-efficient dating method (Ellis and Goodfriend

1994:185).

These methods may be utilized for directly dating archaeological deposits. They

can also be used for determining site integrity. Snails and other carbon-bearing materials

can be extracted from excavation levels and used to determine potential for mixed deposits.

If the dates are not comparable, the site is likely mixed; if the sample indicates clustering of

ages, the deposits are likely intact. At 41ZP39 and 41ZP176 snail and charcoal samples

were dated by AMS methods, and by statistical comparison it was determined that the site

maintained enough vertical integrity to warrant further testing (Lintz and Abbot 1997).

Racemization rates of snails were used by Ellis et al. (1996) indicating that a number of

sites at Fort Hood contained mixed deposits.

Method: Paleoenvironments. Reconstruction of paleoenvironments is another

direction snail research has followed. Snails are capable of informing about past

environments in much the same way as other fauna, and it is the smaller, “microscopic”

snails that are more subject to selective pressure, and so are more reliable indicators of

surrounding environmental variables (Brown 1999:213). There are two methods of gaining

information on past environments from snails. One is through survey level data using local

and regional collections, and the other is through experimental studies (Goodfriend

1992:666). Survey data has been used for determining such variables as biome abundance

or frequency, elevation, rainfall amounts and frequency, temperature, and moisture

(Goodfriend 1992: Tables 1 and 3). An assumption that environmental requirements do not

change is necessary to support a good fit with known ecological parameters of modern

populations (Allen and Cheatum 1960:292). This assumption of evolutionary stasis is

expressed through relative scarcity or abundance of snail species based on fluctuations in

favorable climates, ignoring the implications of selection embedded in this comparative

process (Goodfriend 1992:669).

An equally complex issue is determining relationships between different aspects of

the environment. Variables that interact to produce today’s climatic regimes may not have

been in place in the early Holocene, when the factors controlling the Earth’s orbit were

different enough to produce increased seasonality in the northern hemisphere relative to

present conditions (Goodfriend 1992:669). Careful measurement of snails from datable

contexts may help resolve some of these issues, as shell size is dependent partially on

available moisture and temperature, as well as population density (Brown 1999:217).

Comparative studies utilizing other lines of evidence may allow environmental factors to be

teased apart from micro-evolutionary changes.

Another means of reconstructing past climates is through experimental research on

present populations (Goodfriend 1992:666). Controlling primary factors of light,

temperature and moisture can provide information on mortality rates, reproduction, feeding

habits, and mobility (Goodfriend 1992:667). Randolph (1972) conducted experiments on

two species native to central Texas, Mesodon roemeri and Bulimulus dealbatus (Rabdotus).

She was able to show that a fluctuating environment results in generalized species behavior,

and conversely, less species diversity (Randolph 1972:934). Using a standard biological

diversity index (Shannon-Weaver), it became apparent that a less variable environment

(woods), contained a richer diversity of snail species than did the more diverse grasslands,

where snail variability dropped (Randolph 1972:936-937). The seeming discrepancy of

grasslands described as environmentally more diverse than woods is due to a greater range

in temperature and relative humidity in the grasslands (Randolph 1972:936) and may also

be the result of a number of micro-habitats (downed wood, small bushes, etc.) within the

broader grass zone (Ken Brown 2000: personal communication).

Method: Subsistence. A long-standing issue revolves around the question of

whether snails formed a portion of the subsistence base or whether their presence in

archaeological sites is the result of enriched human midden deposits attracting existing

populations. Although it is generally accepted that Rabdotus species were a food source for

prehistoric populations (e.g. Simmons 1956, Allen and Cheatum 1960, Jelks 1960, Johnson

1964), some others maintain that even the extremely dense populations seen at some

archaeological sites are the result of “commensal scavengers” (Brown 1999:243). A

method that may help resolve this issue, the use of off-site control samples, is little utilized

(Brown 1999:244). If on-site snail deposits are denser than those found off-site, there will

be strong evidence for a correlation between human and snail populations, although what

kind of relationship will still require clarification.

Brown (1999) argues that an active campsite is a very poor environment for active

Rabdotus populations; foot traffic and soil compaction resulting in lessened soil moisture

would not support viable populations. Not until the site has been abandoned for a long

enough period to revegetate will it be favorable for recolonization. Therefore, in a well

stratified site, snails should be found in zones free of cultural material, if they are indeed

recolonizing previous human occupation zones. It remains possible that enriched soils

would support rich plant growth that potentially might reach a level supporting snails more

rapidly than surrounding areas. This factor, combined with mixing of deposits could

account for the dense concentrations of snails seen in many sites (Brown 1999:243-248). A

possible objection to this line of thought (if subsistence is being argued for), that other snail

species should follow similar patterns, can be countered if there is a lack of snail

concentrations by species other than Rabdotus (Brown 1999:249).

Ethnographic accounts indicate that snails were used as a food resource. Apparently

Cabeza de Vaca witnessed consumption of snails by Native Americans (Clark 1969:43,

1976, Hester and Hill 1975). North African groups, both recently and prehistorically,

conduct activities that result in large piles of burned rock, called rammadyat, that are quite

similar to the burned rock middens of central Texas (Honea 1962:317), and one of the

primary purposes seems to be the preparation of snails and other food resources (Honea

1962:318). The modern Hadza of Tanzania are reported to harvest a particular species of

land snail during the wet season (Woodburn 1970:45). The modern Maya collect snails for

subsistence purposes and evidence strongly suggests prehistoric populations did as well

(Healy et al. 1990).

Archaeologically, snail clusters accompanied by cultural material is good evidence

for snail consumption, and Brown lists a number such cases, some where snails numbered

in the thousands (Brown 1999:248-249). Looking at ratios of adults to juveniles may also

be of use. If adults are present in numbers exceeding those found in general populations it

is reasonable to suggest that they were being selectively gathered (Neck 1994:496). Clark

calls for an analysis of coprolites (Clark 1973) and although snail shell fragments have been

found in some samples, diagnostic body portions such as radulae, part of the feeding

mechanism (Clark 1969) have not been recovered (Clark 1973, Brown 1999:250), which

indicates that the recovered shell may have been introduced accidentally into the diet.

Although it appears that snails (Rabdotus sp.) could have been, and probably were

consumed on a fairly regular basis, another line of thought is to ask if they should have

been eaten; i.e., following on optimal foraging theory can it be shown that snail

consumption would be a rational and energetically realistic subsistence choice within a

prehistoric diet.

Potential Of Optimal Foraging Theory To Understand Snail Consumption. As

introduced above, optimal foraging theory includes the concepts of diet breadth and patch

choice (Kelly 1995:97). Diet breadth predicts whether a resource will be taken during a

foraging excursion and is based on total acquisition costs (search and handling) compared

to return rates (Kelly 1995:79). The result is ranked resources from which choices of

acquisition can be made. Higher ranked resources will be utilized as primary food sources

and diet-breadth will be low. As the availability of higher ranked resources decreases

acquisition costs rise, and to maintain efficiency in return rates lower ranked resources

become incorporated, and diet-breadth increases (Kelly 1995:84).

Incorporating resource “patches” into the model more accurately depicts

distributions of resources across any particular section of terrain. Searching a resource

patch becomes part of acquisition costs, and a patch remains productive as long as it can

provide a return rate higher the mean of the total environment, once the costs of moving to

that patch are factored in (Kelly 1995:91).

Combining these two models allows prediction of which area will be chosen and

what will be the focus of the acquisition activity (Kelly 1995:97). Optimal foraging theory

thus becomes a method from which predictive or explanatory models from a wide range of

situations can be tested (Smith and Winterhalder 1992:51). Optimization can also be placed

within the broader perspective of evolutionary ecology, which examines how potential

reproductive fitness determines human choice-making, and, ideally, why some choices are

made over others (Smith and Winterhalder 1992:60)

Differing return rates are dependent on several factors. For instance, in the Ache

diet, the paca has a higher number of kilocalories per unit than does deer, but also has a

much longer handling time (encounter plus acquisition), and so has a substantially lower

return rate, and correspondingly is ranked lower than deer (Kelly 1995: Table 3-5, 85). If

only acquisition and processing costs are calculated food sources can be ranked in a more

general sense (Kelly 1995:79-80, Table 3-3). It follows that if processing costs are

unavailable, then indices of nutrition, such as calories, protein, fats or carbohydrates must

be used as a baseline to which experimental or ethnographic data can be added.

A standard application of optimal foraging models involves the use of net calories

for any particular food item (Simms 1987, Kaplan and Hill 1992:169, Bettinger 1987:133,

Hawkes and O’Connell 1985). Experimental gathering exercises coupled with empirically

obtained caloric values result in tabular arrays of resources in rank order. The energy-as-

currency debate has led to the questioning of the relevance of optimal foraging approaches

(Martin 1983, Bettinger 1987:134) and perhaps more usefully, to a reevaluation of the

currency. Although energy may be the simplest approach (Kelly 1995:102), there seem to

be an increasing use of more involved models which recognize the importance of various

aspects of diet. Keene for example, looks at the Netsilik Eskimo and determines that if only

caribou utilized to meet their base energy requirements there would be resultant, major

deficiencies in calcium and ascorbic acid (1979:390). Ache men seem to concentrate their

expenditures acquiring meat which has a lower return than other gathering acquisition

activities they could chose (Hill 1988). One possible explanation is that by continuing to

hunt, the mean foraging return rate is lowered, thus ensuring, according to optimal foraging

theory, wider diet breadth with a greater range of nutrients. The problem, of course, is that

the initial premise runs counter to optimal foraging predictions; if the men can raise their

caloric return, they should do so, even should it mean that they forgo hunting activities in

lieu of gathering. This assumption in turn denies the potential for increased reproductive

fitness the prestigious act of hunting confers on successful men (Hawkes et al. 1991:89).

An increase in variables requires an increase in model complexity. This has been

attempted through linear programming (Belovsky 1988, Keene 1979, Reidhead 1980), and

indifference curves (Hill 1988, Kaplan and Hill 1992). These models are complex and

difficult to approach, and in part, perhaps, for these reasons others have used somewhat less

rigorous inductive techniques based on a general but increasingly refined knowledge of

basic nutritional requirements (Speth 1991, Sobolik 1991, O’Dea 1991) with relative

resource abundance (Sih and Morgan 1985), mechanisms of food sharing (Hawkes et al.

1991) and time management (Smith 1979:70) all being recognized as confounding factors

in “early” (Hill 1988) or “simple” (Sih and Morgan 1985) optimal foraging models.

The nutritional value of Rabdotus species has not previously been known, but it has

been thought to be high in protein and low in carbohydrates and fats (Brown 1999:250).

Brown presents figures of generic cultured snails as containing approximately 80 kcal, 16

grams of protein, 2 grams of carbohydrates, and 1 gram of fat per 100 grams of snails. This

compares well with snails known ethnographically to be consumed by lowland Maya

populations (Healy et al. 1990), although the carbohydrate values of the aquatic snail they

consume is considerably higher, at 12 grams per 100 grams of meat. Kilocalories are

comparable to rabbit (73 kcal/100gm) but considerably less than deer (126 kcal/100gm),

and both mammals contain higher amounts of protein and fats, but no carbohydrates (Healy

et al. 1990:Table 2, 178). The post encounter return rate for deer in the Great Basin

averages to 24,700 kcal/hour, while that of jackrabbit averages to 14,400 kcal/hour (Kelly

1995:Table 3-3). Based simply on return rates deer would be ranked higher than rabbit.

Because return rates for snails are not known it is possible to use a simple comparison

based on total kilocalories. Such an approach would run counter to optimal foraging theory

through the abandonment of energy balance (return rate) principles, and furthermore, as

will be shown below, would result in drastically erroneous conclusions. Snails would be

ranked higher than rabbit, but lower than deer.

Diet breadth has now been addressed, but the question of patch choice remains to be

clarified. Rabdotus is colonial in its habits, maintaining localized populations that become

active during periods of high humidity (Fullington and Pratt 1974:14). The species escapes

high temperatures by climbing above super-heated ground and estivating on upright

vegetation (Randolph 1972:934) or seeking shelter underground (Hubricht 1960:69) or

under rocks and logs (Fullington and Pratt 1974:14). Colonies may be as large as a city

block (Hubricht 1960:69). Densities of 1.8 to 18 individuals per square m could therefore

be found in prickly pear (tuna) patches along with rabbits and woodrats (Brown 1999:250),

and presumably in other locations as well.

Rabdotus, then, is a prime candidate for testing with an optimal foraging model. Its

colonial, or “patchy” nature combined with periods of high availability, and thus low

acquisition costs, might tend to boost its ranking relative to otherwise more valuable but

potentially less predictable resources having higher associated costs. Under the right

conditions, a dense patch of snails could conceivably become highly ranked within a diet

breadth widened by even a relatively minor fluctuation in larger game animals. Once

Rabdotus species are quantified as to nutritional value, and experimental gathering and

processing activities are conducted, a clearer picture of when Rabdotus might enter a

particular subsistence strategy should emerge.

CHAPTER 4

DEFINING THE STUDY AREA

Site 41BL116 in the Central Texas Lampasas Cut Plain provides the archaeological

data used to support the contentions presented herein. The site is representative of

occupation sequences consistent with the Late Archaic and Late Prehistoric periods in

Central Texas. This chapter begins by briefly introducing the site and then placing it more

fully within the known cultural chronology for the region. Central Texas is not only a

cultural area, but an environmental zone as well. Various implications of environment are

therefore discussed as they relate to the physical and cultural aspects of the study area.

The Site

Site 41BL116 is a stratified open camp located on an alluvial terrace some 40 feet

(12 m) above the junction of the Lampasas River and a tributary creek in southern Bell

County, Texas (Figure 1). Test excavations coupled with examination of looter-pit profiles

indicate main occupation during Late Archaic times and a distinct but seemingly more

ephemeral occupation during the Late Prehistoric period. Temporal diagnostics are

Pedernales dart points at one extreme, and a Perdiz arrow point and broken ceramics at the

other. In between are Williams, Marcos, Montell, Ensor, Fairland, Darl, and Scallorn

points. Burned rock is dense in Archaic levels and bone, mussel, and snail is well

preserved. Total depth of deposits is approximately 1.5-2 m.

Besides the diagnostic projectile points, a large number of bifaces in various stages

of completion have been recovered, as well as waste lithic material associated with such

activities. The lithic assemblage has not yet received intensive analysis, but preliminary

assessments indicate most flakes are small (1-3 cm) and generally lack significant amounts

of cortex. Cores and large chunks are virtually nonexistent. When flakes larger than 3 cm

in any one dimension are examined, a large proportion of them show evidence of use.

Numerous informal tools are present, most often represented by flakes which show

evidence of use or intentional retouch. Formal scrapers, however, are rare, as are gouges

and adzes.

To date, 259 tools have been recognized, of which 100, or 39%, are considered

informally or expediently used flakes. Out the remaining 159 formal tools, 66, or 41.5%

are recognizable projectile points, while 85, or 54.5% are unfinished bifaces. As single

gouge and seven formalized unifaces (scrapers) round out the formal tools.

Groundstone is also present, most notably in the presence of a large, bifacial, basin

shaped metate. Handstones, or manos, have been recognized, but most often were located

out of context. The overwhelming majority of raw lithic material, other than chert, is

limestone, which makes recognition of grinding implements problematic.

Site Area

Figure 1. Location of site 41BL116 in Central Texas.

A number of burned rock features have been documented. These typically are

shallow basin hearths, usually around 60 cm in diameter, and containing one to three

courses of stone. Other, smaller clusters of burned rock are also present, and may be rake-

out piles or small hearths. In other instances burned rock is densely packed within levels,

but with no recognizable patterning, and perhaps may best be described as sheet or proto

middens. In one instance, what appeared to be a rock-filled pit was recognized in the south

wall of the block area. It was approximately 40 cm in depth and narrowed from

approximately 60 cm in diameter at the top to perhaps 20 cm in diameter at its base.

Unauthorized excavators unfortunately destroyed much of this feature within the wall, but

not before it was mapped and photographed. This feature is immediately adjacent to what

may be the largest hearth-like feature recognized to date, a basin that may be 1.5 m in

diameter and up to 30 cm thick.

The most common item found within these deposits are snails, in particular

Rabdotus and Olygira species. Mussel shell is also extremely common, and often found

burned and in direct association with burned rock features. Features consisting of

concentrations of snail, mussel, lithics and bone are not uncommon. A number of these

have been collected in their entirety. One such feature contained two unmatched mussel

shells placed lip to lip, with the resulting cavity containing a Rabdotus snail shell and a

fragment of bone.

A single 1 x 1 m unit has been the focus of detailed data recovery, with an emphasis

on snails. Both 1/4 and 1/8 in screen have been used for all matrix, and substantial flotation

samples have also been collected. The result is an added level of control in snail recovery,

and it is the data from this unit, referred to here as the test column, that is the basis for the

analyses presented in this project.

Bone at the site seems to be well preserved, although generally fragmentary, usually

appearing splintered and broken. No large, complete pieces have been recovered, but a

cursory examination indicates most can be classified as small to medium mammal, and

some deer has been positively identified (Barbara Meissner 2000: Personal

Communication). Complete bone have typically been phalanxes, most probably from deer,

and occasional rodent and perhaps bird bones recovered from 1/8 in screens. A few fish

vertebra have also been recovered, although no otoliths have been recognized.

Soil samples have been retained from the test column, as well as from feature matrix

and levels in which there is a perceived quantity of charcoal. General matrix samples have

been floated, and have produced quantities of “microscopic” snails accompanied by various

amounts of organic material (primarily charred wood). Three feature flotation samples

were submitted for macro floral analysis, but the amount of charred material in the matrix

was insufficient for detailed analysis (Phil Dering 2001: Personal Communication). Soil

samples were also submitted for analysis of pollen and diatoms. The pollen analysis

provided data indicating that plant species presently in the area were present prehistorically

as well, and there was evidence of differential preservation, limiting somewhat the utility of

the analysis (John Jones 2001: Personal Communication). A diatom analysis was

somewhat more fruitful, and indicated that water conditions prehistorically were, at least at

times, substantially different (generally more marshy or lacustrine) then at present (Barbara

Winsborough 2000: personal communication).

Four carbon samples were submitted for dating, three by liquid scintillation

methods, and one by AMS methodology. The dates have been consistent with expectations,

(except for one that was dated to 285 ±40 years BP), falling at 3140 ± 45, 2385 ± 105, and

2065 ± 45 years BP, with older dates representing deeper stratigraphic levels.

These excavations are designed as test level investigations. They have indicated

that preservation is fair to good, disturbance is relatively minimal, and potential for data

recovery is high. Additional investigation, both at the site and in the laboratory, promise to

clarify many aspects of site function. Present levels of investigations have been sufficient

to initiate the present project, and to allow the interpretations presented below to be derived.

Site data is presented as needed below in more detail to illustrate or support the

applications or interpretations. A detailed site description and analysis awaits completion

of field investigations.

The Study Area

Through examining various local ecological parameters a model based on broad

global patterns can be developed. This model can be used to test site data and to explore

regional patterns of settlement. The process begins by gathering empirical information on

various environmental aspects of the area of interest. These are compared to previously

assembled databases containing similar information correlated with ethnographically

known societies. A link between environment and culture is thus established, allowing the

qualitative aspect of culture to be placed within a quantitative frame of the natural world.

This is, of course, only an exercise, and not designed to be an end in itself, but rather a

means of establishing questions that can be asked of the archaeological record.

Central Texas Defined. The study area falls within the region normatively defined

as “Central Texas.” The term has various meanings. Central Texas is actually a construct

based somewhat on an aesthetic rendering of Texas into pieces, in part on observed overlap

in cultural markers, and in part on environmental commonalities. There can be seen

indicators that certain groups of people used the region for similar purposes at similar

times. As Ellis et al. (1995) point out however, the associated markers of these potential

groups, be they socially or technologically distinct, extend well outside of what is generally

referred to as Central Texas.

Ellis et al. (1995:Figure 1) summarize three of the more distinctive constructs of

Suhm, Brown et al., and Prewitt. Their regions overlap to various degrees, and regional

edges vary widely. The broadest area was defined by Suhm (1960) and encompasses large

portions of the Blackland Prairies and the Southern High Plains, as well as encroaching

upon the Pecos area and East Texas Piney Woods. Brown et al.’s (1982) region limits

northern and eastern boundaries, but extends the western portion deep into the Pecos

region. Prewitt (1981), strikes a middle ground, with boundaries more confined in a

visually central core.

Common to all these schemes is a multiplicity of Blair’s (1950) biotic regimes. All

encompass at least four of his biotic provinces, with Brown et al.’s very nearly approaching

a fifth. Central Texas, therefore, regardless of how it is defined, has available the resources

and characteristics of various ecological regimes, with a resulting ecotonal condition. As

Johnson (1995) states, far from being a distinct “province,” Central Texas is a transition

zone between more identifiable ecological areas. Ellis et al. (1995) extend upon this notion

and show some ten or eleven distinct biotic subregions, which are in turns islands,

surrounds, or intricate interfingerings of ecological zones. The result is a complex interplay

of factors that if taken to an extreme, could render the Central Texas concept irrelevant,

especially if the concept of culture following ecology is accepted.

Central Texas is therefore arbitrarily defined. Prewitt’s 1981 version of Central

Texas, which encompasses all of the Edwards Plateau, and adjacent portions of the

Blackland Prairies, Lampasas Cut Plains, South Texas Brush Country, and the Lower Pecos

(Prewitt 1981, 1985) can perhaps best be seen as a compromise solution, and one that has

established itself in much of the literature. When Central Texas is referred to in this study,

it will be a general reference to Prewitt’s boundaries. Of interest, though, is Ellis et al.’s

(1995) mapping of the overlap of some of the more common diagnostic artifacts generally

associated with Central Texas. This results in a much more restricted zone, and although

they do not make a specific argument for it, might be a reasonable alternative, one that also

includes the present study area.

The culture area is defined by similarities in observed and perceived cultural traits,

and further tied together by environment. If culture is shaped by environment, it might be

logical to first discuss the ecological parameters of a study area. Central Texas, however,

has a well-established cultural chronology which developed independent of complex

environmental considerations, relying more on recognition of cultural traits and seriation of

artifacts for establishing conceptual culture change. What follows, then, begins with a

discussion of the established culture history and concludes with the regional environment.

Culture History. The Central Texas Archaic is a period of Texas prehistory that is

linked by similarities in subsistence, technologies, social patterning, and most obviously,

projectile point styles. Before examining the Archaic specifically it is useful and perhaps

necessary to examine the underpinnings of first the period concept and then the

environmental bases that to a large degree helped shape the patterns visible in the

archaeological record.

The concept of “period” grew out of attempts by archaeologists to place the material

record into meaningful contexts. Drawing on McKern’s Midwestern Taxonomic System

(McKern 1939), early Texas practitioners, such as J. E. Pearce (1932), J. Charles Kelley

(e.g. 1947) and Suhm et al. (1954), began organizing the largely lithic artifact assemblage

based on stylistic attributes. As some of these were from obvious contexts, associations

were made between known time frames and stylistic commonalities, with a resulting

division of the prehistoric period into Paleoindian, Archaic, and Late Prehistoric or Neo-

American periods. The Archaic and Late Prehistoric periods were drawn in large part from

better studied and more well known Eastern Woodland assemblages, with the Archaic

representing pre-agriculturists pursuing a hunting and gathering economy, and the Late

Prehistoric representing introduction of horticulture and agriculture, ceramics, advanced

weaponry (the bow and arrow) and concomitant social complexity. Paleoindian peoples

were of course seen as nomadic hunters of extinct megafauna.

