Dietary practices convey valuable information on ethnicity, gender, and social differences between and within archaeological populations. Through analysis of human bone carbon and nitrogen stable isotope ratios from the Rio Muerto site, we reconstruct the paleodiet of the Middle-Horizon Tiwanaku in the Moquegua Valley of Southern Peru and compare it to that of earlier and later groups. We also compare diet between