Although archaeologists of the 1930s and 40s initiated sequences of projectile

points in a chronological framework it was not until work by a new vanguard of

investigators in the early 1960s that the long-lasting cultural chronology only now being

substantially altered was introduced and partially substantiated. Of importance for the

Archaic period was work at Canyon Reservoir; the Wunderlich, Footbridge, and Oblate

sites (Johnson et al. 1962), work at Devil’s Mouth in the Lower Pecos (Johnson 1964), and

work at the Bell County Youngsport (Shafer 1963) and Stillhouse Hollow sites (Sorrow et

al. 1967). These stratified sites from three distinct portions of Central Texas built upon and

reinforced one another, and to a large extent defined the culture history of the Archaic for

the region.

Prewitt (1981, 1985), and before him Weir (1976) made attempts at further dividing

prehistory, particularly the long-lived Archaic, into phases. This was an attempt to refine

the culture history and make it more manageable and diagnostic, perhaps in hopes of

allowing more thoughtful inquiry into underlying causes of change. Unfortunately, it

resulted to some degree in a cookbook approach wherein a single diagnostic artifact might

result in assigning a whole suite of characteristics to any particular aspect of an

investigation. Although Prewitt himself cautioned that these were provisional and subject

to refinement, it was not until sometime after Johnson’s (1986) review of the problem that

these phases began to fall out of common use.

What was left then, was a return to Early, Middle and Late Archaic periods, which

were defined, and are being redefined, on a broader suite of cultural and environmental

factors. There is now an enhanced culture history in place (Johnson and Goode 1994, ,

Johnson 1995, Collins 1995), which provides the general framework of what happened and

when, against which questions of how change occurred can be placed. Underlying

questions of why this change happened can now be addressed more fully and meaningfully.

First evidence of human occupations in Central Texas date to what is known as the

Paleoindian period. This period is defined as prior to 8500 years BP. The Paleoindian

period has been divided into two distinct periods (Collins 1995: 376, Table 2), with the

earlier Clovis, Folsom, and Plainview cultures present at 11,500 B.P. These early people

are typically thought to have subsisted on varieties of big game, the Clovis on mammoth

and extinct forms of bison, the Folsom and Plainview on bison. New evidence is

suggesting that this view is in error, and that these people utilized the big game when

necessary or advantageous, but subsisted on a substantial percentage of smaller game as

well (Collins 1995:381). This early Paleoindian period was followed by a Late Paleoindian

period, which has subsumed portions of Prewitt’s Early Archaic. For example, the

Golondrina style point, placed in the Early Archaic by Prewitt, has been placed in the late

Paleoindian period by Collins (1995:376) based on distinctive features such as edge

grinding and size. Lifeways, however, seem to indicate a more archaic lifestyle (Collins

1995:382). This has been termed a transitional period, with Paleoindian strategies slowly

giving way to broader-based pursuits of the relatively more sedentary hunter-gatherers of

the Archaic (Johnson 1989:52).

The entire Central Texas Archaic spans some 7500 years, from ca. 8500 BP to

around 1250 BP. It can be characterized generally as a time of increasing human

populations adapting within a fluctuating but generally warming climate. Following

Collins (1995) the Early Archaic begins around 8500 BP, and lasts until 6000 BP. The

Middle Archaic follows and lasts until around 4000 BP, followed by the Late Archaic I to

2500 BP, and the Late Archaic II, to about 1200 BP. The Late Prehistoric, or as Johnson

now refers to it, the Post Archaic, follows, and here the phases mentioned earlier seem to

hold fairly well, with Austin phase peoples around until about 800 BP when a seemingly

true cultural horizon (Johnson 1994), the Toyah phase, began.

Foraging cultures are immediately dependent upon natural resources for subsistence.

It follows that much information about lifeways can be gathered if ecological conditions

can be ascertained. Collins et al.(1993) and Johnson (1995) have both examined lines of

evidence to suggest warming and cooling trends, and these are both through the proxy of

moisture, as temperature is very difficult to arrive at. Collins et al. depend heavily on

pollen analysis, which provides information on plant regimes from which climatic data can

be extrapolated. Johnson utilizes various lines of data, including pollen and microfauna

from buried contexts at Halls Cave, and also dated evidence of aggradation or lack thereof

of stream side terraces, with the assumption being that surfaces aggrade (or deflate) during

wetter times, but remain stable during drier times. Their interpretations agree very closely

for the Middle and Late Archaic, but are in direct opposition during much of the Early

Archaic. Collins is also somewhat more conservative, avoiding some of the fine-grained

peaks and valleys seen in Johnson’s reconstruction (Collins 1995:Table 2, Johnson

1995:Figure 35).

The Early Archaic was a time when persons were having to adapt to the widespread

extinction of the large animals that had existed during the preceding Paleoindian period.

Although the big game hunting nomadic lifeway has been shown to be largely a stereotype,

mobility was probably high and populations relatively low (Collins 1995:381, Johnson

1989). This basic way of life extended into the first part of the Early Archaic. Dart points

are described as Early Split Stem, and include the Gower type first defined at the

Youngsport Site (Shafer 1963). Johnson has determined the period was relatively moist

(Johnson 1995:Figure 35), while Collins shows it as fairly dry (Collins 1995:Table 2). Both

indicate that the beginning and end of the period were opposite what they showed for the

majority, i.e., a peak of either dryness or wetness at about the middle of the period.

Evidence suggest there were no bison (Collins 1995:383).

The question of bison presence or absence is very significant for understanding

human behavior. Bison, and to a lesser degree antelope, prefer open grasslands and

prairies, and are also social animals, traveling in large herds. The habits of these large

bodied mammals can be contrasted with the largely solitary habits of woodland preferring

deer. In most cases bison would be considered to have high return rates, tempered to some

extent by high processing costs. The results would be evident in scheduling, mobility, and

technology of prehistoric people. In general, bison could be expected in tall grass prairies

as opposed to, for instance, oak savannas. Increases in available moisture favors tall grass

over short grass, but also can result in replacement of grasslands by woods. Johnson

suggests that bison favored dry conditions in Central Texas (Johnson 1995:86). Collins

indicates bison were present in both wet and dry conditions, and it is difficult to derive any

patterns from his projected data (Collins 1995:Table 2). The strongest correlation is

between moisture loving microfauna at Halls Cave and a long period of bison presence

through the Late Archaic. At other times bison are seen when all other indicators are of dry

conditions. Perhaps the best explanation comes from Ellis et al.’s (1995) discussion of

environmental diversity. Differential change on a micro or meso scale favored bison

presence or absence on a scale too fine grained to be reasonably compared with broader

climatic shifts.

The Middle Archaic shows climatic conditions of Collins and Johnson coming into

fairly close alignment. Both agree that there was an initial period of fairly mesic conditions

followed by a period of drying. Johnson sees a fairly mild and slow paced change, while

Collins sees an almost catastrophic drought. Regardless, it is at this time that rock features,

designed in the Early Archaic for efficient control of fire-produced heat, expand in function

and complexity, coinciding with a spread of xerophytes from the west due to drying

conditions, and resulting in the burned rock middens that begin to be seen (or at least are

more common) during the end of the Middle Archaic (Collins 1995:384, Prewitt 1991:26).

Projectiles in the first part of this period are thin, broad-bladed Bell/Andice/Calf

Creek types, deeply notched points that are believed to have been used both for hunting

based on impact breaks, and as knives, as seen in microwear analysis. This is consistent

with a specialized hunting economy, and the apparent bison presence at that time would be

an obvious target of a multipurpose projectile/knife (Collins 1995:384). The disappearance

of bison coincides with the replacement of these types with narrow, thick, heavy Travis and

Nolan points. Johnson sees precursors of the bison tool assemblage coming in from the

Plains, and precursors of these latter points perhaps from the Lower Pecos, in the form of

Pandale points (Johnson 1995:88). This is suggestive, as the Plains would of course have

had bison, while they were largely absent in the Lower Pecos. Perhaps the new style was

more efficient for the newly high-ranked deer, which would surely have replaced bison as

the preferred meat source. Toolkits in general became more diverse, as diet breadth

widened and generalization became necessary in order to effectively intensify the use and

processing of lower ranked food sources (Prewitt 1981:73).

The Late Archaic, as noted earlier, is divided into subperiods I and II. The first

portion saw a continuation of the dry period initiated earlier, and burned rock midden

accumulations peaked at this time. The Bulverde point, although in some respects similar

in form to Travis/Nolan points, is seen, at least by Johnson, to be a distinct technological

break, and again to have apparent influences from the northeast and Plains regions (Johnson

1995:89-90). It is this break combined with a continuity seen in succeeding Pedernales

types, as well as the extent of burned rock midden accumulations that has resulted in this

major reordering of this portion of the Archaic.

Also appearing about this time was the Marcos-style point, another broad bladed

point with deep corner or side notching, similar in some respects to the Pedernales, at least

in width of blade. It is at this time that Late Archaic I shifts to Late Archaic II, and the

climate seems to become much moister. Apparently bison are present throughout most of

the Late Archaic, even as narrow bladed Ensor/Fairland points begin replacing the broader

Marcos/Williams/Marshalls.

One interesting way of explaining this seeming discrepancy would be by having

these latter points hafted on arrows (Tomka 1998), with an underlying (but wholly

subjective) assumption that darts did not have enough penetrating power for bison and so

the emphasis was on a wide blade causing extensive hemorrhaging. The penetration of

darts was perhaps sufficient for deer if a narrower blade was used. A narrow blade

propelled by a bow, however, might have enough penetration to effectively kill a bison.

Regardless, increased moisture saw a retreat of the xerophytes, and a corresponding

decrease in the construction of burned rock middens, especially in the eastern portion of

Central Texas.

There is also evidence of increasing populations, and processing of plants other than

xerophytes is evident based on an increase in numbers of groundstone from these

components (Collins 1995:385). It is not clear what was being so extensively processed

with these implements. Acorns and grass seeds are two possibilities. Cemeteries became

more widespread, as does evidence of internecine warfare (Hall 1981:iii). Combined, these

would suggest an attachment to land and protection of resources, and also a certain increase

in environmental stress or resource depletion. As well, Johnson sees general technologies

arriving from the plains, while social variables seem to be influenced from Woodland

cultures to the east and northeast (Johnson 1995:96, 97). In short, it seems to be a time of

rapid changes in social complexity with resource intensification and a broadening of the

diet base, most likely as a response to the demands of increasingly large human

populations.

The Late Prehistoric period seems to be a continuation of Late Archaic lifeways up

until Toyah times when bison reappeared, as did a more nomadic life as well as

technologies (blades and specialized scrapers) not seen since Paleoindian times. The Late

Prehistoric period has been subdivided into two distinct intervals by Collins (1995: 385),

which correspond to Prewitt’s Neo-Archaic Austin and Toyah Phases. The early Late

Prehistoric, or Austin Phase, shows a distinct trend towards arrow points, but the Archaic

lifeways seem to persist. The late Late Prehistoric corresponds to the Toyah Phase, and

cultural remains indicate a shift back towards a hunting subsistence base. Bison apparently

became common once more in Central Texas (Collins 1995:377 Table 2, Prewitt, 1981:84),

and prehistoric peoples evidently took full advantage of that resource. This period of

course came to its conclusion shortly after the arrival of Europeans to Texas in the early

16th Century, marking the beginning of the Historic Period.

Site Setting. The study area is located in an area of Lower Cretaceous limestones

and marls (Pearl 1997). The Fort Hood area to the north has an underlying geology that

ranges from Glen Rose though Paluxy Sand, Walnut Clay, Comanche Peak Limestone and

Edwards Limestone/Kimachi Clay undifferentiated (Nordt 1992:4), all Lower Cretaceous in

age. Site 41BL116 is within the Glen Rose formation, which consists of non chert-bearing

limestone, dolomite and marl to a thickness of 380 feet (Barnes 1974). The Glen Rose

Formation has been exposed, primarily by stream downcutting, within the later

Fredricksburg Group (Pearl 1997:21), which contains Edwards Limestone, Comanche Peak

Limestone, Keys Valley Marl, Cedar Park Limestone, and Bee Cave Marl, as well as small

areas of the Georgetown Formation, with the Edwards Formation limestone apparently

containing the majority of chert (Barnes 1974).

The soils that have developed in the general area are primarily of the Speck-Tarrant-

Purves association, with a large area of the Denton-Purves association to the north, and the

location of 41BL116 very near the eastern edge of the Trinity-Frio-Bosque association,

which forms a narrow band on either side of the Lampasas River, ending very nearly at

Youngsport, where the surrounding Speck-Tarrant Purves association replaces it along the

river (Huckabee et al. 1977). Each of these associations can contain a number of differing

soil types, but are linked by similarities in occurrence, even though the individual types

may differ considerably (Huckabee et al. 1977:2). Complete descriptions of all relevant

soil types can be found in the SCA Soil Survey (Huckabee et al. 1977), so only the more

general associations and specifically relevant soil types will be discussed here.

The Speck-Denton-Purves association are shallow upland soils that are gravelly,

loamy and clayey and occur over limestone. The Denton-Purves association are shallow to

deep clayey soils over limestone, commonly associated with upland settings. The Trinity-

Bosque-Frio association are deep soils formed in alluvium and are loamy to clayey in

nature. Soils specific to 41BL116 are Frio silty clays, in which the site itself is found, and

Denton silty clays immediately adjacent, with a nearby pocket of Purves silty clay. The

Frio soil series are up to 78 inches in thickness, grade from a dark grayish-brown to brown,

and are calcareous, clayey, and somewhat alkaline. A buried A horizon is common at

about 40 inches (100 cm) in depth. There is no B horizon and the C horizon is a brown silt

calcareous clay with calcium carbonate threads and films. The soils tend to be well drained

with slow permeability, high water capacity, and slow runoff. (Huckabee et al. 1977:16).

Denton soils are dark grayish-brown to dark brown calcareous, alkaline soils to a depth of

35 inches over a 20 inch thick B horizon consisting of a dark brown silty clay, terminating

abruptly in a fractured limestone R horizon. These soils have rapid runoff and are well

drained with slow permeability and high available water capacity (Huckabee et al. 1977:13-

14). Purves soils developed out of a limestone R horizon below 14 inches and consist of

dark-brown calcareous and alkaline silty clays. These are likewise well drained soils with

slow permeability, but water capacity is low and runoff can be slow (Huckabee et al.

1977:26).

Frio soils are described as well suited for grains, grasses, legumes and herbaceous

upland plants, as well as hardwood trees, shrubs and vines. They are good for open-land

wildlife such as quail, dove, rabbit and fox, but only moderately suited for rangeland

wildlife such as deer, bobcat, raccoon and turkey. Denton soils have fair sustainability for

grains, grasses and herbaceous plants but are well suited for hardwoods, shrubs and vines.

They have fair suitability for both open-land and rangeland animal species. Purves soils do

not support grains and grasses, but have fair suitability for herbaceous plants and

hardwoods. Open-land animal suitability is poor, although rangeland animals are fairly

sustainable. Wetland environments are not supported by any of these soils (Huckabee et al.

1977:49-50).

Understanding the soil types aids in determining and understanding potential

catchment areas (Jarman et. al 1972). Bosque soils are seen near the river and Tarrant-

Purves association and Speck series soils in more upland settings. Tarrant soils are almost

identical in suitability ratings to Purves soils, while Bosque soils are similar to Frio soils.

The large areas of upland Tarrant-Purves soils are therefore most likely to harbor rangeland

animal species, herbaceous plants, hardwood trees, shrubs and vines, but not in great

frequency or abundance. The large areas of lowland/floodplain Bosque soils are well suited

to grasses, herbaceous plants, and both open and rangeland animals. There are numerous

other soil types mapped, but these are fragmented in distribution, and introduce a level of

detail too varied for the present.

The Lampasas River is the dominant drainage for the immediate vicinity, with a

basin measured at approximately 3224 square kilometers (Pearl 1997:24). The Lampasas

joins the Little River which then merges with the San Gabriel before entering the

overarching Brazos River system. Quaternary fluviatile terrace deposits and recent

alluvium are common along the Lampasas and its tributaries (Barnes 1974). Three terraces

have been identified above the modern floodplain at heights of 8 m, 10 m and 16 m above

the modern channel (Pearl 1997:26-29). The modern floodplain, at 5 m above the modern

channel is subject to flooding every second year, while the first two terraces may flood

every five to six years and every 10 to 20 years respectively, while the third terrace (T3) is

not expected to become flooded.

The geology provides the raw material from which soils develop, and helps

determine the nature of the drainage systems. Soils can be more or less favorable to certain

types of plants and animals. Climate, especially expressed as rainfall and temperature,

influences not only soil development (Huckabee et al. 1977:69), but also the types of

vegetation that can exist in a region, with the vegetation influencing the animal

communities (Krebs 1994:458, Blair 1950:93).

The climate is referred to variously as humid subtropical (Huckabee et al 1977:72)

and dry subhumid (Thornwaite, in Blair 1950:113). Annual precipitation in Texas

decreases from east to west, from a high of over 50 inches a year to a low of eight or less

(Carr 1967:4). The project area lies very near the 32 inch isocline, so rainfall averages 30-

34 inches per year. Bell County average yearly totals are 33.87 inches (Huckabee et al.

1977:72) and the 34 and 32 inch isoclines mark the eastern and western edges of the

Lampasas Cut Plains (Carr 1967:20).

Temperature, meanwhile, increases from northwest to south, with a mean annual

temperature of 54 degrees Farenheit in the extreme Panhandle to 74 degrees in the lower

Rio Grande Valley, with the project area averaging between 66 and 68 degrees (Orton

1969:887). The average warm (growing) season, based on first and last freezes, closely

follows temperature gradients, and ranges from 185 days in the northwestern portion of the

state to 320 days in the south. The 245 day cline runs directly through the project area,

indicating a warm season of between 230 and 260 days (Orton 1969:891). In Temple, the

date of the first freeze is typically November 24, while that of the last is March 10,

producing a warm season of 259 days (Orton 1969:902).

The study area falls within Blair’s (1950) Balconian province, the biotic

components of which are varied. The floral assemblage includes oak, hickory, mesquite,

elm, hackberry, pecan, cypress, and the seemingly ubiquitous juniper. Bear grass, agave

species, and even pinyon pine extend from the west into portions of the area (Blair

1950:113). There are 57 mammal species documented, 16 lizard species, and numerous

snakes, frogs, toads and amphibians (Blair 1950:114-115). Historical accounts include

mentions of bison, mustangs, and antelope in Travis and adjoining counties (Brown ca.

1900:1.35).

The vegetation regime is a mosaic of Oak-Mesquite-Juniper Parks/Woods with a

secondary component of Live Oak-Mesquite-Ashe Juniper Parks within the broader Cross

Timbers and Prairie ecological area and very near the junction of the Blackland Prairies

(McMahon et al. 1984:3, and map). Parks are defined as woody plants at least nine feet tall

growing individually or in clusters creating an 11 to 70% canopy over non-interrupted

grasses and forbs. Woods are taller, from 9 to 30 feet in height with a dense canopy of 71

to 100% and little to no midstory (McMahon et al. 1984:2). The Oak-Mesquite-Juniper

Parks/Woods are found as associations or mixtures of the larger woody species in upland

settings of the Cross Timbers and Prairies and contain blackjack, post, Texas, shin and live

oaks along with Ashe juniper, cedar elm, agarito, soapberry, sumac, hackberry, pricklypear,

persimmon, mesquite, and various grasses, especially the grama varieties such as hairy and

sideoats (McMahon et al. 1984:15). The Live Oak-Mesquite-Ashe Juniper Parks are very

similar, but somewhat more diverse, and are associated with uplands and ridge tops of the

Edwards Plateau.

Climate, soils, vegetation and topography all combine to create a region commonly

referred to as the Lampasas Cut Plain, described as “dissected limestone plateau country

with rolling hills and easterly flowing drainages” (Collins 2001:3), which has been lumped

into a larger North-Central Texas Region (Carr 1967:3). This region falls within Blair’s

Balconian and Kansan provinces, and further, represents a transition between the Edwards

Plateau, the Oak Woods (Cross Timbers), and the Prairies, is somewhat wetter than the

majority of the Edwards Plateau and has taller trees, but also contains fewer drainages and

more open grasslands (Ellis et al. 1995:405-406).

In summary, the study area is an area of varied resources, both plant and animal, has

moderate to mild temperatures, and an aridity tempered by abundant groundwater sources.

This would be an undoubtedly attractive location for prehistoric settlement and land-use

systems. The next chapter views these specific environmental aspects from a global

perspective, and a comparative approach is applied to create a model useful for

understanding cultural and social adaptations.

CHAPTER 5

AN EXERCISE IN MODEL CONSTRUCTION

Ecological Parameters

Environmental data can be used as a means of comparing regions on a global scale.

The assumption is that people react and adjust to similar environments in similar ways.

Based in large part upon Murdock (1967), and other studies with relevant data, comparative

analyses can be attempted across a wide variety of areas and cultures. By observing

patterns on a global scale a model for regional patterns can be constructed and tested.

These methods have the potential for allowing greater understanding of the archaeological

record.

Of underlying importance in model construction is the concept of productivity.

Primary productivity refers to the amount of raw biomass an environment can produce in

any given area over any period of time. Most measurements of production do not include

below-ground biomass, as this variable is very difficult to measure accurately, and so the

measure is net above-ground annual productivity (Rosenzweig 1968), also referred to as

primary production (Kelly 1995:69), or PP, specifically defined as the annual amount of

new biomass produced in one square m. (Keeley 1988:379). These raw figures, usually

measured in grams or kilograms per unit area, give a gross indication of the amount of

energy potentially available for organisms on successive trophic levels.

A problem is encountered though, in that not all of the PP is available for immediate

consumption by other organisms. This is addressed in a variety of fashions. One involves

the use of primary biomass, which is a measure of the standing amount of vegetation at any

instant in time. Interestingly, as primary biomass (PB) increases, there is a decrease in

available material for energy resource, due to more plant energy being invested in low

value growth than in reproduction, which forms the tissues most likely to provide

sustenance for organisms (Kelly 1995:121). Such PB rates are a more accurate indicator of

available resources.

Central to all these figures are the abiotic portions of the ecological system. Of

primary importance are temperature and rainfall, which combine to produce

evapotranspiration rates. Effective temperature (ET) is a measure of overall solar radiation

within a year across a particular area (Kelly 1995:66). This measure can produce a gross

scale of relative resource abundance, correlated roughly latitudinally. Rainfall, of course,

determines how much water is available to encourage plant production. Actual

evapotranspiration rates (AE), on the other hand, are a measure of how much moisture is

returned to the atmosphere through evaporation and respiration. This measure can be used

to determine PP values, as it measures both solar energy and water availability, which are

the limiting variables for successful photosynthesis (Rosenzweig 1968:73).

Evapotranspiration rates are difficult to obtain and dependent on various factors, including

the maturity, or nearness to climax, of the specific environment (Rosenzweig 1968:70).

Rosenzweig, however, states that for arid environments actual evapotranspiration is almost

identical to precipitation (Rosenzweig 1968:68).

The study area encompasses parts of three counties; Williamson, Burnet, and Bell.

Owen and Schmidly (1986) provide climatological data for the entire state, which was

divided into quadrats. The relevant areas were measured from stations in Austin, Burnet,

Gatesville, and Temple. This baseline data provided figures from which other relevant

figures were derived, and were chosen due to their relative closeness to the study area, both

in distance and in geographic location. The study area is centrally located between all four

stations, and all four stations are located either on or very near the edge of the Balcones

Escarpment.

Effective Temperature: The equation for determining effective temperature found

in Kelly (1995:66) was utilized. The high mean temperature and the low mean temperature

from the four relevant quadrats (Owen and Schmidly 1986:107, 108) were averaged (29.11

and 9.33 °C respectively), with a corresponding ET of 15.50.

Primary Productivity: Primary productivity rates are given in Owen and Schmidly

(1986:107,108). These are somewhat more variable then temperature, and generally

decreased from north and east to south and west. The mean PP figure was 1523 gm/ m2/yr.

The low figure was for the Burnet area, while the higher number was for Temple. This

appears to be more a factor of rainfall than temperature, as rainfall was more variable than

the high tempreature means (although there was an obvious difference in low mean

temperatures).

Primary Biomass: Primary biomass was calculated using the formula given in Kelly

(1995:121) for arid environments. Arid and humid environments are differentiated

primarily by ET values, and Kelly (1995:121) places the study area’s ET figures within arid

constraints. The value was 10.75 kg/ m2.

Results. The environment, based on ET values, fell between temperate desert and

tropical/subtropical desert (Kelly 1995:117) or between warm temperate and semitropical

(Binford 1980: Table 2). Blair also describes the region as arid to dry and recognizes

widespread oak, mesquite, juniper and hickory (Blair 1950:113), also referred to as woods

and parks (McMahan et al. 1984). With a warm season of around 250 days, and average

rainfall rates of around 30 inches (Orton 1969:888, 891), ET values may not be the best

means of arriving at an environmental descriptor. The study area, based on these various

data, will be described as semi-arid woodland .

When the regional ecology was placed into various models in Kelly, almost

invariably the one cultural group associated with a similar environment was the Hadza of

sub-equatorial Africa (1995:122, 128). No other foraging groups were found within the

ecological parameters being considered. This lack of broad associative data may be the

result of many hunter-gatherer groups being removed long ago from favorable temperate

environments (e.g. see Headland and Headland’s [1997] discussion of the principle of

competitive exclusion). Regardless, even such limited comparisons are valuable when

comparing global models to local realities.

The Model

Defining the ecological factors that are broadly predominant in the study area allows

construction of a global comparative model. Such variables as effective temperature,

evapotranspiration rates, primary productivity, and primary biomass allow definite

boundaries to be placed around theoretical expressions. Once global comparisons are made

groups most closely associated ecologically can be analyzed, with resulting data referenced

to produce a local model of environmental adaptations. This hypothesized settlement

pattern can then be field tested, with results, positive or negative, duly accounted for.

Perhaps of greatest value is the possibility that construction of the regional model based on

a global perspective may encourage more intensive investigations in areas or theoretical

dimensions previously under-explored by regional investigators.

Subsistence. Various lines of reasoning suggest this type of environment is more

conducive to gathering of plant materials than to primary use of hunted protein. The Hadza

rely on non-hunted resources for 65% of their subsistence base and consume no fish (Kelly

1995:131, Woodburn 1968). Based on an ET value of 15, Binford, using ethnographic data

from Murdock (1967), determined that 64% of described groups based subsistence on

greater than 60% plant foods (1990:132, Table 9). Fishing or dependence on other aquatic

resources was absent in 47% of the sample (Binford 1990:135, Table 10). Ten and 20%

dependence on aquatic resources was found in 11% and 12% of the sample, respectively,

while higher dependence rates were negligible (one group each at 30 and 40 percent;

N=14).

When division of labor is scaled against ET values, men are seen to provide

between 30 and 48% of food resources (Kelly 1995:264). ET values between 15.1 and 15.9

produced very similar results from the Great Basin and Australia (Kelly 1995:Table 7-1). If

the common assumption of men as hunters is allowed, then the result is that women are

gathering approximately 60% of the overall food resources, which further indicates

substantial dependence on gathered plant foods. A ratio of vegetable to meat subsistence of

around 70:30 indicates an energy maximizing, as opposed to time minimizing, subsistence

strategy (Belovsky 1988:332). This subsistence data has implications for social structure

and group interactions. The acquisition of calories takes precedence over producing free

time, which indicates less time is spent in family and leisure activities (at least by women).

Storage is tightly connected to subsistence and mobility strategies. Storage may be

a form of resource intensification, allowing greater sedentism (especially over winter), or it

may be incidentally based on windfalls of resource abundance. As storage increases there

are changes in group mobility patterns. Reliance on storage increases the likelihood that

groups will utilize logistical procurement strategies, and in turn, trend towards collectors as

opposed to foragers (Binford 1980:351). Rafferty (1985) recognizes pottery as a means of

storage and part of the process of intensification eventually leading to, or at least enabling,

sedentism (1985:119-120). Six groups in environments with ET figures of between 14.9

and 15.9 have minimal storage, most often using baskets to store dried nuts and seeds

(Binford 1990:142, Table 14). Based on latitude and population densities Keeley

determined storage values would be low, with value codes of 0-2 on a scale of 5

(1988:385).

Mobility. Based on an ET value of 15, (there were only three groups presented for

ET values of 16), Binford classifies foraging groups living in similar environments as

primarily semi-nomadic (1990:131, Table 8), represented by over 78% of the 14 groups

within that ET range. No groups were found to be fully sedentary, while 14.3% were fully

nomadic, and the remainder semi-sedentary.

Kelly plotted primary biomass figures against residential mobility patterns, and

when the Hadza, this region’s closest analog, are evaluated, they were shown to move about

27 times per year (1983:281). This is an outlying figure, however, falling well outside the

curve formed by multiple cross-cultural comparisons, which indicates a residential shift of

perhaps five times per year, based on this study area’s PB figure of 10.75 kg/ m2 (Kelly

1995:122). This drastic difference is undoubtedly due to confounding variables in the

environments, possibly such as water and secondary biomass availability, and also resource

intensification procedures such as storage or even horticulture.

What remains, then, is to produce a value based on the study region’s ecological

parameters. As the study area has been described as temperate, but arid woodland, rather

than the tropical desert of the Hadza, and the PB figures are relatively low, indicating

moderately high levels of available plant food resources, and seasonal variability indicates

concomitant variable resource availability, local groups would best be described as semi-

nomadic, with the high rate of moves by the Hadza of 27 times per year tempered by the

low figure of five moves per year. This high spread of potential mobility rates is justified

by the aforementioned lack of direct ethnographic analogies in similar environments (i.e.

there is little direct comparative data), and may be one of the more testable portions of the

overall model.

Territory and Territoriality. Territory is here defined as how much land a group will

encounter in any given year. One method of determining territory would be to simply

multiply number of moves by distance moved to develop a linear figure. This of course

would not be an accurate measure of actual territory as defined by land forms and resources

the mobility was designed to encompass. The Hadza, for instance, cover a total area of

2520 square km (Kelly 1995:114), a figure not readily discernible from previously supplied

data. The figure for the Hadza, then, can be assumed to be the high end of the territory

range for the study area, primarily due to lower levels of mobility as noted above.

Subsistence strategies also provide clues to territory size. Increased dependence on

hunted resources increases range (Kelly 1995:130). As already established, the study area

is expected to receive 30-40 % of food resources from hunting. Out of 10 groups within

this range, eight had territories smaller than the Hadza, with the majority maintaining

procurement areas of 100-1000 square kilometers. The Hadza once again provide an outlier

figure which will provide an outer limit, while other variables are considered and used to

temper the extremes.

Territoriality is the cultural awareness of who the land belongs to. This sense of

belongingness is often expressed in defensiveness, which is a willingness to risk the costs

of defending an area in order to reap assumed benefits (Kelly 1995:189). Empirical figures

were not used by Kelly (1995:190), but an intuitive overview of the study area suggests that

low resource density coupled with low resource predictability would result in relatively

greater dispersion and mobility (than to other groups in dissimilar environments), and of

interest here, lessened territoriality (Kelly 1995:190, Figure 5-4). This may be partially

supported by rainfall data. Precipitation rates peak in May and September, with

approximately 4 and 3 inches each of these months, respectively. Much of the rest of the

year receives less than two inches in any given month (Carr 1967:7). Such variability may

well affect distributions and predictability of resources. So, on a cost/benefit analysis, the

potential cost of defending a territory is not worth the fairly low yield within any given

area. As long as populations are free to move to new locales in such environments,

defensive strategies should remain low and resource intensification should be unnecessary.

Group size. The Hadza are documented as maintaining group size between 20 and

60 persons (Kelly 1995:211, Keeley 1988:382). They furthermore have a population

density of 15 persons per 100 square kilometers (Kelly 1995:226). A group of 20 persons

would therefore be expected to utilize 130 square km, while the larger extreme, 60 persons,

would inhabit close to 400 square km. In one of the few direct mentions to groups close to

the study area, the Karankawa, found further to the south, had a population density of 19 to

42 persons per 100 square kilometers (Kelly 1995:Table 6-4, Keeley 19888:383), a figure

which falls well within the Hadza model. It should be noted that Kelly’s data places the

Karankawa in temperate forests (ignoring the coastal plain environment they may be more

closely associated with [e.g. Patterson 1995, Gatschet 1891]) while the Hadza’s

environment is described as tropical/subtropical desert (Kelly 1995:225, 226).

Social organization. Social organization is a concept which can only be approached

with extreme caution, especially with the data currently being utilized. The ephemeral

nature of hunter-gatherer sites in the archaeological record makes such applications very

difficult to test. It is perhaps for this reason that relatively little comparative data is offered.

The strongest line of evidence would be in the observed fact that men provide between 30

and 48 % of food in similar regions with identical ET values (the Great Basin and Western

Australia), while with the Hadza, with a slightly higher ET value, men produce only 20% of

the subsistence base (Kelly 1995:264). These figures reinforce concepts of a male-

dominated society. If the assumption of low resource predictability is continued, bilocal

post marital residence is the most likely scenario for the study area, as there is no advantage

for a man to remain in his native territory, but there may be an advantage to moving for a

period of time to his wife’s locale, thus increasing his overall knowledge of regional

resources (Kelly 1995:272-273).

It is probably safe to assume the prehistoric people of the study area were simple, as

opposed to complex, foragers. Such variables as unpredictable environment, terrestrial,

largely game-based diet, relatively high residential mobility, low population densities, little

food storage, and limited territoriality all are indicators of such groups. Extrapolating from

the known variables assumptions can be made about other aspects of foraging life in the

study area. Such groups likely would have been egalitarian with little to no corporate

structure, specialization would have been limited to the elderly, competitiveness in resource

acquisition would have been unheard of, while resources would have been diffused widely.

Accumulated wealth would have been extremely rare, as would have been warfare and

slavery (Kelly 1995:294).

Shelter. Binford (1980, 1990) has provided data suitable for model construction,

some testable, some not. Assuming the group in question leads a semi-nomadic existence,

several assumptions can be made about housing. Such people would have been most likely

to have resided in semi-circular houses (69% of 93 groups) (Binford 1990:123). Of interest

is that no semi-nomadic groups were found to be living in circular houses, which were

reserved exclusively for fully nomadic peoples, and less than 13% of those. Both fully and

semi-nomadic people would have probably placed their houses directly on the ground

surface, as opposed to semi-subterranean or raised earth structures (Binford 1990:124). It is

also likely, especially among the semi-nomadic groups, that some sort of alternative

(seasonal) housing would have been utilized. Such housing would have had a roof and side

made of the same material, most likely grass, as would have the primary (winter?) housing

(Binford 1990:125-128). Hides would be the more likely roofing ( and therefore siding )

material for the primary houses of fully nomadic groups (Binford 1990:126). Housing

portability would have been fairly low. The presence of alternative housing, a relative lack

of dependence on hunted foods, and readily available natural resources would not have led

to transporting houses between locations (Binford 1990:129). The expected house

structures would most likely have been used on a seasonal, repetitive basis.

The Local Model

The global information provided above can now be synthesized into a local model

based on global patterns. This model can then be tested against the known archaeological

record.

Local prehistoric people were semi-nomadic groups of up to 60 persons covering up

to 400 square km of semiarid woodland. They would have moved residences up to 27

times a year, with an average distance of eight km between locations. Total territory

covered was up to 2500 square km, with between 19 and 42 persons per 100 square km in

density. They would have subsisted on plant resources for 65% of their caloric intake, and

would have used almost no aquatic resources. Warfare would have been limited or

nonexistent. Men would have provided most of the hunted meat, while women would have

provided most of the food. The social structure would have been egalitarian, with little

competition for resources and very little specialization. Post-marital residence was

probably bilocal, although inheritance rules may well have been patrilineal. They would

most likely have lived in semi-circular houses covered entirely with grass, with some

structural discontinuities between summer and winter houses. They did not take their

houses with them when they moved. Storage was probably limited to incidental

accumulations of seasonally abundant nuts and grains which were dried and kept in baskets,

pots, or subsurface pits.

If the model is taken to its extreme, what follows is a picture of prehistoric people

gathering along river and creek banks in early fall and establishing or repairing fairly

substantial structures. They would stay at these sites for one to four months, and typically

have good success at exploiting abundant faunal and floral resources. As spring

approached they would begin to make logistical forays, most likely testing various patches

for abundance. Then, as various resources either reached fruition or declined in abundance,

residential moves were made to accommodate the changing environment. Summer months

may have necessitated more frequent moves, as any stores would be exhausted as available

resources dwindled. Chances are good these people followed well established paths which

took them in a circular route over a changing landscape, never, however, far from water.

Fall was a welcome respite as they returned to winter haunts, waiting to enjoy the crops of

nuts, grains, and seeds, as well as the camaraderie of friends and family last seen some

months previously.

This idealized interpretation suggests that there may be various archaeological

signatures that could be used to support or negate its alternative aspects. Because it is

largely subsistence based, evidence from prehistoric subsistence activities might be the

most direct evidence. Site 41BL116 contains high numbers of the land snail Rabdotus. If

its presence can be shown to be the result of intentional foraging behavior, it may provide

some of the data that might be used to test portions of the model. The following two

chapters follow various lines of reasoning to suggest that snails were consumed at the site.

It will then be possible to pursue these larger questions.

CHAPTER 6

QUANTIFYING SNAIL POPULATIONS

It should be remembered here that there are two distinct, but not entirely unrelated,

research questions. The first, which is discussed in the present chapter, involves

determining if Rabdotus snails from an archaeological site (in this case 41BL116) can be

distinguished from naturally occurring snail populations. If on-site snails exhibit a

population structure that can be shown to be distinct from off-site populations, then a link

between human occupations and snail presence will be supported. Such a link would

suggest, but certainly not prove, that snails were a dietary item.

One method of supporting the hypothesis would be to determine if on-site snails

contained a lower percentage of juveniles than off-site, or natural populations. The

assumption here is that human foragers would be more likely to gather the larger and

presumably more visible adults, with a resulting gathered population therefore containing a

greater number of larger specimens. If a number of juveniles comparable to natural

populations, that is, smaller snails, are found within site deposits, it would run counter to

optimization expectations, and a direct cultural explanation for snail presence could be

largely discounted.

Another approach is by comparing densities of snails from on-site and near-site

deposits. Should densities be similar, a cultural explanation would again be discounted. If

there are considerably more snails in cultural deposits than in nearby non-cultural deposits

in identical environmental settings, then the snails could be considered the result of direct

(gathering) or indirect (the commensal scavenger theory) cultural processes. If on-site

snails are found to be significantly larger than natural populations and also found in greater

quantities, human gathering is strongly supported.

Once human gathering is supported and becomes a working assumption, the

concepts of optimal foraging theory can be applied. This requires knowledge of caloric and

nutritional values for the food items in question, and thus requires live snails for analysis.

The gathering of live snails leads naturally into additional analyses from which net return

rates can be determined, which is the second research question, addressed in Chapter 7.

The methodology involved in this project may be subject to various complaints.

These might include those mentioned previously, complaints that may be lodged against

optimal foraging theory and models. Another potentially troubling aspect of the research to

some might be the assumptions forced by the use of modern snail samples to extrapolate to

prehistoric populations. Without detailed knowledge of environmental factors it becomes

difficult to state emphatically that a modern sample is representative of non-extant

populations.

This is a recognized issue in archaeology, and one that has been addressed, perhaps

most usefully, through the concept of middle range theory. Bettinger describes middle

range theory as a method of “developing better links between theory and data through

theories of limited sets” (1987:124), where “limited sets” refer to limited sets of behavior

that can be contrasted with general behavioral sets that lead to “highly abstract” and often

“difficult” higher order theory (Bettinger 1987:121).

Binford, who Bettinger acknowledges as one of the leaders in middle range

applications (Bettinger 1987:125), became interested in faunal assemblages at human-

hominid sites with an applied focus on early sites in Europe, Asia, and Africa (Binford

1981). He was concerned that assumptions of human activity had been too broadly applied,

resulting in false interpretation of early human activities. He felt the way to clarify these

issues was through more clearly defining human activity through recognizing its products in

the faunal record (Binford 1981:7). Because an archaeological site rests within geological

deposits, the association between human and naturally introduced materials cannot be

casually assumed (Binford 1981:18). The archaeologist works in real time, and is therefore

attempting to interpret the past through an empirical frame grounded in the present (Binford

1981:22). This requires a “reasoning process”—the middle range—an assumption of

uniformitarian processes (Binford 1981:22).

By accepting the assumption, it then becomes possible to use “actualistic studies” in

order to apply the knowledge gained from living systems to those that can no longer be

studied in fact, meanwhile realizing that the assumptions may be proved false (Binford

1981:27). However, present day living systems that also existed in the past “warrant” such

uniformitarian assumptions, and by continued middle range testing in various realms such

assumptions may be increasingly supported (Binford 1981:28, 29).

This can be easily seen as applicable to the controlled collections of snails, both

living and dead, in order to determine various aspects of snail ecology and how human

interactions with snail populations might result in differential community structure,

especially within death assemblages. Binford argues that testing must be accomplished in

this manner, and that the middle range theory must be divorced from more general theory,

primarily because of the preconceived, paradigmatic ideas such theory imposes. Once the

middle range is fully established, it can then be applied to the archaeological record in

pursuit of higher order theory (Binford 1981:29). In the present case, snail research can be

carried out within an optimal foraging perspective, which Bettinger indicates falls within

his “limited sets” (Bettinger 1987), but not necessarily, from Binford’s perspective,

structured explicitly within a framework of evolutionary ecology. Once the hypothesized

optimality aspects of snail procurement are established and supported, however, it is then

possible to take that body of data and apply it to the bigger model, to find that particular

aspect of behavior and place it in the larger cultural system.

This is a reasonable and compelling argument, but one that Bettinger calls the “myth

of middle range theory” (Bettinger 1987:127). Although Bettinger is a strong supporter of

the concept, he feels that it cannot be separated from more general “sets” of knowledge and

theory. Although observations of dynamic systems are often the focus of middle range

research, it is not the extant system itself that is of interest, but the “processes and

principles” that can be applied in a more general sense that are of concern. Removing the

limited sets of data from more general contexts relegates the data to the observational level,

when it is the underlying logic that is of importance (Bettinger 1987:129-130). Such logic

may be proven true or false, but either outcome “can have true implications” (Bettinger

1987:131). It is through open ended research that recognizes an intrinsic link between

limited and general sets that progress in both arenas can be made.

The differences are actually minimal, and seem to relate more to issues of timing

than overall approach. Binford is essentially attempting to remove bias, while Bettinger

wants to keep the research grounded and focused. Both are interested in furthering the

development of the greater science, and both feel that pursuing the open-ended, actualistic

studies that middle range theory affords will help accomplish that goal.

The present study probably leans more towards Bettinger’s interpretation. The

snails have been approached through a fairly explicit framework of optimization strategies

couched in the larger concerns of energy studies, ultimately shaped by concepts of

evolutionary ecology. At the same time, the empirically based aspect of the study has been

just that; an inductive exercise designed to determine the quantifiable differences between

natural and potential artificial snail assemblages, as well as determining the nutritional

value of snails. These data feed back into the interpretive system, and are not necessarily

limited to one or another general theory. Those who may choose to utilize the information

may apply it towards goals completely separate from those of evolutionary ecology. Others

may determine that snails were not uniformly structured throughout the prehistoric past,

and conclude that the results presented here are inaccurate. That is also acceptable, because

the present study will have been used, its approaches tested, and the information presented

built upon, just as this study has built upon previous work, both limited and general in

scope. In the meantime, this particular aspect of human subsistence can be pieced into what

is known about other patterns of adaptation, and to some extent add both depth and breadth

to our overall knowledge.

Experimental gathering exercises are an integral portion of this study. The site

assemblage required comparison with a naturally occurring death assemblage in order to

determine population dynamics. The collection of live snails was performed in order not

only to attain a nutritional analysis, but also to mimic foraging behavior and thus establish

energy expenditure rates against which the caloric and food value of the gathered snails

could be gauged.

A number of collecting episodes were required to gather the data that are presented

below. These various collections were performed at different times for different purposes,

some of which were adjusted as the project progressed. These collection episodes are

summarized below in order to create a frame of reference for later discussions. They are

described in more detail later when relevant or necessary.

Welder Wildlife Foundation: On May 11-13, 2001 efforts were made to identify

and collect living colonies of Rabdotus species snails at the Welder Wildlife Foundation

(WWF) in San Patricio County near Sinton, Texas. Although living snails were scarce, a

number of transects were established that allowed subfossil shell (defined here as shells

representing potentially extant, as opposed to extinct populations) to be collected. A total

of 2100 square m were surveyed with 541 shells collected in a total of 101.5 minutes. This

will be referred to as the WWF collection.

Brackenridge Field Laboratory 1: On June 22, 2001, a visit was made to the

Brackenridge Field laboratory (BFL) in Austin, Texas. There had been substantial rain

throughout the night, but it had decreased and largely ended by morning. As snails were

expected a time trial process was established and in place. This involved determining both

search and pursuit times, with search determined as time between patches, and pursuit the

time within the patch. Search times were later determined to be problematic, and are not

used in the project. Once the patch was felt to be exhausted, its area was determined by

paced measurement, and a new search was initiated. A total of five patches were exploited,

with a total of 247 snails gathered from 4200 square m with a total pursuit time of 61

minutes. This will be referred to as the BFL1 collection.

Brackenridge Field Laboratory 2: On July 18, 2001 a return visit was made to the

BFL in order to make controlled collections of subfossil Rabdotus snail shells. The purpose

was to collect a sample representing a natural death assemblage. This was accomplished by

concentrating on 100% collection of all Rabdotus shells encountered. Approximately 29

patches, chosen on the basis of observed presence of more than one Rabdotus shell, were

searched within a 200 m sq area. The patch sizes were intentionally left very small

(between 20 and 50 cm in diameter) in order to assure maximum recovery, and only the

very smallest snails would have escaped observation. Once a collection was begun, it

progressed in stages, with first the visible surface shells being collected, followed by

careful hand sifting of the leaf litter and decayed vegetation, slowly clearing it away until

the bare soil was exposed. In most cases the soil was then carefully probed with a hand tool

to a depth of 1-3 cm. All observed Rabdotus were collected. A total of 343 snails were

collected within an estimated 11.5 m sq. This will be referred to as the BFL2 collection.

Off-Site Shovel Tests: On July 14, 2001, a series of shovel tests were excavated in

the vicinity of 41BL116 in order to compare the number and population structure with those

collected from the site itself. The shovel tests were 30 cm in diameter (700 square cm)

holes excavated in arbitrary 20 cm levels. Shovel tests that encountered dense cultural

material were terminated. Those that encountered relatively sparse cultural material were

continued under the assumption that there would be a certain amount of “noise” due either

to natural or cultural formation processes. Five shovel tests excavated to 80 cm in depth

recovered a total of 59 shells. This will be referred to as the Off-Site ST collection.

Off-Site Background Collection: On August 11, 2001, a surface collection in the

vicinity of 41BL116 was made to compare with the natural death assemblage as obtained

previously with the BFL2 collection. It resulted in the collection of 97 shells. Collection

here was problematic (discussed below) and times and areas were not recorded. This will

be referred to as the Off-Site2 Collection.

The Site Sample: Snails from the archaeological test column were collected between

February 27, 2000 and December 30, 2000. One hundred percent collection from 1/4 and

1/8 inch screens was attempted. Snails from the site were quantified in various ways as the

research progressed. The first priority was counting them. Due to various constraints,

counting each individual shell was not attempted. Instead, a standardized measure was

obtained through use of a container that was known to hold a relatively constant number of

shells. This number was obtained through a series of tests, in which the container was

filled, and then the contents counted. This was repeated several times until it was felt a

satisfactory average had been achieved. This procedure was used for shells recovered from

both 1/4 inch and 1/8 inch screens. For the 1/4 inch field sort, the shells were first

rescreened through nested 1/2 inch and 1/4 inch screens. The 1/2 inch material was counted

by way of a container holding 50 shells, and the 1/4 inch material in one holding 25 shells.

Each container fill was counted and then multiplied by 50 or 25, as appropriate. Any shells

left over from either sort were counted individually and added to the total. Shell from the

1/8 inch screen was counted using the same method, but with a smaller container that held

35 shells. The majority of specimens from the 1/8 inch sort were incomplete spire portions.

Shell collection was based on collection of either whole individuals or the spire

portion of broken shells. It was in this manner that a Minimum Number of Individuals

(MNI) was attained. As counting progressed, it was noticed that many of the larger shells

lacked the spire portion. This most likely resulted in an artificially inflated count. Options

included counting only apertural (the shell opening) sections, but these are fragile, and it

was felt to be an unreasonable alternative. Similarly, strict adherence to a complete or spire

only policy would result in the unnecessary removal of otherwise diagnostic shells from the

analytical assemblage. A rather informal review of the collection indicated that the number

of larger individuals lacking spires was relatively minor, leading to the conclusion that

although the Rabdotus counts were probably somewhat higher than in actuality, the

difference was not substantial, and more importantly, was consistent across levels. The

same logic is applied to potential complaints regarding the actual counting method. What

may be lacking in precision is relatively minor, and once more, is consistent across levels.

Site Collection 1: The first analysis involved obtaining a randomly derived 5%

sample from each of 21 levels in the test column. The snails were initially selected in order

to determine representative counts and measurements on adults and juveniles from the test

column, but once it was determined that the sample size for juveniles was too small to be

statistically valid, it was used instead as a baseline index of width-to-height ratio

representing the general site population. This sample consists of 321 shells and is referred

to as the 5% sample.

Site Collection 2: The second analysis on the archaeological column sample was a

more rigorous effort at determining adult to juvenile ratios effected by randomly selecting

six levels and pulling 240 shells from each. These were analyzed for juveniles, which were

pulled and measured. A closely matching number of adults were then randomly pulled and

measured as well. This resulted in 365 shells receiving measurements. The purpose for the

50/50 ratio of adults and juveniles receiving measurement is based on the BFL2 collection

from which a natural death assemblage of approximately 50% was derived (described

below). This sample is referred to as the 50/50 Site sample.

Number of Juveniles

As mentioned, the numbers of juveniles will be used to create class breaks based on

relative size. As will be shown below, it is not possible to directly compare different

populations of snails based on absolute size because of overlaps in characteristics between

populations in different environments and between different species within the Rabdotus

genus. However, by looking at the relationships between adults and juveniles, expressed as

a width-to-height ratio, a relative relationship can be established between populations

representing different species and environmental zones. But first it is necessary to be able

to distinguish between adults and juveniles.

What does a juvenile look like? When attempting to divide Rabdotus into age

categories it is tempting to rely on size as a determining factor. As will be shown, and is

documented elsewhere (Brown 1999), there is considerable overlap in the width (diameter)

and height in adult and juvenile populations. Brown (1999:233-234) has compiled a

number of indicators useful for determining juvenile status. Figure 2 presents three shells

representing three stages of development.

Figure 2 Comparing adult and juvenile Rabdotus. Numbers 1-5 are explained in text.

Numbers 6 and 7 illustrate measurement points for width (diameter) and height,

respectively. Scale in cm.

Specimen a is a fully developed adult. Specimen b is an adolescent, retaining some

juvenile characteristics, while Specimen c is more clearly a juvenile. The most telling

aspect of a juvenile is its carina (1), a ridge formed on the basal whorl below which new

shell develops. This carina is still visible in Specimen b (2), but absent in Specimen a. The

apertural lip of the adult (3) is slightly reflected, and at the point of reflection another ridge

has developed, the apertural ridge, which are also called varices. This is seen under

development in Specimen b (4), but is lacking in Specimen c, where the shell at the opening

is sharp-edged and unreflected. The signature of a fully developed adult is known as a

callus, a thicker portion of shell which often displays a distinctive sheen (Specimen a: 5).

Other characteristics include thicker shells and a lower width to height ratio for the body,

but a higher aperture height to total shell height ratio. Coloration is also more pronounced

in younger individuals. Based on Goodfriend (1986:214, in Brown 1999:234) the presence

or absence of a carina is the most telling aspect of the juvenile (or adolescent). It was this

criterion that was most useful when sorting the samples in the present study, (and referring

again to Figure a), both Specimens b and c would have been classed as juveniles.

This approach was not without difficulty. Some individuals were so small in a

relative sense that it was felt certain they were actually juveniles. In such cases the lip was

examined, presence or absence of a callus was determined, and an often fairly subjective

decision was made as to which category to place the shell in. At times relatively large

shells were seen to have carinas, and the same criteria were applied. In some instances

obviously mature shells exhibited irregular bulges on the basal whorls that to some extent

resemble carinas. These were determined to be either a function of age or perhaps the

result of distortion due to burial. These individuals all had calluses and were easily

identified as adults.

More troubling was the incomplete mature adults. These were shells that were

lacking basal whorls, often creating the impression of a thin-lipped carina-endowed

individual. The interior whorls of the shell build upon each other in step-like fashion, albeit

as a spiral. Destruction of later whorls reveal a ridge which closely resembles a carina.

This aspect of snail analysis is perhaps one that might prove most confusing to the analyst.

It was only through experience that implications of remnant shell left on the apparent basal

whorl and sudden and unusual changes in coloration from above and below the apparent

carina that relative confidence as to recognition of these specimens as adults was achieved.

Regardless, a level of subjectivity was often present, and must be accepted.

What Does A Natural Population Look Like?

The natural population is later compared with the site population, based on the ratio

of adults to juveniles found within the death assemblage. The first step is to determine the

ratio of adults to juveniles in a natural death assemblage.

Determining the Ratio of Juveniles in a Natural Population. The BFL2 sample was

divided into adult and juvenile groups, and the height and width of each was recorded. The

snails were further sorted through a standard 1/4 inch screen. A total of 315 snails

remained behind. Of these, 171, or 54%, were juveniles. The 28 snails that fell through the

1/4 inch screen were all juveniles. When these are factored in, the percentage of juveniles

rises to 58%. Following Drennan, the error range of the percentage at the 95% confidence

level was determined for the 315 snails from the 1/4 inch screen (Drennan 1996:140) The

sample indicates that a natural death assemblage collected at the Brackenridge Field

Laboratory and sorted through 1/4 inch screen consists of 54% juveniles ± 5.6% (at the

95% confidence level, d.f. = 120), allowing an assumption to be made about Rabdotus

populations in general, that is a natural death assemblage (gathered from 1/4 inch screen)

consists of between 48 and 60 % juveniles (54%±5.6%). In order to simplify the procedure

and make the results more widely applicable, only the shells from the 1/4 inch screen

(n=315) were used in later calculations.

Comparing On-Site And Off-Site Samples: Quantities. Once the natural death

assemblage was established it was possible to compare it with the site collection. First,

however, it was necessary to determine if the quantities of shell within the site were

representative of those outside the site’s boundaries. If the density of snails were similar in

both cultural and non cultural contexts, natural, rather than human agents would be

indicated. This comparison was accomplished through a series of shovel tests designed to

recover snails in contexts lacking cultural material (Off-Site STs collection).

Out of five tests, three were completed based on lack of cultural material, therefore

indicating cultural deposits were unlikely. Snail counts were qualitatively low. In order to

obtain a more precise comparison, the cubic values of the shovel tests were compared with

those of the site column. It was determined that the volume of a single 5 cm level (50,000

cubic cm) from the 1 x 1 m test column was 3.57 times the volume of 20 cm level from a

shovel test (14,000 cubic cm). This figure was used as a constant which was applied to the

snail variable. The highest snail recovery from any single twenty cm level from the shovel

tests units was 34 snails, that when corrected for volume, would represent 121 snails in a 5

cm level from a 1 x 1 m square (5000 cubic cm). Numbers from the four 5 cm levels that

are at corresponding depths within the 1 x 1 m column were between 546 and 903 (per

5000 cubic cm). This indicates a real difference between the Rabdotus counts within the

site and at its borders.

This strongly suggests that the snails within the test column are not the result of drift

deposits intermingled with human activity areas and that there is a close association

between human activity and Rabdotus presence. What remains unknown is whether these

snails are natural populations attracted to human campsites, or if they were purposefully

gathered by humans for assumed consumption and then discarded.

Comparing On-Site And Off-Site Samples: Quantifying Juveniles. Although

juveniles and their relative proportions to adults are the focus, it is not really the number of

juveniles that are at issue. It is not suggested that they were being selected against because

they were juveniles, but rather, because of their smaller size. Quantifying juveniles, then, is

actually a proxy for obtaining size data. One means of looking at size has already been

mentioned, recording height and width. This can be somewhat useful, but there is

considerable overlap between Rabdotus species (Fullington and Pratt 1974), and also

between adults and juveniles. Figure 3 shows boxplots comparing median dimensions and

interquartile ranges between adults and juveniles from the BFL2 collections.

There is considerable overlap between these measurement classes. Furthermore,

absolute measurements are of no value when comparing different species, such as appear to

be present within the site sample. More useful is a width-to-height ratio, obtained by

dividing the height into the width of each specimen. This is an established method useful

for differentiating the different species (Fullington and Pratt 1974). It was also tested as a

means of looking at the differences between adults and juveniles, and therefore, size

classes.

173142173142N =HeightJuvHeightAdultWidthJuvWidthAdult

11012920

Figure 3. Comparing height and width between adults and juveniles from 315 shells sorted

out of 1/4 inch screen from the BFL2 collection.

The 50/50 Site Sample becomes a modeled natural population (MNP), drawn from

the actual site population (ASP). Each member of the 50/50 Site Sample was sorted

according to juvenile or adult status, and width and height of each was recorded. This

provided a width-to-height index approximating a natural death assemblage (from BFL2)

derived from the site sample, and was also a control against which the actual site population

could be tested. (The actual percentage of juveniles from each of the six levels comprising

the 50/50 Site Sample was between 8.75 and 18%, depending on level, with a resulting

mean percentage of juveniles of 12.5%.)

A comparative sample from each of 21 levels was also measured for width and

height, although not separated by age categories (the 5% Sample). These measurements

represent the ASP, and are compared with the MNP. To reiterate, the 5% sample (ASP)

represents the site assemblage, and the 50/50 sample (MNP) represents a natural death

assemblage as supported by the BFL2 collection. The MNP is necessary in order to

maintain consistency across populations, as it would be inappropriate to compare the site’s

snail measurements with those of the BFL.

The utility of the width-to-height ratio was first tested with the BFL2 sample. The

error bars in Figure 4 indicate a significant (p=.05) difference between mean width-to-

height ratios of adult and juvenile populations.

142142N =

Width/HeightJuvWidth/HeightAdult

Figure 4. Control BFL2 sample approximating a 50% natural death assemblage. Note that

the number of juveniles was adjusted from 173 to 142 in order to create a true 50%

comparative ratio. The total BFL2 sample is compared below.

Next, by combining all 284 shells, a total mean width-to-height ratio was

established (Figure 5). This allows a comparison between the indexes established for adults

and juveniles and the total population, thus creating a mean value that is derived from a

population consisting of equal proportions of adults and juveniles. As Figure 5 illustrates,

this mean is significantly different than either from adults or juveniles.

284142142N =50%TestWidth/HeightJuvWidth/HeightAdult

Figure 5. Control BFL2 sample approximating a 50% natural death assemblage, with the

combined mean of the adult and juvenile populations added.

The 50% portion of the BFL2 sample was next compared with the total mean of all

315 shells gathered from the 1/4 inch screen for the same collection. Figure 6 allows a

comparison between a 50% natural death assemblage and that actually encountered.

315284142142N =

TotalMean50%TestWidth/HeightJuvWidth/HeightAdult

Figure 6. Control BFL2 sample approximating a 50% natural death assemblage with actual

death assemblage from 1/4 inch screen sort added and compared to the combined mean of

the adult and juvenile populations (TotalMean).

Although somewhat different, it can be seen that both the 50% experimental sample

mean and the total mean from the BFL2 collection are weighted slightly towards the

juvenile ratio. The 50% test is equivalent to the MNP, and the Total Mean is equivalent to

the ASP, if the method was being applied to a site assemblage. In short, a natural

population, separated on the basis of observed juveniles, should have statistically

significant differences between adult and juvenile width-to-height ratios, with an overall

mean falling between, and itself statistically significant, with no statistically observable

difference between a modeled and an actual assemblage.

This methodology was applied to the site data. Figure 7 explores the data obtained

from the 50/50 Site Sample (MNP) described above.

365183182N =TotalMeanWidth/HeightJuvWidth/HeightAdult

Figure 7. The 50/50 Site Sample (Modeled Natural Population), comparing adult, juvenile,

and total mean width-to-height ratios.

Although the actual sample means are different from the BFL2 collection, the

relationships are the same. Adults and juveniles are statistically separate from each other

and from the mean of the total population. This is what the population should look like if it

was naturally occurring. The MNP, however, must be compared to the assemblage that is

representative of the actual site population. In Figure 8, the 5% Site Sample (ASP) is

added, and compared against the MNP.

321365183182N =5%SampleMeanTotalMeanWidth/Height JuvWidth/HeightAdult

Figure 8. The 50/50 Site Sample (MNP) as in Figure 7, with the 5% Site Sample

representing the Actual Site Population (ASP) added.

The 5% sample is statistically almost indistinguishable from the adult sample, and

as importantly, separate from the index mean (the 50/50 MNP death assemblage). There is

a real difference between the average shape (and therefore size) of snails recovered at the

site and what would be expected in a natural population. The snails from the site tend to be

larger, and are more likely to be adults. This strongly suggests that humans were directly

importing the snails to the site, and regardless of other expectations, were either selecting

for or presented with larger snails.

In summary, a method has been presented that allows determination of reasons for

the presence of Rabdotus in archaeological sites. The natural death assemblage of Rabotus

has been determined and found to consist of approximately 50% each adults and juveniles.

A model of this natural death assemblage (MNP) is drawn from the archaeological snails.

By dividing the width by the height of individual shells a comparative index figure is

derived that allows comparison of adult, juvenile, and the mean MNP width-to-height

ratios. This forms the comparative base against which the actual mean of the width-to-

height ratio from the site assemblage (ASP) is compared. This methodology is necessary

because of variation in absolute size based on species and/or environment. The statistically

valid sample representing all Rabdotus at the site (ASP) is compared with the index sample

(MNP). If the overall mean of the modeled population is equivalent to the site mean (as in

Figure 6) then the snails are most likely the result of natural processes. If it is significantly

different (as in Figure 8), and weighted towards larger specimens, it is very strong evidence

for the purposeful gathering of snails by human agents.

Other Considerations

It might be argued that simply looking at the percentages of juveniles would be

sufficient for differentiating between natural and artificial populations. Anything less than

50% could be considered the result of human gathering. A problem would result, of course,

in deciding at what point to make the break. This can be illustrated through analysis of the

experimental gathering of live snails conducted at the Brackenridge Field Laboratory

(BFL1). Of the 191 specimens not destroyed for other analyses, 68, or 35%, were

determined to be juveniles. This is well above the average site percentage of 10-20%, but

also much lower than the expected natural assemblage of 50%. Looking strictly at the

percentage of juveniles collected would be inconclusive; the ratio would have to be placed

subjectively somewhere within a continuum. By applying the methodology described

above, it was possible to put a finer point on the simulation. This is shown in Figure 9.

1911366868N =

Figure 9. Comparing an MNP (adult, juvenile, and 50% test) with the actual assemblage of

live snails from the BFL1 collection.

This shows that with 35% juveniles the total assemblage is still statistically distinct

from a natural population consisting of 50% juveniles. The live snails that were collected

cannot be distinguished from the adult population, again indicating that larger snails were

either selected for or were more readily available at the BFL.

It might also be asked if a 50% ratio of juveniles truly represents natural

populations. This can only be fully answered by repeated sampling from various areas and

environmental zones. It can be partially addressed, however, by examining the off-site

samples retrieved from shovel tests (the Off-Site ST collection). Out of 59 collected

(admittedly a relatively small sample), 32, or 54% were juveniles. This is exactly what was

predicted for natural populations by the collections at the BFL, and is accurate to ± 4.6 % at

the 95% confidence level (60 d.f.). The width/height relationships are presented in Figure

When Figure 10 is compared with Figure 6 it is clear that they are virtually identical

in distribution. The snails recovered from the site area, within the same landform, general

environment, and soils are comparable to the experimental BFL2 collection but not with the

assemblage from the site. A natural population consisting of approximately 50% juveniles

remains supported.

59542727N =

Figure 10. Comparing an MNP (adult, juvenile, and 50% test) with the actual assemblage

of shells from the Off-Site ST collection.

There is one more collection episode that requires discussion. An attempt was made

to quantify a natural death assemblage from the general vicinity of the site (Off-Site2).

This was achieved through the same methodology utilized at the BFL. The result was a

collection of 97 shells of which 35, or 36%, were juveniles, rather than the 50% juveniles

approximating a natural death assemblage as seen in the BFL2 collection.

Unlike at the BFL, where collection was within leaf litter under a closed tree

canopy, the off-site location collection was within an open upland grassland consisting of

dense bunch grasses within scattered secondary mesquite and juniper growth. Visibility

was severely hampered, and the nature of the grasses precluded effective coverage of the

actual ground surface. At the BFL the snails were collected within areas known to contain

living populations of snails, whereas at the second location, in spite of several

reconnaissance level surveys searching for live snails, none were ever witnessed. Rather

than a deciduous river terrace, the upland setting is either a stable or deflating surface, with

Late Archaic age artifacts (Pedernales points) seen on the surface. And finally, rather than

a generalized presence across the land form, despite extensive survey, only two widely

separated clusters of shell were observed.

The conclusions are that this last collection gathered snails that are the result of

many years of accumulation, and are perhaps subject to differential preservation and

certainly to differential visibility. When the methodology described above was applied the

total mean of all snails was similar to that of a natural population (Figure 11).

Compared to the 35% juveniles collected live (BFL1, Figure 9), the total mean of

this sample is closer to the expected 50% distribution than it is to the adult distribution, and

so is indicative of a natural population. The implications are that although this may be a

natural population consisting of 35% juveniles, the dynamics of that population are still

comparable to that of a population consisting of 50% juveniles. It appears that this sample

containing 35% juveniles is age-structured differently than the live BFL1 sample, (that also

contains 35% juveniles), suggesting that the methodology may hold for varying age-at-

death profiles and contains the ability to separate natural from gathered assemblages with

apparently equivalent death assemblages.

Looking closely at Figures 9 and 11, the differences are seen to be in the overall

width-to-height ratios. The live BFL1 collection resulted in an overall mean roughly

equivalent to the adult population. The Off-Site2 collection is statistically equivalent to its

MNP and is therefore a natural as opposed to gathered population. This is supportive of

relative size, rather than actual adult/juvenile ratios which are the determining factor in

differentiating between cultural and natural death assemblages.

97723636N =TotalMean50%testWidth/HeightJuvWidth/HeightAdult

Figure 11. Comparing an MNP (adult, juvenile, and 50% test) with the actual assemblage

of snail shells from the Off-Site2 collection.

More study can clearly be done, but for the present purposes, the 50% assumption

will be maintained and used as a base index from which the natural population is modeled.

This will allow a standardized methodology that can be applied to different sites with

varying snail assemblages in order to test for culturally introduced Rabdotus assemblages.

CHAPTER 7

RETURN RATES OF SNAILS

Once it has been shown that the snails from the archaeological site are the result of

human gathering activities, the middle range concepts of optimal foraging models can be

applied. Knowledge of the energetic value of the snails will enable placement in a rank

order list of potential food sources. Should snails have a high caloric return, they would be

expected to be a preferred food source, and gathered to the exclusion of other food items

with lower caloric values. If snails are low in calories, then it would appear that other

highly ranked food items have become scarce, and that foragers have broadened their diet

base to include lower ranked, and therefore lower return food items.

This assumes that calories are the currency. As was discussed earlier, there is

additional potential in understanding the role other nutrients may play in maintaining

human health. If, for example, bison was determined to be highly ranked as well as readily

available, it would be the expected food source, and all other food items would be passed

over until the return on bison dropped below that of the next ranked food. The result, of

course, would be some form of malnutrition based on a limited diet. Other food sources

would be required to maintain a minimal level of population health.

Reproductive fitness, the aspect of evolutionary ecology the currency is supposed to

measure, may not be limited to physical well-being. Social factors such as activities

promoting prestige may well contribute to an individual’s reproductive success. Such

influences cannot be placed on a quantitative scale.

The individual, however, can have no social success until some very basic energy

and nutritional needs are met. So following somewhat on Leslie White (e.g. 1959), social

factors can be factored out from discussions of primary causation, but perhaps reintroduced

when leaving the middle range to discuss more general or higher range theory. It follows,

then, that a basic understanding of the subject matter (here, the nutritional value of snails)

will aid in shaping larger questions that can be addressed through application of optimal

foraging models to the theory of evolutionary.

Methods

Ten patches exploited during two collecting episodes (WWF and BFL2) were

compared. The data considered included length in patch, time to new patch, size of patch,

total number collected, numbers of juveniles and adults, and weights of each. For the data

to be relevant and applicable to the site, it was necessary to adjust the weight figures.

Snails collected at the site tended to be substantially larger then those collected

experimentally. The reasons for this are unclear, but may pertain to species hybridization,

seasonality, age of snails, selective gathering by site inhabitants, or some combination of

the above.

One hundred snails from the site test column were chosen for determination of site

weights. The snails were selected from two levels that showed internal synchronicity in

quantities of snail, mussel shell, bone, burned rocks, and lithic debitage, as it was felt these

levels would be most likely to represent actual site activities. Snails were selected for

completeness and to a lesser extent, for size. This idealizes the data somewhat, but also

creates a site maximum against which other internal or external assemblages can be tested.

Meat weight was established by simply filling the shell with water, and then

determining the difference between the shell weight and the gross weight. Initial attempts

at weighing individual shells were impractical, as it was felt an excess of error was being

introduced through the fine level of control necessary to cleanly fill and weigh each shell.

The snails were therefore divided into groups of ten. The individual width and height of

each shell was recorded, the shells were weighed per batch of ten, and then filled with water

and reweighed, producing a net “meat” weight, which was averaged between batches, and

then between levels. The total mean weight was then divided by the sample n (100), to

obtain an average weight per individual. To obtain the average weight of juveniles, a single

batch of previously recorded sub-adults (n=45) was subjected to the same process.

Rather than using actual numbers of adults and juveniles collected experimentally,

the mean site ratio (12.5% juveniles) was applied to the total number gathered from each

patch. Thus, if 100 snails weighing 78 gm and consisting of 60 adults and 40 juveniles had

been experimentally collected, the data was adjusted to reflect site means, which in this

case, to use an actual example, would be 100 snails, of which 12.5 were juveniles weighing

7.5 gm (12.5 x .58gm), and 78.5 adults weighing 121.7 gm (78.5 x 1.55 gm), for a total

weight of 129.2 gm (the multipliers are explained below). This allowed meaningful

comparisons to be made between the various collecting episodes and determination of

return rates based on site, rather than purely experimental data.

The processing of snails requires removing them from their shells. This might be

accomplished through breaking the shell, but would result in an archaeological signature

very different from that observed. A limited series of processing experiments were

conducted on the collected live snails. Live snails were virtually impossible to remove, as

they clung tightly to the interior of their shells. Another problem encountered was the

amount of mucus secreted by the snails, whether alive or dead, which made them very

difficult to grasp. It was found that by placing the live snail in cold water, and then slowly

heating it to 120 degrees Farenheit (49 degrees Celsius), the snail was killed as it was trying

to remove itself from the heat source: ie, the body was extruding partially from the shell.

At this point, the snail could be readily removed by way of a knife tip piercing the main

body, and then prying the remainder of the animal from the shell. A number of snails were

frozen, and it was found that they were removed just as easily. It is not suggested that

snails were frozen prehistorically, but the process allowed additional experimental data to

be gathered without subjecting the snail to the heating process

A 200 gm sample of Rabdotus mooreanus snail meat from the BFL1 collection was

submitted to Analytical Food Laboratories located in Grand Prairie, Texas for analysis of

nutritional value. Approximately 1/4 of the total number were removed from the shell after

parboiling, and the rest were removed from previously frozen shells. An effort was made to

extract all the animal, including entrails, and to include as much of the mucus-like material

as possible. The laboratory ground and processed the sample as a single unit.

Results

Looking first at size, and then weight, the mean height of snail from the site was

25.80 mm, and the width was 13.91 mm, compared to 20.48 and 11.65 mm from the

experimental sample. The width-to-height ratio for the snails was .539 and .570

respectively, indicating the snails from the site were somewhat fatter. The average weight

of an adult from the site was determined to be 1.55 gm, while that of juveniles was .58 gm,

37% the weight of the adult. These figures were applied back to the experimental returns,

which were also adjusted to reflect the ratio of juveniles to adults as recovered from the

archaeological deposits.

A total of 177 minutes were spent in 6660 square m gathering 831 shells that would

have weighed 1187 gm if based on site averages. This results in an average of 4.69 snails

gathered per minute, and translates to 6.7 gm per minute and .18 gm per square m. More

importantly, this results in 14.9 minutes per 100 grams, or 400 gm collected per hour. The

time trial data combined with adjusted weights and juvenile/adult ratios are summarized in

Table 1.

It was found that meat removal averaged 10 per minute, and could conceivably

reach 20 per minute, based on a test in which dry, empty shells were subjected to the

motions of meat removal. This type of processing, if used, would increase handling time by

approximately 33 percent. The most likely way that snails (and mussels) would be

processed would be through boiling, a process most effective for processing animal tissues

low in lipids and with relatively high amounts of proteins (Wandsnider 1997: 12, Table 5).

If snails, mussels, bone fragments, and perhaps other food items were boiled, a type of stew

would result. A portion of the experimentally gathered live snails were boiled for a period

of time. The broth that resulted had thickened considerably, and was pungent with the not

wholly unobjectionable odor of snails. It would make little sense, at this point, to process

the snails further. Instead, it is much more likely that the diners consumed the various

elements separately and individually, sucking or pulling the snails from the shells and

scooping the mussel meat in a similar fashion. A modern paella dish can be envisioned.

Handling time is therefore included with consumption time, and as some or much of the

nutritive value would become contained in the broth, there seems to be little point in

pursuing additional handling times in respect to overall return rates.

Table 1. Comparing collection times, rates, and returns for ten patches.

Ptch# SqM TmIn(Min) TtlN #Juv GmJuv #Adlt GmAdlt TtlGm #/Msq #/Min Gm/Min GM/Msq

1 1600 12 26 3.25 1.885 22.75 35.2625 37.15 0.02 2.3 3.095625 0.023217

2 1250 9.67 54 6.75 3.915 47.25 73.2375 77.15 0.04 5.6 7.978542 0.061722

3 1250 35 152 19 11.02 133 206.15 217.2 0.12 4.3 6.204857 0.173736

4 60 4 13 1.625 0.9425 11.375 17.6313 18.57 0.22 3.25 4.643438 0.309563

5 400 15 45 5.625 3.2625 39.375 61.0313 64.29 0.11 3 4.28625 0.160734

Welder

1 200 15 65 8.125 4.7125 56.875 88.1563 92.87 0.325 4.3 6.19125 0.464344

2 160 24 198 24.75 14.355 173.25 268.538 282.9 1.24 8.25 11.78719 1.768078

3 900 30 25 3.125 1.8125 21.875 33.9063 35.72 0.03 0.8 1.190625 0.039688

4 600 21 155 19.38 11.238 135.63 210.219 221.5 0.26 7.3 10.54554 0.369094

5 240 11.5 98 12.25 7.105 85.75 132.913 140 0.41 8.5 12.17543 0.583406

6660 177.17 831 1187 4.69 6.701424 0.178272

With weights and collection times established, it is relevant to begin incorporating

the nutritional values of the snails, as provided through the laboratory analysis. Table 2

presents the raw data.

Table 2. Results of a nutritional analysis on 200 gm of Rabdotus mooreanus snail meat. Substance Units/100gm Ash 2.37%

Calcium 381mg

Calories 51.25

Carbs 3.98gm

Cholesterol 98.1mg

TotalFat .25gm

Iron 3.60mg

Moisture 85.13%

Niacin 1.60mg

Phosphorus .0611mg

Potassium 174mg

Protein 8.27gm

Riboflavin .632mg

Sodium 71mg

Thiamine .0573mg

Vitamin A 56 IU

These numbers are more meaningful when compared to other potential dietary

components such as other snails and freshwater mussel species. Analytical Food

Laboratories provided data on an unknown species of raw snail meat. There is some

information on the aquatic Jute snail, consumed by contemporary Maya (Healy et al 1990),

and commercial escargot values are readily available (e.g http://www.nal.usda/afsic

pubs/srb96-05.htm). A recent study by Lintz (1996) has produced data that indicates

mussels are more nutritious than indicated in the Parmalee and Klippel (1974) study.

Numerous references for other foods exist, and can be averaged for ease of reference.

These are summarized in Table 3.

Table 3. Comparing the nutritional value of Rabdotus mooreanus snails with other mollusks and generalized food types.

Rabdotus Snail1 Snail2 Snail3 Mussel4 Mussel5 Bird4 Meat4 Fish4 Plants5

Substance Units/100gm Ash 2.37 gm 3.65 3.2 1.3 1 1.15 Calcium 381 mg 170 10 345 845 43.45Calories 51.25 84 80.5 90 67.5 75 193 130.5 112 230 Carbs 3.98 gm 12 2 2 0 Cholesterol 98.1mg 50Fat-Soxhlet .25 gm 1.2 1 1.4 7.5 2.6 10.75 4.5 4.5Iron 3.60 mg 3.5 3.5 12.35 47.5 3.01Moisture 85.13% 79 79.2 79.35 81.8 65 73.5 77.5 Niacin 1.60 mg 1.4 1.45 .50 Phosphorus .0611 mg 272 666 Potassium 174 mg 382 33.5Protein 8.27 gm 6.3 16 16.1 8.65 12.2 22.55 21 17.45 6.06 Riboflavin .632 mg 0.12 0.25 .18 Sodium 71 mg 70 4.5 69Thiamine .0573 mg 0.01 0 .035Vitamin A 56 IU 100 72.5VitaminC 0 mg 26 4 Fiber 0 gm 1.15VitaminD VitaminE VitaminB6 0.13 mgFolacin VitaminB12 0.5 mcgMagnesium 250 mg 250 Zinc 1Iodine Folate 6 mcg Copper 0.4 mg

References 1. Healy et al. 1990 2. http://www.nal. usda/afsic pubs/ srb96-05.htm 3. Analytical Food Laboratories 4. Parmalee and Klippel 1974 5. Lintz 1996

These figures provide relative, per unit, values, rather than comparative return rates.

In general, animals have more potential return than plants, and plants are somewhat

comparable, in a general sense, to mollusks. More specific information is available

elsewhere for many plant and animal species (e.g. Sobolik 1991, Lintz 1996, Simms 1987).

It was shown that snails were collected at the rate of 400 gm/hour. This information

can now be translated into return times. The Recommended Daily Allowances for adult

males aged 23-50, as presented in Sobolik (1991) are used as a base comparison. This is a

close to maximum range in most of the nutritional elements, and again creates a threshold

against which idealized collection returns can be measured (Table 4). The table indicates

that the snail is a relatively efficient source of calcium, iron, and riboflavin, of which the

RDA of each could be acquired in less than one hour of gathering. Protein and potassium

are also readily available, while necessary carbohydrates could be acquired in half a day.

Sodium and thiamine are marginally available, but it is difficult to imagine a positive return

on calories after 13 hours of collecting. Caloric return is expressed in kcal per hour, and as

can be surmised from the data presented, snails return approximately 200 kcal/hr. The

reason for this low return may be based on the low fat content.

Table 4. RDA, time for acquisition, and percent per 100 gm meat for Rabdotus mooreanus. RDAMale23- Rab %100gmRab

Substance Units Units/100gm TimeForRDA Ash 2.37%Calcium 800 mg 381 .525 48Calories 2700 51.25 13 2Carbs 75 3.98 4.7 5Cholesterol 98.1 mgFat 20 gm .25 20 1.3Iron 10 mg 3.60 .69 36Moisture 85.13%Niacin 18 mg 1.60 2.8 9Phosphorus 800 mg .061g 3300 0Potassium 800 mg 174 1.15 22Protein 56 gm 8.27 1.7 15Riboflavin 1.6 mg .632 .63 40Sodium 2200 mg 71 7.75 3Thiamine 1.4 mg .0573 6.1 4Vitamin A 1000 UG 56 IU

Discussion

The number of snails from the two 5 cm levels selected for weight analysis were

1033 for one and 2065 for the other. This extrapolates to approximately 1500 and 3000 gm

respectively, and if multiplied by a minimum site area of 100 square m suggests that a fairly

substantial amount of time was spent gathering snails. If either of these levels can be

termed “floors,” then between 500 and 1000 hours may have been spent collecting.

Optimal foraging models can be constructed to try to determine why such effort was made

to acquire what seems as if it should be a low ranked resource. The most obvious

conclusion is that the resource base was widened, due to difficulty in obtaining higher

ranked resources. This may be a seasonal occurrence, or a long term period of resource

stress.

It was implied earlier that if snails were examined simply through gross caloric

value, they should be more highly ranked than rabbit but be less sought after than deer.

This would be based on an energy per unit evaluation. A number of resources from various

locations around the world have been evaluated through analysis of the post-encounter

return rate, which is the amount of energy acquired once the resource is encountered and

resultant processing costs are subtracted (Kelly 1995:78, Table 3-3). A few of these are

presented below for comparative purposes (Table 5), remembering that the return rate for

Rabdotus is 200 kcal/hour.

Table 5. Comparisons of energy return rates (kcal/hour) of various foods. From Kelly

(1995:Table 3-3) Resource Type Return Rate Deer 17,971 - 31,450Rabbit/Jackrabbit 8983 - 15,400Squirrel 2837 – 6341Lizard 4200 Duck 1975 – 2709Tuber 1724 Acorns 1488

Resource Type Return Rate Larvae 1486 Tansy mustard seed 1307 biscuitroot roots 1219 Sunflower seed 467-504 Wild rye seeds 266-473 Cattail roots 128-267 Squirreltail grass 91

Snails fall well within the lower ranked food items, with even resources having

extremely high processing costs (seeds) often returning more energy per unit of time than

the snails. Generally, it is lower ranked seeds, roots, and tubers that are most similar to

snails in caloric return. It would appear, that based on optimal foraging principles, these

lower ranked resources should not be included within preferred diets.

Although the return rate is based on post-encounter costs, the diet-breadth model

requires inclusion of encounter rates to explain foraging choices. This can be thought of as

numbers of encounters per unit of time as a large muli-variate patch (the total environment)

is being searched (Kelly 1995:83-84). If, for example, hypothetically following Kelly, one

unit of deer is encountered for every four units of rabbit, taking both deer and rabbit would

raise the return rate of taking either alone, as rabbit would be more plentiful, thus making

up for smaller body size. The most likely scenario would have rabbit hunting embedded in

deer acquisition strategies. If six lizards were also encountered and taken, however, the

return rate would begin to fall, as the time spent acquiring lizards would decrease from the

potential higher return afforded by the deer and rabbit. It follows then, that a forager should

not choose to pursue snails (or other low ranked resources) when encounter rates for more

highly ranked items remain frequent.

Perhaps the most important aspect of the diet-breadth model concerns the issue of

abundance. The assumption is that when highly ranked resources are available, lower

ranked resources will not be chosen, regardless of how abundant they are, and that only as

the higher ranked resources decrease in abundance (increasing search costs and therefore

lowering net return rates) will the diet breadth widen to incorporate lower ranked resources

(Kelly 1995:86-87). The implications for snail gathering are clear. Snails should not be

taken until any number of other resources have decreased in availability to the point where

gathering at a rate of 200 kcal/hour would not lower the average return rate.

The diet-breadth model further assumes that resources are distributed evenly, and

the chances of encountering any given resource are equivalent to its relative abundance

(Kelly 1995:90). Many resources are not evenly distributed, however, but are clumped

within patches. Foragers, then, would have the opportunity to make decisions as to what

resource patches they might wish to exploit, most likely as they make plans prior to leaving

camp (Kelly 1995:92). The patch-choice model is used to predict which patches a forager

should exploit, and much like diet-breadth, can result in rankings of patches (Kelly

1995:91). The model is commonly used to predict how long a forager should remain in a

patch (Kaplan and Hill 1992:178).

The basic premise is that a patch will be exploited until its return falls below what

could be expected from the mean return of all patches within the environment, once the

costs of traveling to any new patch is factored in (Kelly 1995:91). Each individual patch

should be depleted to a density that nets the same return rate, and as overall resources

become less abundant, the time spent within patches will increase (Kaplan and Hill

1992:180). An important implication is that no patch should be completely exhausted

(Kelly 1995:91), as that would indicate that the environment itself was no longer capable of

sustaining the forager, who by this point presumably should have left for more favorable

climes.

Snails are distributed patchily and have a return rate of 200 kcal/hour. In order for

snail patches to be considered as a source of subsistence, the patch-choice model indicates

that the mean return rate for all patches at the time of snail acquisition could not exceed 200

kcal/hour. This suggests a very poor or depleted subsistence base, either because of long-

term environmental degradation or seasonal stress.

Using either of these models follows on the essential premise of optimal foraging

theory that resides in the approximation of reality, rather than an assumption of absolute

validity. When human choice is factored in, for example, some models become

inappropriate and can produce results that are unrealistic (Kaplan and Hill 1992:180). A

basic premise of optimal foraging—randomness of searching strategies—introduces

additional layers of complexity (such as knowledge of environment, the role of foraging

groups as opposed to foraging individuals, and risk or predictability in resource acquisition

[Kelly 1995:101]) that are difficult to incorporate in simple models. Combining diet-

breadth and patch-choice models and including tools such as linear programming and

indifference curves may help, but the debate between simple and complex approaches (Sih

and Milton 1985, Hawkes and O’Connell 1985) seems to continue. Much of this revolves

around the issue of energy as currency.

At 41BL116 there seems to be close to 2000 years of heavy reliance on snails as a

food source. A straightforward optimal foraging approach would suggest that these low-

ranked animals should only be gathered when other items that achieved a higher energy

return were scarce. Although it cannot be presently demonstrated, it seems unlikely that a

riverine ecotonal environment should have such long-term and repetitive environmental

stress resulting in what would appear to be near starvation conditions. As present evidence

indicates that the climate during principal site occupation was relatively wet and mild

(Johnson 1995, Collins 1995), it would not be expected that energy acquisition would have

been especially problematic. A base assumption, then, might be that calories were being

provided at a rate much greater than that which can be obtained by snail gathering. It thus

becomes necessary to explore reasons other than caloric returns for the entry of snails into

an aboriginal diet.

Alternatives

It was shown that a diet heavy in hunted resources may result in deficiencies of

other important nutrients. An excess of protein consumption can be especially problematic

(discussed below). Alternative explanations for the presence of snails might therefore be

found in currencies other than energy. If resource rankings are expanded to other

nutritional elements items such as snails might be seen to rise in importance. It is

conceivable that sorted rankings might be established for various food types which could

then be compared on various levels, thus expanding the range of optimal foraging models

and perhaps allowing them to more accurately predict or explain variation in foraging

behavior.

It has already been suggested that there are strong relationships between mussels

and Rabdotus. They are both mollusks, are similarly structured within their respective

habitats, and have similar nutritional value. At 41BL116 their archaeological presence is

also strongly correlated in relation to each other (Figure 12).

Mussel

160140120100806040200-20

0 Rsq = 0.8725

Figure 12. Linear regression and best fit line comparing numbers of Rabdotus to numbers

of mussels per level.

Rabdotus is more strongly regressed against mussel, suggesting its presence is

somewhat more dependent on mussel than mussel is on Rabdotus. The differences are

fairly minor, however, but are much stronger than any other relationships, such as mollusks

and burned rock, lithics, or bone.

It is useful, then, to explore the nutritional commonalities between these two

animals, beginning with what they have in abundance, rather than what they are lacking.

Sobolik (1991) presents summary information on these substances, and her data is used

below. The figures following the various components indicate the acquisition time for

Rabdotus, based on the above Table 4.

Calcium (.525 hours [for RDA]) is found primarily in bones and is essential for

skeletal health. It also aids in the control of nerve and muscle impulses. A lack of calcium

can lead to osteoporosis and rickets. Riboflavin (.63 hours), is one of the B vitamins and

aids in defense against disease as well as contributes to general good health. Iron (.69

hours) is an essential trace element responsible for maintaining blood balance. Iron uptake

can be inhibited by excess calcium. Pregnant and nursing women require two to three times

the amount of iron than the of general population. Potassium (1.15 hours) is one of three

electrolytes and helps maintain cell structure. Niacin (2.8 hours), another B vitamin, aids in

metabolic processes, and a deficiency can lead to disorders associated with the skin and

mucus membranes. Carbohydrates (4.7 hours) provides energy in the form of starches,

sugars, and cellulose, and is considered the best form of obtaining such energy, normally

contributing over one-half total calories. Protein (1.7 hours) is another constituent of total

energy, but is very difficult to evaluate fully, as it consists of several amino acids, ten of

which are considered essential. These aid the body in maintaining cell health and replacing

those lost through normal attrition.

Snails (and mussels) are thus potentially valuable sources of calcium, iron,

riboflavin and niacin, containing more per unit of each of these than many plants and

animals (Sobolik 1991, Table 24, Table 26). Proteins and carbohydrates, however, are

easily found in greater quantities among several other plant and animal species, and

Rabdotus has a very low fat content. Mussels, it should be noted, have low carbohydrate

values. Those analyzed by Lintz (1996) contained no carbohydrates, while Parmalee and

Klippel (1974) had an average of about 6 gm/100gm. These three elements (protein, fats

and carbohydrates) make up the majority of total energy sources (Sobolik 1991:81).

Energy needs are variable depending on factors such as age, weight, activity level, and

gender. Fat is the most directly accessible component, either converted immediately to

energy or stored for future use, and has approximately 2.25 times the caloric value of

proteins and carbohydrates (Outram 2000:401).

Snails appear to provide adequate amounts of carbohydrates and protein, but are

seriously deficient in fats. A diet consisting primarily of snails might result in nutritional

stress based on a relative lack of dietary fat. Diets high in proteins can precipitate

additional health issues. Because of the difficulty in metabolizing proteins, liver and

kidney problems, potentially leading to death, may occur if energy intake exceeds over 50%

proteins daily, and potentially far less for pregnant women (Speth 1991:206). RDAs as

presented above indicate that protein intake should be approximately 75% of carbohydrate

intake. Snail contains 200% more protein than carbohydrates. One way to manage for a

protein excess may be to consume additional fats (which should be 25% of proteins) and

carbohydrates (Speth 1991:267), with the present case benefiting most from additional fats.

Mussels analyzed by Lintz (1996: Table 3) have an average fat component of 2.6

gm/100 gm meat, nearly ten times that of Rabdotus, but still quite low when compared to

various animal and some plant species. The nutritional value of mussels may be subject to

seasonal or environmental bias, especially in regards to carbohydrates and protein (Lintz

1996:T-9), but in general are relatively consistent (Parmalee and Klippel 1974, Claassen

1991: Table 10.1). Claassen reports Anbarra women gathering up to 800 kcal/hour of an

unspecified (marine?) mollusk (Claassen 1991:279). The only Western Pacific mollusk for

which she gives caloric data, Pecten maximus, provides 105 kcal/100gm (Claassen

1991:Table 10.1), thus indicating a gathering rate of over 800 gm per hour. The size of

these mussels is not stated, so it is unknown how many individuals that might translate to,

however, the species, also known as the King Scallop, is available commercially with stated

weights of 10-12 per pound (http://www.kildavanan.com/Products.htm) which converts to

approximately 45 gm per individual, or 18 individuals per hour. Lintz provides size data

for mussels in Texas of 23.8 gm per individual (Lintz 1996:T-9) and for the Midwest of 58

gm per individual (Parmalee et al. 1972 in Lintz 1996: T-9). If 18 Texas mussels were

collected in one hour, there would be a net return of 420 gm (.9 pounds), which would

provide 315 kcal/hour and almost 11 gm of fat, which is about one-half the RDA.

If these figures are correct, moderate amounts of mussel would compensate for the

low fat content of Rabdotus. Unfortunately, experimental gathering of mussel may never

be satisfactorily accomplished due to declining populations (Lintz 1996:T-14) and

diminishing habitat (Howells et al. 1996:1). A return rate of 300 kcal/ hour seems

reasonable, however, and even if it were decreased to 200 kcal/hour, which seems to be

close to a minimum (Simms 1987: Table 2, Table 5, Kelly 1995: Table 3-3) the requisite

amount of fat could be acquired in less than three hours. Eighteen mussels per hour also

compares very well with the collection rate of snails; both are gathered at the rate of just

over 400 gm/hour.

It was noted above that the two taxa for which Lintz provides data, Quadrula and

Cyrtonais, provide no measurable carbohydrates. This is curious when compared with

Parmalee and Klippel’s data for two different species in the Midwest, but is supported to

some extent by measured carbohydrates being absent in at least one marine mollusk, as well

as some birds and several fish (Claassen 1991: Table 10.1). The implication of course, is

that snails make up for the carbohydrates missing in the mussels. The two animals are

therefore complementary to each other; either one could supply several important minerals

and vitamins, but either by itself would result in deficiencies rooted in relative protein

excesses. Snails are shown to provide the adult male RDA of carbohydrates in 4.7 hours,

and it is suggested here that mussels can do the same for fats in 2 hours. If this balance is

achieved, a site assemblage might be expected to contain 36 mussels (72 shells) for every

1320 snail shells.

This assumption was tested with the site-derived regression formula where mussels

were independent of snail populations (r = .934, p = .001, y = -13.74x – 29.8). This was

both a stronger correlation, and intuitively more appropriate, than looking at mussels as

dependent on snails, as unmitigated protein consumption (if only snails were consumed) is

potentially more deleterious than a lack of carbohydrates (if only mussels were consumed).

When 72 shells (shells rather than “individuals” were used in the equation) were used to

solve for y, the result was 939 snails, leaving a residual of 381 from an idealized and

presumed ratio of snails and mussels (the ratio that produced RDA’s of carbohydrates and

fats, 72 mussel shell for every 1320 snails). This is close to the maximum residual of 338.

An actual site figure of 97 mussel shells was used in the same formula to predict the actual

number of snail shell. The predicted result was 1333, while the actual number recovered

was 1388, leaving an extremely small residual of 55. Seventy-two mussel shells represents

5.5% of 1320 snail shells. The actual site mean ratio of mussel shell to snail was

7.68±2.95%, which places the predicted ratio (5.5%) within the 66% margin of error. The

predicted ratio of mussel shells to snails that allows for RDA’s of carbohydrates and fats to

be minimally acquired (72:1320) is well supported, with a seeming slight de-emphasis on

snail collection, and therefore carbohydrates.

Mussels and snails, of course, did not comprise the totality of the diet. Bone is

present at the site, and although very fragmentary in nature, has been cursorily identified as

deer, rabbit, bird, and fish, but most often as medium-sized mammal. A pollen analysis

indicates that Asteracaea (sunflower), Liguliflorae (dandelion), Brassicacae (mustard),

Cheno-Am (goosefoot or pigweed), Platyopuntia prickly pear), Poacae (various grasses),

Vitis (grape), Carya, (hickory or pecan), Celtis (hackberry), Quercus (oak), Rhus (sumac),

and TCT (juniper or bald cypress) were present in the site vicinity. Many of these, in

particular the nut bearing species and the Cheno-ams have the potential for adding fat to the

diet. At present, though, there are no identified quantities for these plants, and so all must

remain as only potential additions to the diet.

Brown (1999:250) suggested looking for evidence of grease processing in sites

where Rabdotus consumption is suspected. Bone grease is the processed remains of both

marrow and the grease found within the bone itself, which can account for up to one-third

the total bone weight (Brink 1997:260). Processing requires breaking the bone into small

pieces and then boiling it for extended periods of time, eventually skimming the residual fat

off the surface of the water. It would seem to be a time consuming and laborious process,

with limited return potential.

Archaeological signatures from such processing include fragmented bone, often

termed “indeterminate” (Outram 2000) and differential preservation of bones containing

higher or lower amounts of available grease (Madrigal and Capaldo 1998). Bone grease

processing appears to be more prevalent during times of resource stress, and is seen world-

wide (Outram 2000: 401). A paucity of complete longbones coupled with higher numbers

of grease-poor bones, in particular phalanges, would be indicators of such activities

(Madrigal and Capaldo 1998). Efficient grease processing requires storage until a sufficient

amount can be processed, which is difficult to accomplish in warm climates due to

problems with preservation, and may be mitigated by less intensive procedures such as

making bone broth or adding bone to stews (Outram 2000:402).

At site 41BL116 there is so far a very poor correlation between bone and other

artifact classes, including snail and mussel. Although general trends in quantities are

observed, there seems to be no direct connection between them. If site inhabitants were

depending on bone to provide the fats necessary to offset the high protein levels of snails,

there should be a more obvious correlation. So although the bone is generally in a very

fragmentary state, and the majority of easily identifiable or whole bones are phalanges, it

would seem that grease processing, if it occurred, was not intrinsically linked to molluscan

consumption. One explanation, based on the level of energy input represented by the

mollusks, is that hunting activities were actually a minor aspect of activities at this site,

because of resource stress and a widened breadth of diet, and that when vertebrate animals

were acquired, they were processed completely.

An alternative, of course, might lie in the other nutritional components. Mollusks

are relatively high in calcium, iron, potassium, and two of the B vitamins. It has already

been demonstrated that these nutrients could be acquired in only a few hours of collecting.

In effect, a return rate for these nutrients has been established. By comparing nutritional

return rates with other potential food sources macronutrients can also be ranked. They can

then be compared individually and as groups. This was accomplished for five food sources:

deer, rabbit, acorns, mussel, and snail (Table 6).

Table 6. Comparing the nutritional and caloric returns for five potential food sources.

Nutritional Content/100gmResource kcal/100g kcal/hr gm/hour Fat Protein Carb Ca Fe K Ribo NiacinDeer 130 20,000 15,000 4 20 0 10 2.5 382 0.48 6.3Rabbit 70 10,000 14,000 5 20 0 20 1.5 360 0.19 9Acorn 400 1500 375 10 5 40 45 1.3 175Mussel 60 300 500 2.5 12 0 800 48 33 0.18 0.5Snail 50 200 400 0.25 8 4 380 3.6 174 0.63 1.6

Nutritional Grams/HourDeer 600 3000 0 1500 375 57,000 72 945Rabbit 700 2800 0 2800 210 50,000 27 1260Acorn 37.5 18.75 150 170 5 650Mussel 12.5 60 0 4000 240 165 1 2.5Snail 1 32 16 1520 14 700 2.5 6.4

Recommended Daily AllowancesRDA kcal

2700 20 56 75 800 10 800 1.6 18Percent RDA/Hour

Deer 740 3000 5350 0 188 3750 7000 4500 5200Rabbit 370 3500 5000 0 350 2100 6200 1700 7000Acorn 55 187 33 200 21 50 80Mussel 11 62 107 0 500 190 20 63 15Snail 7 5 57 21 190 140 88 156 35

Sources: Lintz 1996, Claassen 1991, Sobolik 1991.

The first section provides the calories per unit, the return rate in calories per hour,

and the number of grams per hour necessary to achieve the caloric return. Next, the

nutritional content for eight components is presented. The following section shows how

many grams per hour are potentially available from the different food sources. The RDA is

provided again for reference, and finally, the percent of the RDA for each nutritional

component that can be acquired in one hour is shown. Both nutritional grams per hour and

percent RDA per hour can be used as indexes of return. As can be seen, both deer and

rabbit provide very high amounts of all the listed items except carbohydrates.

Unless deer and rabbit populations were extremely depressed, most of the

nutritional needs in question could be easily met without a widened diet breadth. Based on

this limited comparison, it is the carbohydrates that must be used to explain the molluscan

presence. Carbohydrates contribute starches and sugars towards energy needs, and as was

stated earlier, can provide over one-half of total calories. Neither fish, birds, or mammals

contribute carbohydrates to the diet; they are found only in plants (Sobolik 1991:Table 23)

and certain mollusks, including Rabdotus snails.

A basic biology textbook (Cambell 1993:809-811) expands on the role of

carbohydrates in the mammalian diet. Adenosine triphosphate (ATP) is the molecule that

allows cells to do work, and is generated from the oxidation of carbohydrates, fats, and

proteins. Fats oxidize at twice the value (kcal) of carbohydrates and proteins (1 gram of fat

provides 9.5 kcal). Fats and carbohydrates are the preferred energy source; proteins do not

metabolize except under extreme stress (starvation). Excess fats and carbohydrates are both

stored as fats in body tissues (carbohydrates are converted), to be held in reserve until

needed. If these stores are exhausted, the body’s proteins are broken down, and muscle and

even brain tissue is affected. To avoid permanent damage, calories (in the form of fats or

carbohydrates) are necessary to stave off cell depletion.

The actual numbers ,therefore, of deer or rabbit need not necessarily have been

reduced, only their fat content. This again points to environmental stress. By incorporating

mollusks in the diet, dependence on fat-bearing foods was lessened. The most likely

scenario involves periodic (seasonal) times of reduced primary production. Late

winter/early spring and late summer/early fall are the most likely times for this, when plants

are leaving dormancy (late winter) or have either expended or not yet realized reproductive

tissue potential (late summer). Secondary production (foraging herbivores) would begin to

lose stored energy resources, and perhaps initiate protein metabolization. The cascade

reaches the omnivores, such as humans, who must then diversify (broaden the diet breadth)

to maintain cell (and body) health. An abundant, predictable, low risk resource would be

particularly important at such times.

It is now possible to make predictions about the abundance and relative health of

highly ranked resources, such as deer. Deer have been shown to return 600 grams of fat per

hour. This is presumed to be from healthy and viable populations. Snails return 16 grams

of carbohydrates per hour, the equivalent caloric potential of 8 grams of fat. For snails to

efficiently replace the caloric potential of deer, the abundance and/or fat content of deer

would need to be substantially reduced. If meat weight return remained constant, the fat

return would drop to .0005 grams/hour. If the potential fat return of deer was at the

minimal value of 8 grams/hour, the meat return would be 200 grams/hour or less.

These are extremely low figures. Deer would essentially be non-existent or

undergoing starvation. The more likely explanation is that deer (and rabbit) were not

present within the foraging environment at times when mollusks were taken. The

implication is of a broad resource patch that has been depleted, but not exhausted. The

mean return rate of the total foraging environment would be at 200 cal/hour, or perhaps at 8

grams of fat (16 grams of carbohydrates)/hour. Such returns would still outweigh the costs

of moving to a new patch (foraging environment), especially if there was a regional

depression of a broad spectrum of resources. Again, this is most likely a seasonal

development. Exploitation of mussels might be most feasible during late summer, and

might attract human populations to mussel patches. As fall rains begin, snail returns would

rise in importance as availability increased. Fall seed crops would begin to reach fruition,

and as mast increased, the health and abundance of herbivores would increase as well.

Over-wintering may have occurred, but foragers may well have left for other patches if the

overall return rate began to increase again.

Somewhat different conclusions were presented by Klippel and Morey (1986), who

recovered hundreds of thousands of small-bodied aquatic snails at an Archaic site in

Tennessee. After establishing cultural introduction to the site they evaluated the nutritional

content (similar to Rabdotus) and compared it to deer. Their data, however, showed deer as

completely lacking in important vitamins and minerals such as the B vitamins, iron, and

potassium (compare with Table 6, above). Their conclusion was that the snails were an

important complementary portion of the diet, and procured during late summer when water

levels were manageable and, in Tennessee, other resources such as deer were healthy and

readily available. The snails provided nutritional needs difficult to obtain through other

means. Although the majority of the macronutrient information must be revised, a similar

argument can be made here for carbohydrates. Rather than higher ranked animals being

absent, a relative lack of other carbohydrate sources may have precipitated molluscan

gathering in addition to the continued acquisition of large and medium sized mammals.

By looking at nutritional returns as well as caloric values, it is possible to further

test and refine expectations presented by the optimal foraging model. The interpretations

presented above are highly speculative, but not unreasonable. Although energy returns

showed that mollusks should be low ranked, understanding the nutritional role of

carbohydrates potentially helps to explain a seeming importance as a food source. It is

possible that there are other reasons or complicating factors that might also contribute to the

presence of these animals. The next chapter will begin by testing other aspects of the

patch-choice model, and then conclude by revisiting the global model presented earlier.

This will be an attempt to link the middle range methodology to higher levels of model

building suggested by evolutionary ecology. The results may be tentative and perhaps even

untestable, but as above, may also be reasonable explanations for the seeming

incongruencies presented by the subsistence data.

CHAPTER 8

CONCLUSIONS

A Limited Test Of Optimal Foraging Concepts

Patch Choice, Time in Patch, and Search and Pursuit Times. Optimal foraging

models make presumptions based on net energy returns; when costs of acquisition are

outweighed by the energy return, a positive balance is achieved, and the rational forager

would theoretically pursue this successful strategy. Once the return no longer exceeded the

effort expended in acquisition, the forager would then make decisions, conscious or not, as

to how to best regain a positive return. This includes choice of prey, choice of gathering

locale (patch), breadth of diet, commitment of time, group size, and location of settlement

(Bettinger 1987:131). In some cases, optimization based on combinations of these various

factors may not be possible; environmental or social factors may be limiting. If this is not a

temporary situation, the forager will suffer, physically or socially, with the end result being

a loss of reproductive potential.

Actualistic studies designed to test such models can be inconclusive. Modern

gatherers making broad assumptions about gathering and processing techniques can

produce data that is useful, but perhaps questionable (e.g. Simms 1984, Smith et al. 2000),

and at times contradictory (Kornfeld 1994, Broughton 1995, cited in Smith et al. 2000).

Regardless, following on middle range theory (Binford 1981, Bettinger 1987), such efforts

help in developing a corpus of data that can be used comparatively by testing new studies

against it.

The present project looks at snails as a potential food source. It began by

establishing that snail populations within an archaeological site showed a significantly

different population structure than populations found in natural (non-site) settings. It was

also necessary to determine the return rate of snails, thus allowing their ranked placement

within possible diet choices. From this it may be possible to reach certain conclusions as to

general local conditions during site occupation. This is something of a coarse-grained

application. Although very specific data are being applied, they are being used in order to

ascertain a fairly broad level of interpretation.

Collection procedures also allow a more fine-grained application, here, specifically

related to search and pursuit times, and how they relate to patch choice. The normal

currency for such studies is energy, often expressed as calories (Kelly 1995:101, 102). As

intimated above, however, collecting episodes can result in highly conjectural and

unverifiable data; the modern archaeologist who gathers grass seeds, grasshoppers, or snails

is not subject to the same environmental and cultural factors of the prehistoric forager. It

must be reiterated, however, that such studies are necessary and are indeed a vital means of

establishing baseline data from which increasingly refined models can be derived and

tested.

Returning to the issue of currency and scale of application, there are two distinct

collecting episodes that can be used to test aspects of optimal foraging models. One

consisted of the collection of live snails, for ultimate nutritional analysis, and the other

consisted of the collection of dead snails (shells) as a proxy for live snails when it was

determined that no live snails were forthcoming at the collection site. This data can be used

not only for return rates, when either real or hypothesized nutritional value is determined,

but also to test for time spent within and between patches, and to explore the reasoning

processes that led to such choices.

The Collections. Two of the collections, the WWF and BFL1, were used to test for

time in patch, a component of the patch-choice model. The relevant data was time spent

collecting, area collected, the number collected, and the collecting density, i.e., the

encountered/collected number of snails per area unit rather than the actual number of snails

within the patch. As already stated, although travel times were recorded during the BFL1

episode, they were felt to be unrepresentative of prehistoric foraging, based largely on the

sample size and imprecise knowledge of the environment, and so were not included in

calculations, although they are presented in summary Table 7. These data allowed some

basic conclusions to be drawn in regards to relative energy expenditures.

The methodology can be evaluated in both subjective and objective terms.

Subjectively, as snail collection episodes progressed, it was felt that there was a

concomitant increase in knowledge, particularly at the BFL. Once a landform or

environmental setting produced positive results, similar settings became targeted. This is

most obvious in the high return per minute and low travel times seen at BFL patches 2 and

3. It was also noted that when collecting, there was a tendency to collect almost all

available specimens, regardless of size, once a particular collection had begun. The actual

process was surprisingly strenuous, and involved repeated stooping, at times requiring

reaching into thorny underbrush, which introduced a certain risk factor. By establishing a

lowered position it seemed desirable to maximize the return before returning to an upright

posture. Snail densities have been reported elsewhere as reaching up to 18 individual per

square m. Although not empirically quantified, it was noted that snails in the larger patches

were commonly seen in small groups, typically around 4-5, and commonly as many as ten

or so within a poorly defined space that might average 1-2 square m. These would be seen

within the larger patches, with the result being that a single patch would contain numerous

subpatches which could be individually targeted. It was at these times that maximization

was most fully indicated. The main patch would be either transected (as at the WWF) or

randomly walked (as at the BFL), until it was felt that all subpatches had been exploited.

The narrow transects of the WWF collection undoubtedly produced a greater level of

control, and as Table 7 shows, a greater recovery (by a factor of 4) then the random walks

at the BFL. The BFL data, however, most likely represent a greater level of reality.

Results. At the WWF 2100 square m produced 541 shell in 101.5 minutes, and at

the BFL 4200 square m produced 247 live snails in 61.34 minutes, for a total of 788 snails

collected from 6300 square m in 162.84 minutes (2.7 hours), averaging 4.8 snails per

minute and .125 snails per square m. The four patches for which search time is included

had returns of 221 snails pursued for 49.34 minutes for 4.5 snails per minute. When search

times were added (19.42 minutes) the return rates fell to 3.2 snails per minute,

approximately 80% of the total average return rate, and 70% of the return rate for the four

patches. Individual patch return times ranged from .8 to 8.5 snails per minute.

Table 7. Gross rates of return for ten patches collected for Rabdotus species snails. Site Patch # TimeToNew SqM TimeIn #Cllctd #/Min #/MSq

WWF 1 nd 200 15 65 4.3 .325

2 nd 160 24 198 8.25 1.24

3 nd 900 30 25 .8 .03

4 nd 600 21 155 7.3 .26

5 nd 240 11.5 98 8.5 .41

Total/

Average

2100 101.5 541 5.3 .25

BFL 1 na 1600 12 26 2.2 .02

2 2.25 1250 9.67 54 5.58 .04

3 2.5 1250 35 152 4.34 .12

4 14 60 4 13 3.25 .22

5 .67 40 .67 2 2.98 .05

Total/

Average

4200 61.34 247 4 .06

GrTotal/

Average

6300 162.84 788 4.8 .125

Discussion. It is somewhat difficult to compare the collections from the WWF and

the BFL. Not only are they from different environmental regions, but the snails at the

WWF were shell, while those at the BFL were living. The argument that the WWF

collection is valid requires the acknowledgment that although the observed and collected

shells most probably represent a palimpsest of both recent and more distant deaths, the

community structure remains essentially the same as a living population, and has merely

become more concentrated over time. This is supported by the patchy and subpatchy

natural distribution of the shells, which largely mimicked distributions at the BFL as seen in

both the living and dead populations.

Viewed objectively, the data present several interesting implications. The analytical

focus was on time spent in patch, and it was hoped that patterns would emerge that could

suggest at what intensity a patch might be exploited, and for what length of time. The time

in patch was thus a dependent variable, and utilizing linear regression techniques, was

compared against patch size, total number collected, number collected per minute, and the

observed density, or number per square m, based on number collected. Also examined was

whether the rate of collection and total number collected was dependent on the density, and

whether patch size affected total collection, rate of collection, or relative density of

populations. Although scatter plots indicated trends that were visually appealing, best-fit

lines and related statistics were not always supportive of the pre-assumed relationships. It

is likely that the small sample size and increasing levels of experience in recognizing snail

habitats contributed to the statistical discrepancies. It is also possible to examine individual

cases and discern reasons for non-fit of data.

The most obvious relationship, and one of the most significant, was the association

between the density of snails (x) and the rate of collection (y). As the density (observed

and collected number per m squared) increased, so did the rate of recovery (r = .670, y =

4.81x + 3.46, p=.034). The same can be said of the total number collected (r = .697, y =

130.81 + 43.412, p = .025) (Figure 13). When snails were more visibly concentrated, they

were collected at a faster rate with a larger number finally collected.

NumberCollected

3002001000-100

0 Rsq = 0.3834

Figure 13. Linear regression and best fit line comparing time spent in each patch and the

number of snails collected.

The total number of snails collected within any patch size (y) was virtually a straight

line relationship, with results statistically insignificant (r = .036, y = - .00424x + 81.471, p

= .922), i.e., the number of snails collected did not appear to be dependent on patch size.

Slightly more significant was an indication that the rate of collection (y) actually decreased

as patch size increased (r = .324, y = .00147x + 5.687, p = .361), an observation supported

to some extent by indications that densities (y) also decreased as patch size increased (r =

.481, y = -.0003x + .462, p = .16), remembering, however, that densities are a function of

collection, and not the actual number of snails in any one patch. This supports the inference

of subpatchy distribution, with intra-patch concentrations maintaining localized availability.

Overall patch size does not seem to be of critical importance when determining return rates.

When examining the actual time spent within individual patches (size), the strongest

associations were with the total number of snails collected (y) (r = .619, y = .0997 + 8.424,

p = .056). As time in the patch increased, so did the total number collected. This was not

unexpected. It was surprising though, to see that there were no strong relationships

between time spent in the patch and size of patch (Figure 14), the densities within the patch

(Figure 15), and the collection rate (Figure 16), although visual but statistically unsupported

trends were seen.

SizeMSq

180016001400120010008006004002000

number of snails collected.

Number/MSq

1.41.21.0.8.6.4.20.0

number of snails collected per square m (density).

Number/Minute

1086420

Figure 16. Linear regression and best fit line comparing the time spent in each patch and

the number of snails collected.

Increasing patch size (x) showed a general trend towards resulting increase in length

of search time (Figure 14) but was statistically insignificant (r = .38, y = .00727x + 11.704,

p = .278), as was the density (Figure 15) (r = .199, y = 6.019x + 14.656, p = .581), and

return rate (Figure 16) (r = .044, y = .187x + 15.395, p = .903) when measured against time

spent in the patch. Restated, search times were somewhat longer in larger patches (per

unit), denser patches, and patches providing a higher rate of return.

Taken as a whole, the data seem to suggest that gathering success is determined

primarily by rate of return. Because rate of return and prey density remained fairly

constant, the resource would seem to be predictable within the environment. The foraging

strategy is obviously one of energy maximizing, rather than time minimizing, with no

obvious advantage taken from attempts to exploit patches of different sizes or even

densities. The energy return rate remains fairly consistent.

The experimental gathering episodes, when viewed subjectively, may help clarify

potential strategies. While gathering, if snails seemed to be abundant, that is, visible, they

were gathered regardless of perceived return rates or overall density; if the collection

container was filling consistently, collection continued. At the same time, there were

perceptions that at some point returns were diminishing, and a new patch was exploited.

Efforts to determine when that might happen are so far statistically inconclusive, but using

Figure 16 as an approximation, patch abandonment was initiated when the return rate fell

below two snails per minute. What remains to be seen is if this makes nutritional sense.

A two snail per minute return based on the approximate average weight of 1.5 gm

per adult snail would result in a collection rate of 180gm/hr (95 kcal/hour), roughly half

(45%) the average rate of return of 404 gm/hr (200 kcal/hour). Acquisition times for the

RDA of nutritional elements would therefore double, with protein requiring 3.5 hours and

carbohydrates 9.5 hours to satisfy the recommended allowances. Patch number 3 at the

WWF (see Table 7) was the only one in which the number per minute fell below two. A

bias based on the literature review suggesting snails were abundant within prickly pear

patches resulted in an inordinate amount of time being spent in this patch, and it obviously

should have been abandoned long before it was, with return rates of 72 grams, or 37

kCal/hr. The rate of two snails per minute is therefore presented as a postulated minimal

return, below which a new patch would be searched for and subsequently collected.

Should this interpretation hold, it would indicate, based on the patch-choice model,

that the actual mean return rate of all patches in the environment, rather than being 200

kcal/hour, would actually be closer to 100 kcal/hour. As an exploited patch would of

necessity be less productive after collection, the total environment would be required to be

less productive than the 200 kcal/hour that would allow snails to be introduced in the first

place. This seems unlikely, and requires additional research before it can be stated as fact.

Snails may be more productive than suggested here, or, other reasons for snail-based

subsistence my need to be explored.

Testing The Global Model

A model based on global parameters was presented above. Based on assumptions of

broad ecological determinants and observed variability of human groups within a variety of

settings, predictions were made for what might be expected for Central Texas in terms of

what can broadly be termed settlement patterning. The snail data presented allow some of

these predictions to be more fully tested. These include models of population size,

seasonality and mobility, and social organization.

Population Size. An exercise often attempted involves the determination of human

population sizes based on the amount of food available for consumption. Normative figures

for band sizes have been postulated as ranging from between 25 and 500 individuals, with

bands of 25 perhaps being more common for nomadic groups, and much larger numbers

being observed for sedentary groups (Kelly 1995:209-211). Collins (1973), examined the

number of mussel shells found within a burned rock midden at the Devil’s Hollow site in

Travis County, Texas. By looking strictly at the number of individual mussels

(approximately 1200) and making arbitrary estimates for daily consumption rates, he

derived a range of periods in which the mussels, and hence the midden deposits, might

accumulate (Collins 1973:94-97).

Lintz, using similar reasoning, was able to show that discrete mussel features at

41TG307 and 41TG309 could have supplied the minimal daily requirements for between

one to nine individuals (Lintz 1996:T-14). Parmalee and Klippel, meanwhile, estimated

that a group of 25 persons would require around 2000 mussels per day to meet caloric

requirements, thus arguing that mussels of necessity would be a dietary supplement rather

than a mainstay (Parmalee and Klippel 1974:431, 433). Erlandson (1988) cites these

figures but then argues that the same group could achieve its protein needs (note the mixed

currencies) with only 300 mussels per day (Erlandson 1988:105-106), a figure comparable

to Lintz’s, whose data can be manipulated to show that about 390 Texas mussel would

supply adequate protein to a group of 25 persons (Lintz 1996:Table4).

If a minimum use area of 100 square m is assumed, some 300,000 grams, or almost

210,000 snails may have been collected during a single occupation sequence. This would

supply a group of 25 adult males necessary protein for 17 days, carbohydrates for 6.5 days,

and calories for 3. Using the regression formula presented earlier (36 mussels for every

1320 snails), approximately 5700 mussels (130,000 gm) would be expected within the same

level. The same 25 persons (adult males) would have the necessary protein for 11 days, fat

for 6.5 days, and calories for 1.5. Combined, protein is sufficient for close to a month,

carbohydrates and fats for one week, while calories are seriously deficient.

Although 300,000 grams seems a tremendous amount, it can be shown

(theoretically, based on Table 1) that one person could collect 3200 grams in an eight hour

day. It would therefore take this single person 93 days to collect 300,000 gm. It follows

that 10 persons could collect the same amount in nine days, and if all 25 persons were

collecting, approximately 3.7 days, which would come close to meeting the carbohydrate

and caloric needs, respectively, for the group of 25. If mussels are included, with collection

at the rate of 4000 gm/person/day, then 10 persons could provide a 6.5 day fat supply for 25

adult males in approximately 4 days. As long as labor and supply is sufficient, a positive

energy and basic nutritional balance would be maintained.

Seasonality and Mobility. Snails are most easily gathered beginning in late spring

through perhaps early to mid fall. During cold weather months they would be unavailable.

During the heat of the summer some species may be highly visible while estivating above

ground, but the experimental gathering exercises described here suggest that snails will be

most visible during rainy periods, which are most likely to occur during late spring and

early fall, in particular, May and September (Carr 1967:Figure 4).

Mussels, although having irregular reproductive strategies across species, as a group

tend to spawn in late spring through early fall (Howells et al. 1996:9), during which their

body mass may increase by as much as 30% (Lintz 1996:T-4). Gathering mussels,

meanwhile, would be easier (less labor intensive) during periods of low water (Claassen

1991:290) which can be assumed to be during late summer, especially for shallow water

species (Lintz 1996:T-4).

If mollusks are the main subsistence base, and were utilized for up to five months,

then indications are that prehistoric populations moved from this location to others on a

seasonal basis. Supporting a relatively high level of mobility (or at least a lowered level of

sedentarism) is the lithic assemblage, which consists of unequal proportions of formal to

informal tools. Out of 259 tools so far recovered, 159, or 61% are considered formal tools,

while the remaining 100, or 39%, are considered informal. Formal tools are defined as

bifaces, whether or not complete, projectile points, and well-made scrapers. The informal

tools are primarily flakes with evidence of edge modification, either through intentional

retouch or through use. This relatively low proportion of “situational gear” as compared to

“personal gear” (Binford 1979) can be used as a means of understanding mobility patterns

(Sulliven and Rozen 1985:74). A toolkit with low diversity indicates relatively high

mobility while more mobile groups might also be expected to carry a relatively large

number of flake tools sized from 1.5 to 3 times the minimum useable size (Kuhn 1994:435).

Bifaces are “maintainable” in a field situation, and so are to be expected within mobile task

groups or populations, while on-site activities allow for expediently manufactured flakes

(Bamforth 1991:229-230).

Tethered collectors, on the other hand, would tend to repeatedly occupy sites with a

resultant increase in artifact diversity, particularly at base camps (Binford 1980). While as

yet there are no in depth studies of the lithic debris from 41BL116, the high number of

formal tools coupled with a lack of immediately accessible chert resource areas suggests

that the site may have served as a retooling station, during which blanks or preforms,

prepared elsewhere, were reduced further while residents subsisted on the readily available

mollusks. Many of the bifaces and projectile points are broken, and, especially among the

Darl and Ensor assemblage, many are complete (unbroken) but appear exhausted. Cores

are also extremely rare, as are large cortical flakes. Reduction of blanks during retooling

would have produced the types of flakes sufficient for expedient cutting, sawing, and

scraping purposes.

Site 41BL116 is suggestive of people “mapping on” to a resource (mollusks) and

then moving the population to the resource, rather than sending out logistically based

parties as might be expected of collectors operating within Binford’s (1980)

collector/forager spectrum. A predictable and stable resource allowed a period of at least a

few weeks for refurbishing of the formal hunting assemblage prior to the group’s assumed

movement to areas more favorable for hunting endeavors.

Social Organization. Shellfish, and by extension, mollusks, are often described as a

low-ranked and generally undesirable food source (Claassen 1991: 278-279, Erlandson

1988:107, Bird and Bliege Bird 2000:471). As a gathered (as opposed to hunted) resource,

the task of acquisition most likely fell primarily on women (Glassow and Wilcoxen

1988:47, Erlandson 1988:107, Claassen 1991), and children (Bird and Bliege Bird 2000,

Hawkes et al. 1995) and as such should allow at least tenuous interpretations as to gendered

space and division of labor. Men are not necessarily excluded from such activities, but in

general men are described as hunters (Hawkes et al. 1991, Gero1991:167) or fishers

(Claassen 1991:286-287) even though if the entire range of what constitutes “hunting” is

considered, the role of women becomes much more significant (Brumbach and Jarvenpa

1997) or even central (Estioko-Griffin and Griffin 1981).

The role of children cannot be overlooked. The behavior of children when

gathering may differ significantly from that of adults, with the archaeological signature

likewise changing. As an example, it has been shown that Meriam children exploit a

greater variety of shellfish than their adult counterparts, and are less likely to “field

process” them with resultant midden deposits therefore skewed towards children’s

activities, which may inflate the on-site abundance of such resources (Bird and Bliege Bird

2000:473).

Gathered resources, meanwhile, are often consumed, either partially or wholly,

while gathering is in progress (Hawkes et al. 1995:690, Woodburn 1968:51) which would

result in that portion of activity to be lost to the archaeological record (Bird and Bliege Bird

2000:468) and so make population size and nutritional analyses largely irrelevant (Claassen

1991:286). The assumption is that immediate hunger is satisfied while gathering, with any

excess being returned to camp for communal consumption.

The sheer volume of mollusks at 41BL116 precludes differential presence due to

children’s activities, nor is it likely that greater quantities were consumed off-site. Rather,

the acquisition of these animals was an important and integral portion of the seasonal

subsistence patterns of local people. Ethnographic evidence suggests that women, and to

some extent, children, were the primary “breadwinners” at these times. It may have been a

period during which men conducted technological maintenance and renewal of inter (and

perhaps intra) band social ties at a time in which they were freed, to some extent, from the

more mundane aspects of day-to-day subsistence needs. Women were not necessarily

relegated to supporting roles through allowing men the opportunities to pursue these other

activities. It is entirely possible that this activity actually was recognized as a valuable

contribution with women achieving praise and status as a result of their efforts (Claassen

1991:285).

Conclusions. Consumption of mollusks at 41BL116 may have been an integral part

of site formation. The amounts present allow group size to be postulated, and the

population dynamics of the resource provide information from which periods of occupation

and lengths of stay can be suggested. Ethnographic comparisons are a means of gaining

insight into how labor was divided, and the role of men, women, and children within the

local social structure. The global model suggested that group size would be between 20 and

60 persons, they would be moderately to highly mobile, and women would provide the bulk

of the food. These assumptions all fall within the realm of possibilities as allowed by the

molluscan data, with the most likely discrepancy being a potential lower level of mobility

than that suggested by the model. The model also suggested little to no reliance on aquatic

resources. While this may have been true in other settings, at 41BL116, aquatic resources

appear to be intrinsically linked to settlement and subsistence strategies, with the collection

and consumption of Rabdotus species snails an important component of those strategies.

Summary

The issue of human consumption of Rabdotus species snail has been variously

assumed or denied, based primarily on the investigator’s experience and professional

biases. This study does not settle the issue, but it does provide multiple lines of evidence

that strongly support the intentional gathering and consumption of snails at 41BL116. It

has presented a method that can be replicated by others, and, for the first time, has

quantified important nutritional components of Rabdotus species snails.

Snail populations were found to be differently structured when found within an

archaeological site assemblages as opposed to a natural environment. The differences were

statistically significant, and therefore quantifiable. The result is a step by step methodology

that allows a site assemblage to be compared to a natural population. If they are similar,

human gathering is not supported; if they are different, humans most likely were purposely

acquiring the snails.

Optimal foraging theory is one means of trying to understand why snails might have

been gathered. The basic premise of diet-breadth and prey choice, coupled with new

empirical information on the nutritional value of snails indicates that they would not have

been the prey of choice when other food items were plentiful. The implications are that

there were most likely seasonal and repetitive periods when higher ranked preferred

resources became less abundant, and the acquisition of snails thus became a reasonable and

rational means of acquiring necessary energy.

Understanding this small portion of the foraging decision process provides an

opportunity to examine in greater detail other aspects of settlement and subsistence.

Models based on other aspects and interpretations of archaeological materials can be

compared and tested one against the other and, in reciprocal fashion, can become restated

and increasingly refined.

It is recognized that there are shortcomings with the approach. Most obviously, it

cannot be “proven” that humans consumed snails until diagnostic portions of the snail body

are recovered from human coprolites. This may never occur.

There may be other reasons than selective gathering for the observed difference

between on-site and off-site snail population structures. These might include differential

preservation of older, thicker shelled adults, or might involve a return to the commensal

scavenger theory, with more adults than juveniles making their way to human occupation

areas. As yet untested and perhaps unconceived differences in microenvironments,

including some aspect of anthrosols, may result in similar distributions.

Although these and other complaints may be voiced against the findings presented

here, the rule of Occam’s Razor perhaps provides the strongest level of support. Given the

wealth of data, the most parsimonious explanation, by far, is that humans were consuming

snails.

A wealth of additional work can still be supported with the data. The initial

questions of when, how and why can be further refined and addressed by collection of more

fine-grained information. The apparent long-term, repetitious use of the site for

functionally similar purposes has implications for a greater understanding of larger issues of

regional land use (Smith and McNees 1999). Studying human subsistence strategies in

greater detail can clearly help in exploring these larger issues. Studying human

consumption of mollusks adds detail, and thus clarity, to the data from which conclusions

are derived.

REFERENCES CITED

Allen, D. C. and E. P Cheatum 1960 Ecological Implications of Fresh-Water and Land Gastropods in Texas Archeological Studies. Bulletin of the Texas Archeological Society 31:291- 316. Bailey, R. C. 1991 The Behavioral Ecology of Efe Pygmy Men in the Ituri Forest, Zaire. Anthropological Papers No. 86. Museum of Anthropology, University of Michigan. Bamforth, D. B 1991 Technological Organization and Hunter-Gatherer Land Use: A California Example. American Antiquity 56(2):216-235. Belovsky, G. E. 1988 An Optimal Foraging-Based Model of Hunter-Gatherer Population Dynamics. Journal of Anthropological Archaeology 7:329-372. Bettinger, R. L. 1987 Archaeological Approaches to Hunter-Gatherers. Annual Review of Anthropology 16:121-142. Binford, L. R. 1972 An Archaeological Perspective. Seminar Press, New York. 1972a Archaeology as Anthropology. In An Archaeological Perspective, by Lewis R. Binford. Seminar Press, New York. 1979 Organization and Formation Processes: Looking at Curated Technologies. Journal of Anthropological Research 35(3)255-273. 1980 Willow Smoke and Dog’s Tails: Hunter Gatherer Settlement Systems and Archaeological Site Formation. American Antiquity 45(1):4-20.

1981 Bones: Ancient Men and Modern Myths. Academic Press, New York. 1982 The Archaeology of Place. Journal of Anthropological Archaeology 1:5-31. 1990 Mobility, Housing and Environment: A Comparative Study. Journal of Anthropological Research 46:119-152. Bird, D. W. and R. B. Bird 2000 The Ethnoarchaeology of Juvenile Foragers: Shellfishing Strategies among Meriam Children. Journal of Anthropological Archaeology 19:461-476. Blair, W. F. 1950 The Biotic Provinces of Texas. Texas Journal of Science 1(1):93-117. Boas, F. 1940 Race, Language and Culture. MacMillan Company, New York. Boone, J. L. and E. A. Smith 1998 Is it Evolution Yet? A Critique of Evolutionary Archaeology. Current Anthropology 39(Supplement):S141-S173. Brink, J. W. 1997 Fat Content in Leg Bones of Bison bison, and Applications to Archaeology. Journal of Archaeological Science 24:259-274. Broughton, J. M. 1995 Resource Depletion and Intensification During the Late Holocene, San Francisco Bay: Evidence from the Emeryville Shellmound Vertebrate Fauna. Ph.D. Dissertation, University of Washington, Ann Arbor. UMI Dissertation Services. Broughton, J. M. and J. F. O’Connell 1999 On Evolutionary Ecology, Selectionist Archaeology, and Behavioral Archaeology. American Antiquity 64(1):153-165.

Brown, F. ca. 1900 Annals of Travis County and the City of Austin from the Earliest Times to the Close of 1875. Manuscript on file, Austin History Center, Austin. Brown, K. M. 1999 Snails From the Quarter-Inch and Eighth-Inch Screens. Appendix F (pp. 213-275) In The Smith Creek Bridge Site (41DW270) A Terrace Site in DeWitt County, Texas, by Dale Hudler, Keith Prilliman, and Thomas Gustavson. Texas Archeological Research Laboratory, Studies in Archeology 35 and Texas Department of Transportation Environmental Affairs Division, Archeology Studies Program, Report 17, Austin. Brown, T., K.L. Killen, H. Simons, and V. Wulfkuhle 1982 Resource Protection Planning Process for Texas. Texas Historical Commission, Austin. Brumbach, H. J., and R. Jarvenpa 1997 Ethnoarchaeology of Subsistence Space and Gender: A Subarctic Dene Case. American Antiquity 62(3):414-436. Butler, W. B. 1987 Significance and Other Frustrations in the CRM Process. American Antiquity 52(4) 820-829. Cambell, N. A. 1993 Biology, Third Edition. Benjamin Cummings, New York. Carr, J.T. 1967 The Climate and Physiography of Texas. Report No. 53. Texas Water Development Board, Austin. Chang, C. 1992 Archaeological Landscapes: The Ethnoarchaeology of Pastoral Land Use in the Grevena Province of Northern Greece. In Space, Time, and Archaeological Landscapes, edited by J. Rossignol and L Wandsnider, pp. 257-282. Plenum Press, New York.

Cheatum, E. P. and R. W. Fullington 1971a The Aquatic and Land Mollusca of Texas. Part One: The Recent and Pleistocene Members of the Gastropod Family Polygyridae in Texas. Bulletin 1, Dallas Museum of Natural History, Dallas. 1971b The Aquatic and Land Mollusca of Texas: Supplement: Keys to the Families of the Recent Land and Fresh-Water Snails of Texas. Bulletin 1, Dallas Museum of Natural History, Dallas. 1973 The Aquatic and Land Mollusca of Texas. Part Two: The Recent and Pleistocene Members of the Puplidae and Urocoptidae (Gastropoda) in Texas. Bulletin 1, Dallas Museum of Natural History, Dallas. Claassen, C. P. 1991 Gender, Shellfishing, and the Shell Mound Archaic. In Engendering Archaeology: Women and Prehistory, edited by J. M. Gero and M. W. Conkey, pp. 276-300. Blackwell, Oxford. Clark, J. W. Jr. 1969 Implications of Land and Fresh-Water Gastropods in Archaeological Sites. Arkansas Academy of Science Proceedings 23:38-52. 1973 The Problem of the Land Snail Genus Rabdotus in Texas Archeological Sites. The Nautilus 87(1):24. 1976 Alvar Nunez and the Snail Rabdotus in Texas. The Nautilus 90(1):13-14. Collins, M. B. 1972 The Devil’s Hollow Site, A Stratified Archaic Campsite in Central Texas. Bulletin of the Texas Archeological Society 43:78-100. 1995 Forty Years of Archeology in Central Texas. Bulletin of the Texas Archeological Society 66:361-400.

2001 Archeology of the Lampasas Cut Plain from Paleoindians to Pioneers: 2001 TAS Field School – Archeological Survey, Testing, and Excavation. Texas Archeology: The Newsletter of the Texas Archeological Society 45(1): 3-6. Collins, M. B., C. B. Bousman and T. K. Perttula 1993 Quaternary Environments and Archeology in Northeast Texas. In Archeology in the Eastern Planning Region, Texas: A Planning Document, edited by N. A. Kenmotsu and T. K. Perttula, pp. 46-67. Cultural Resource Management Report 3. Department of Antiquities Protection, Texas Historical Commission, Austin. Cronk, L. 1991 Human Behavioral Ecology. Annual Review of Anthropology 20:25-53. Dennet, D. 1998 Comments. Current Anthropology. 39(Supplement):S157-S158. Drennan, R. D. 1996 Statistics for Archaeologists: A Common Sense Approach. Plenum Press, New York. Dunnell R. C. and W. S. Dancey 1983 The Siteless Survey: A Regional Scale Data Collection Strategy. In Advances in Archaeological Method and Theory, Vol. 5, edited by Michael B. Schiffer, pp. 267-287. Academic Press, New York. Dwyer, P. D. 1985 A Hunt in New Guinea: Some Difficulties for Optimal Foraging Theory. Man, New Series 20(2)243-253. Ebert, J. I. 1992 Distributional Archaeology. University of New Mexico Press, Albuquerque. Ellis, G. L., and G. A. Goodfriend 1994 Chronometric and Site-Formation Studies Using Land Snail Shell: Preliminary Results. In Archeological Investigations on 571 Prehistoric Sites at Fort Hood, Bell and Coryell Counties, Texas, edited by W. Nicholas

Trierweiler, pp. 183-201. Resource Management Series Research Report No. 31. United States Army Fort Hood Archeological Resource Management Series. Mariah Associates, Austin. Ellis, G. L., G. A. Goodfriend, J. T. Abbott, P. E. Hare, and D. W. Von Endt 1996 Assessment of Integrity and Geochronology of Archaeological Sites Using Amino Acid Racemization in Land Snail Shells: Examples from Central Texas. Geoarchaeology: An International Journal 11(3):189-213. Ellis, L. W. 1997 Hot Rock Technology. In Hot Rock Cooking the Greater Edwards Plateau: Four Burned Rock Midden Sites in West Central Texas, Volume 1. by S. L. Black, L. W. Ellis, D. G. Creel, and G. T. Goode, pp. 43-81. Studies in Archeology 22. Texas Archeological Research Laboratory, The University of Texas at Austin, and Report 2. Texas Department of Transportation and Environmental Affairs Department, Archeology Studies Program, Austin. Ellis, L.W., G. L. Ellis, and C. D. Frederick 1995 Implications of Environmental Diversity in the Central Texas Archeological Region. Bulletin of the Texas Archeological Society 66:401-426. Erlandson, J. M. 1988 The Role of Shellfish in Prehistoric Economies: A Protein Perspective. American Antiquity 53(1)102-109. Estioko-Griffin, A. and P. B. Griffin 1981 Woman the Hunter: The Agta. In Woman the Gatherer, edited by F. Dahlberg, pp. 121-151. Yale University Press, New Haven. Foley, R. 1985 Optimality Theory in Archaeology. Man, New Series 20(2)222-242. Fullington, R. W., and W. L. Pratt 1974 The Aquatic and Land Mollusca of Texas Part Three: The Helicinidae, Carychiidae, Achatinidae, Bradybaenidae, Bulimidae, Cionellidae, Haplotrematidae, Helicidae, Oreohelicidae, Spiraxidae, Streptaxidae,

Strobilopsidae, Thysanophoridae,,Valloniidae (Gastropoda) in Texas. Bulletin 1. Dallas Museum of Natural History, Dallas. Gatschet, A. S. 1891 The Karankawa Indians, The Coast People of Texas. Archaeological and Ethnological Papers of the Peabody Museum 1(2). Harvard University, Cambridge. Gaynor, F. 1959 Concise Dictionary of Science. Philosophical Library, New York. Gero, J. M. 1991 Genderlithics: Women’s Roles in Stone Tool Production. In Engendering Archaeology, edited by J. M. Gero and M. W Conkey, pp. 163-193. Blackwell, Oxford, UK. Glassow, M. A. and L. R. Wilcoxon 1988 Coastal Adaptations Near Point Conception, California, with Particular Regard to Shellfish Exploitation. American Antiquity 53(1):36-51. Goodfriend, G. A. 1989 Variation in Land-Snail Shell Form and Size and Its Causes: A Review. Systematic Zoology 35(2):204-223. 1992 The Use of Land Snail Shells in Paleoenvironmental Reconstruction. Quaternary Science Reviews. 11:665-685. Hall, G. D. 1981 Allens Creek: A Study in the Cultural Prehistory of the Lower Brazos River Valley, Texas. Research Report 61. Texas Archeological Survey, The University of Texas at Austin. 1998 Prehistoric Food Resource Patches on the Texas Coastal Plain. Bulletin of the Texas Archeological Society 69:1-10.

Harris, M. 1968 The Rise of Anthropological Theory. Thomas Y. Crowell, New York. Hastorf, C. A. 1991 Gender, Space and Food in Prehistory. In Engendering Archaeology, edited by J. M. Gero and M. W Conkey, pp. 132-159. Blackwell, Oxford, UK. Hawkes, K. and J. F. O’Connell 1985 Optimal Foraging Models and the Case of the !Kung. American Anthropologist 87:401-405. Hawkes, K., J. F. O’Conell, and N. G. Blurton Jones 1991 Hunting Income Patterns among the Hadza: Big Game, Common Goods, Foraging Goals and the Evolution of the Human Diet. Philosophical Transactions of the Royal Society of London, Series B 334:243-251. 1995 Hadza Children’s Foraging: Juvenile Dependency, Social Arrangements, and Mobility among Hunter-Gatherers. Current Anthropology 36(4):688- 700. Headland, T. N. and J. D. Headland 1997 Limitation of Human Rights, Land Exclusion and Tribal Extinction: The Agta Negritos of the Philippines. Human Organization 56:1:79-89. Healy, P. F., K. Emery, and L. E. Wright 1990 Ancient and Modern Maya Exploitation of the Jute Snail (Pachychilus). Latin American Antiquity 1(2):170-183. Henry, D. O. 1995 Cultural and Paleoenvironmental Successions Revealed by the Hog Creek Archeological Investigations, Central Texas. In Advances in Texas Archeology: Contributions From Cultural Resource Management, Volume 1, edited by J. E. Bruseth and T. K. Perttula, pp. 51-79. Cultural Resource Management Report 5. Texas Historical Commission, Department of Antiquities Protection, Austin.

Hester, T. R., and T. C Hill, Jr. 1975 Eating Land Snails in Prehistoric Southern Texas: Ethnohistoric and Experimental Data. The Nautilus 89(2):37-78. Hill, K. 1988 Macronutrient Modifications of Optimal Foraging Theory: An Approach Using Indifference Curves Applied to Some Modern Foragers. Human Ecology 16(2)157-197. Honea, K. H. 1962 The Rammadyat of Northwest Africa and the Burned Rock Middens of Texas. Bulletin of the Texas Archeological Society 32:316-320. Howells, R. G, R. W. Neck, and H. D. Murray 1996 Freshwater Mussels of Texas. Texas Parks and Wildlife Department, Inland Fisheries Division. Texas Parks and Wildlife Press, Austin. Hubricht, L. 1960 The Genus Bulimulus in Southern Texas. The Nautilus 74(2)68-70. 1985 The Distributions of the Native Land Mollusks of the Eastern United States. Fieldiana: New Series 24. Publication 1359. Field Museum of Natural History, Chicago. Huckabee, Jr, J. W., D. R. Thompson, J. C. Wyrick, and E. G. Pavlat 1977 Soil Survey of Bell County, Texas. United State Department of Agriculture. Jarman, M. R., C. Vita-Finzi, and E. S. Higgs 1972 Site Catchment and Analysis in Archaeology. In Man, Settlement and Urbanism, edited by P. J. Ucko, R. Tringham, and G. W. Dimbleby, pp. 61- 66. Duckworth. Jelks, E. B. 1962 The Kyle Site: A Stratified Central Texas Aspect Site in Hill County, Texas. Archeology Series 5. Department of Anthropology, The University of Texas at Austin.

Jochim, M. 1983 Optimization Models in Context. In Archaeological Hammers and Theories, edited by J. A. Moore and A. S. Keene, pp. 157-172. Academic Press, New York. Johnson, L. 1964 The Devils Mouth Site: A Stratified Campsite at Amistad Reservoir, Val Verde County, Texas. Archeology Series 6. Department of Anthropology, The University of Texas at Austin. 1989 Great Plains Interlopers in the Eastern Woodlands during Late Paleoindian Times: The Evidence from Oklahoma, Texas, and Areas Close By. Report 36. Office of the State Archeologist, Texas Historical Commission, Austin. 1991 Early Archaic Life at the Sleeper Archeological Site, 41BC65 of the Texas Hill Country, Blanco County, Texas. Report No. 39. Publications in Archaeology, Texas State Department of Highways and Public Transportation, Highway Design Division, Austin. 1994 The Life and Times of Toyah-Culture Folk: The Buckhollow Encampment, Site 41KM16, Kimble County, Texas. Report 38. Office of the State Archeologist, Texas Historical Commission, Austin. 1995 Past Cultures and Climates at Jonas Terrace, 41ME29, Medina County, Texas. Report No. 40. Office of the State Archeologist, Texas Department of Transportation and Texas Historical Commission, Austin. 1997 The Lion Creek Site (41BT105), Aboriginal Houses and Other Remains at a Prehistoric Rancheria in the Texas Hill Country (Burnet County). Report 1. Environmental Affairs Division, Archeology Studies Program, Texas Department Transportation, Austin, and Report 41. Office of the State Archeologist, Texas Historical Commission, Austin. 2000 Life and Death as Seen at the Bessie Kruze Site (41WM13) on the Blackland Prairie of Williamson County, Texas. Report 22. Archeology Studies Program, Environmental Affairs Division, Texas Department of Transportation, Austin.

Johnson, L. Jr. D. A. Suhm, and C. D. Tunnell 1962 Salvage Archeology of Canyon Reservoir: The Wunderlich, Footbridge, and Oblate Sites. Bulletin No. 5. Texas Memorial Museum, The University of Texas at Austin. Johnson, L. and G.T. Goode 1994 A New Try at Dating and Characterizing Holocene Climates, as Well as Archeological Periods, on the Edwards Plateau. Bulletin of the Texas Archeological Society 65:1-51. Kaplan, H., and K. Hill 1992 The Evolutionary Ecology of Food Acquisition. In Evolutionary Ecology and Human Behavior, edited by E. A. Smith and B. Winterhalder, pp. 167- 202. Aldine de Gruyter, New York. Keeley, L. H. 1988 Hunter-Gatherer Economic Complexity and “Population Pressure”: A Cross-Cultural Analysis. Journal of Anthropological Archaeology 7:373- 411. Keene, A. S. 1979 Economic Optimization and the Study of Hunter-Gatherer Subsistence Settlement Systems. In Transformations: Mathematical Approaches to Culture Change, edited by C. Renfrew and K. Cooke, pp. 367-404. Academic Press, London. 1983 Biology, Behavior, and Borrowing: A Critical Examination of Optimal Foraging Theory in Archaeology. In Archaeological Hammers and Theories, edited by J. A. Moore and A. S. Keene pp. 137-155. Academic Press, New York. Kelley, J. C. 1947 The Lehmann Rock Shelter: A Stratified Site of the Toyah, Uvalde, and Round Rock Foci. Bulletin of the Texas Archeological Society 18:115-128. Kelly, R. L. 1995 The Foraging Spectrum: Diversity in Hunter-Gatherer Lifeways. Smithsonian Institution Press. Washington.

Klein, R. G. and K. Cruz-Uribe 1984 The Analysis of Animal Bones from Archeological Sites. The University of Chicago Press, Chicago. Klipperl, W. E. and D. F. Morey 1986 Contextual and Nutritional Analysis of Freshwater Gastropods from Middle Archaic Deposits at the Hayes Site, Middle Tennessee. American Antiquity 51(4): 799-813. Kornfeld, M. 1994 Pull of the Hills: Affluent Foragers of the Western Black Hills. Ph.D. Dissertation. University of Massachusetts. An Arbor. UMI Dissertation Services. Krebs, C. J. 1994 Ecology: The Experimental Analysis of Distribution and Abundance. Harper Collins College Publishers. New York. Krebs, J. R. and N. Davies 1978 Behavioral Ecology: An Evolutionary Approach. Blackwell, Oxford. Kuhn, S. L 1994 A Formal Approach to the Design and Assembly of Mobile Toolkits. American Antiquity. 59(3)426-442. Kuhn, T. S. 1996 The Structure of Scientific Revolutions, Third Edition. University of Chicago Press, Chicago. Kuznar, L. A. 1997 Reclaiming a Scientific Anthropology. AltaMira Press, Walnut Creek, Ca. Lanata, J. L. 1998 Comments. Current Anthropology 39(5)636-637.

Lintz, C. 1996 Dietary Data of the Mussel Shell Assemblage. In Early Archaic

Use of the Concho River Terraces: Cultural Resource Investigations at 41TG307 and 41TG309, Tom Green County, San Angelo, Texas, by J. M. Quigg, J. Peck, C. Lintz, A, C. Treece, C. D. Frederick, R. Clem, G. L. Ellis, P. Schuchert, and J. T. Abbot, pp. T-1-T-19. Technical Report No. 11058. TRC Mariah Associates, Austin.

Lintz, C. and J. T. Abbot 1997 Chronometric Dating of Snail Shells and Charcoal as an Assessment of Sediment Integrity at Archeological Sites 41ZP39 and 41ZP176, Porcion 18 Tract, Near Falcon Reservoir, Zapata County, Texas. Project No. 21116. TRC Mariah and Associates Inc, Austin. Leach, E. 1970 Claude Levi-Strauss. Viking Press, New York. Lee, R. B. and I. DeVore 1968 Problems of the Study of Hunters and Gatherers. In Man the Hunter, edited by R. E. Lee and I. DeVore, pp. 3-12. Aldine Atherton, Chicago. Lyman, R. L. and M. J. O’Brien 1998 The Goals of Evolutionary Archeology. Current Anthropology 39(5)615- 651. Madrigal, T. C. and S. D. Capaldo 1999 White-Tailed Deer Marrow Yields and Late Archaic Hunter-Gatherers. Journal of Archaeological Science 26:241-249. Martin, J. F. 1983 Optimal Foraging Theory: A Review of Some Models and Their Applications. American Anthropologist 85:612-629. McGlade, J. 1995 Archaeology and the Ecodynamics of Human Modified Landscapes. Antiquity 69:113-132.

McMahon, C. A., R. G. Frye, and K. L. Brown 1984 The Vegetation Types of Texas Including Cropland. Texas Parks and Wildlife, Austin. Meffe, G. K. and C. R. Carroll 1994 Principles of Conservation Biology. Sinauer, Sunderland, Ms. Montesquieu 1900 [1748] The Spirit of Laws. Translated by Thomas Nugent. Colonial Press, New York. Moore, J. A. 1981 The Effects of Information Networks in Hunter-Gatherer Societies. In Hunter Gatherer Foraging Strategies, edited by B. Winterhalder and E. A Smith, pp. 194-217. University of Chicago Press. 1983 The Trouble with Know-It-Alls: Information as a Social and Ecological Resource. In Archaeological Hammers and Theories, edited by J. A. Moore and A. S. Keene, pp. 173-191. Academic Press, New York. Moore, J. D. 1997 Visions of Culture. Altamira Press, Walnut Creek. Morgan, L. H. 1982 [1877] Ancient Society. Tai Offset Press, Calcutta. Murdock, G. P. 1967 Ethnographic Atlas. University of Pittsburgh Press, Pittsburg. Naveh, Z. and A. S. Lieberman 1983 Landscape Ecology: Theory and Application. Springer-Verlag, New York. Neck, R 1994 Interpretation of Molluscan Remains from the Mustang Branch Site (41HY209). In Archaic and Late Prehistoric Human Ecology in the Middle Onion Creek Valley, Hays County, Texas, by R. A. Ricklis and M. B.

Collins, pp. 491-497. Studies in Archeology 19. Texas Archeological Research Laboratory, The University of Texas at Austin. 1997 Appendix: Environmental Assessment of the Immediate Vicinity of the Lion Creek Site (41BT105). In The Lion Creek Site (41BT105), Aboriginal Houses and Other Remains at a Prehistoric Rancheria in the Texas Hill Country (Burnet County), by Leroy Johnson, pp. 193-186. Report 1. Environmental Affairs Division, Archeology Studies Program, Texas Department of Transportation, Austin, and Report 41. Office of the State Archeologist, Texas Historical Commission, Austin. Netting, R. M. 1986 Cultural Ecology, Second Edition. Waveland Press. Prospect Heights, Illinois. Nordt, L. C. 1992 Archaeological Geology of the Fort Hood Military Reservation, Ft, Hood, Texas. Research Report No. 25. United States Army Fort Hood Archaeological Resource Management Series, College Station. O’Brien, M. J. 1996 Evolutionary Archaeology: An Introduction. In Evolutionary Archaeology: Theory and Application, edited by M. J. Obrien. pp. 1-15. University of Utah Press. O’Brien, M. J , and T. D. Holland 1995 The Nature and Premise of a Selection-Based Archaeology. In

Evolutionary Archaeology Methodological Issues, edited by P. A. Teltser, pp. 175-200. The University of Arizona Press, Tucson.

O’Dea, K. 1991 Traditional Diet and Food Preferences of Australian Aboriginal Hunter- Gatherers. Philosophical Transactions of the Royal Society of London B. 334:233-241.

Orton, R. B. 1969 The Climate of Texas. In Climates of the States Volume 2-Western States, by Officials of the National Oceanic and Atmospheric Administration, pp 827- 920. United States Department of Commerce. Outram, A. K 2001 A New Approach to Identifying Bone Marrow and Grease Exploitation: Why the “Indeterminate” Fragments should not be Ignored. Journal of Archaeological Science 28 :401-410. Owen, J. G. and D. J. Schmidly 1986 Environmental Variables of Biological Importance in Texas. Texas Journal of Science 38(2):99-119. Pallotino, M. 1991 A History of Earliest Italy. Translated by M. Ryle and K. Soper. University of Michigan Press, Ann Arbor. Parmalee, P. W. and W.E. Klippel 1974 Freshwater Mussels as A Prehistoric Food Resource. American Antiquity 39(3)421-434. Patterson, L. W. 1995 The Archeology of Southeast Texas. Bulletin of the Texas Archeological Society 66:239-264. Pearl, F. B. 1997 Geoarchaeological Investigations of the Upper Lampasas River, Texas. unpublished Master’s Thesis. Texas A&M University, College Station, Texas. Prewitt, E. R. 1981 Cultural Chronology in Central Texas. Bulletin of the Texas Archeological Society 52:65-90. 1985 From Circleville to Toyah: Comments on Central Texas Chronology. Bulletin of the Texas Archeological Society 54:201-238.

1991 Burned Rock Middens: A Summary of Previous Investigations and Interpretation. In The Burned Rock Middens of Texas, An Archeological Symposium, edited by T. R. Hester, pp. 25-32. Studies in Archeology 13. Texas Archeological Research Laboratory, The University of Texas at Austin. Purchon R. D. 1977 The Biology of the Mollusca, Second Edition, Pergamon Press, Oxford. Rafferty, J. E.

1985 The Archaeological Record on Sedentariness: Recognition, Development, and Implications. In Advances in Archaeological Method and Theory, Vol. 8, edited by M. Schiffer, pp. 113-156. Academic Press, New York.

Randolph, P. A. 1973 Influence of Environmental Variability on Land Snail Population Properties. Ecology 54(4):933-955. Rappaport, R. A. 1967 Pigs for the Ancestors. Yale University Press, New Haven. Reidhead, V. A. 1980 The Economics of Subsistence Change: Test of an Optimization Model. In Modeling of Prehistoric Subsistence Economics, edited by T. Earle and A. Christenson, pp. 141-186. Academic Press, New York. Root, D. 1983 Information Exchange and the Spatial Configuration of Egalitarian Societies. In Archaeological Hammers and Theories, edited by J. A. Moore and A. S. Kane, pp. 193-219. Academic Press, New York. Rosenzweig, M. L. 1968 Net Primary Productivity of Terrestrial Communities: Predictions from Climatological Data. The American Naturalist 102(923) 67-75.

Rousseau, Jean-Jacques 1998 [1775] A Discourse on the Origin of Inequality. In The Social Contract and Discourses. Translated by G. D. H. Cole, pp. 31-126. Everyman, London. Sahlins, M. 1968 Notes on the Original Affluent Society. In Man the Hunter, edited by R. B. Lee and I. DeVore, pp. 85-89. Chicago, Aldine. Schiffer, M. B. 1999 Behavioral Archaeology: Some Clarifications. American Antiquity 64(1)166-168. Shafer, H. S. 1963 Test Excavations at the Youngsport Site: A Stratified Terrace Site in Bell County, Texas. Bulletin of the Texas Archeological Society 34:57-81. Sih, A. and K. A. Milton 1985 Optimal Diet Theory: Should the !Kung Eat Mongongos? American Anthropologist. 87:396-401. Simmons, F. 1956 Snails of the Burnt Rock Middens. In Central Texas Archeologist No. 7,

edited by Frank Watt, pp. 48-51. Central Texas Archeologist, Waco, Texas.

Simms, S. R. 1987 Behavioral Ecology and Hunter-Gatherer Foraging: An Example for the Great Basin. BAR International Series 381. Smith, E. A. 1979 Human Adaptation and Energetic Efficiency. Human Ecology 7(1):53-74. 1998 Comments. Current Anthropology. 39(5)640-641.

Smith, C. S. and L. M. McNees 1999 Facilities and Hunter-Gatherer Long-Term Land Use Patterns: An Example from Southwest Wyoming. American Antiquity 64(1):117-136. Smith, E. A. and B. Winterhalder 1981 New Perspectives on Hunter-Gatherer Socioecology. In Hunter Gatherer Foraging Strategies, edited by B. Winterhalder and E. A. Smith, pp. 1-12. University of Chicago Press. Smith, E. A. and B. Winterhalder 1992 Natural Selection and Decision-Making: Some Fundamental Principles. In Evolutionary Ecology and Human Behavior, edited by E. A. Smith and B. Winterhalder, pp. 25-60. Aldine de Gruyter, New York. Sobolik, Kristen D. 1991 Prehistoric Diet and Subsistence in the Lower Pecos as Reflected in Coprolites from Baker Cave, Val Verde County, Texas. Studies in Archeology 7. Texas Archeological Research Laboratory. The University of Texas at Austin. Speth, J. D. 1991a Foreword. In The Behavioral Ecology of Efe Pygmy Men in the Ituri Forest, Zaire, by Robert C. Bailey, p. ix-xii. Anthropological Papers No. 86. Museum of Anthropology, University of Michigan,. 1991b Protein Selection and Avoidance Strategies of Contemporary and Ancestral Foragers: Unresolved Issues. Philosophical Transactions of the Royal Society of London Series B 334:265-270. Steward, J. H 1972 [1955] Theory of Culture Change: The Methodology of Multilinear Evolution. University of Illinois Press, Urbana. Suhm, D. A. 1960 A Review of Central Texas Archeology. Bulletin of the Texas Archeological Society 29:63-107.

Sullivan, A. P. and K. C. Rozen 1985 Debitage Analysis and Archaeological Interpretation. American Antiquity 50(4) 755-779. Tacitus 1942 [AD 98] Germany and Its Tribes. In The Complete Works of Tacitus. Translated by Alfred J. Church and W. J. Brodribb, pp. 709-732. The Modern Library, New York. Thomas, D. H. 1975 Nonsite Sampling in Archaeology: Up the Creek Without a Site? In Sampling in Archaeology, edited by James W. Mueller, pp. 61-81. University of Arizona Press, Tucson. Thornwaite, C. W. 1948 An Approach Towards a Rational Classification of Climate. Geographical Review 38:55-94. Tomka, S. A. 1998 The Chandler Collection, Prehistoric Artifacts from Ellis and Navarro Counties, Texas. In Archaeological Investigations in Support of the Superconducting Super Collider, Ellis County, Texas, by J. L. Yedlowski, K. L. Shaunesey, D. H. Jurney, and J. M Adovasio. Archaeology Research Program. Mercyhurst College, Erie Pennsylvania. Trigger, B. G. 1989 A History of Archaeological Thought. Cambridge University Press, Cambridge. Tylor, E. B 1871 Primitive Culture. John Murray, London. VanPool, C. S. and T. L. VanPool 1999 The Scientific Nature of Postprocessualism. American Antiquity 64(1):33- 53.

2001 Postprocessualism and the Nature of Science: A Response to Comments by Hutson and Arnold and Wilkens. American Antiquity 66(2):367-375. Wandsnider, L. 1992 Archaeological Landscape Studies. In Space, Time, and Archaeological Landscapes, edited by J. Rossignol and L Wandsnider, pp. 257-282. Plenum Press, New York. 1997 The Roasted and the Boiled: Food Composition and Heat Treatment with Special Emphasis on Pit-Hearth Cooking. Journal of Anthropological Archaeology 16(1):1-48. Winterhalder, B. 1981 Optimal Foraging Strategies and Hunter-Gatherer Research in Anthropology: Theory and Methods. In Hunter Gatherer Foraging Strategies, edited by B. Winterhalder and E. A. Smith, pp. 13-35. University of Chicago Press. Winterhalder, B. and E. A. Smith 1981 Preface. In Hunter Gatherer Foraging Strategies, edited by Bruce Winterhalder and E. A. Smith, pp. ix-x. University of Chicago Press. Winterhalder, B. and E. A. Smith 1992 Evolutionary Ecology and the Social Sciences. In Evolutionary Ecology and Human Behavior, edited by E. A. Smith, E. A. and B. Winterhalder. pp. 3-24. Aldine de Gruyter, New York. White, L. A 1943 Energy and the Evolution of Culture. American Anthropologist 45:335-356. 1959 The Evolution of Culture: The Development of Civilization to the Fall of Rome. McGraw-Hill, New York. 1973 The Concept of Culture. Burgess Publishing Co. Minneapolis.

Whittaker, C. R. 1993 The Poor. In The Romans, edited by A. Giardina, pp. 272-299. Translated by L. G. Cochrane. University of Chicago Press, Chicago. Woodburn, J. 1968 An Introduction to Hadza Ecology. In Man the Hunter, edited by R. B. Lee and I. DeVore, pp. 49-55. Aldine Atherton, Chicago. 1970 Hunters and Gatherers: The Material Culture of the Nomadic Hadza. Trustees of the British Museum, London.

Andrew F. Malof was born May 30, 1959 to Joseph and Delores Malof, in Santa Monica,

California. The family, including sister Jessica, moved to Austin, Texas in 1960, where

brother Peter was born. Andrew graduated from Austin High School in 1976, and pursued

various vocations, including raising a family that includes son Jacob, born in December,

1980. He returned to school full-time in 1993 and received a Bachelor of Arts Degree in

Anthropology and Archaeology in December of 1996. In May of 1996 he was hired as an

archaeologist at the Lower Colorado River Authority in Austin, Texas. This position led to

numerous publications which are on file at The Texas Historical Commission and at the

Texas Archeological Research Laboratory, both in Austin. He has also published in the

Bulletin of the Texas Archeological Society and in La Tierra, the Journal of the Southern

Texas Archaeological Association. In September, 1998 he was accepted into the Graduate

Anthropology Program at the University of Texas at San Antonio. He is currently still

employed at the Lower Colorado River Authority.

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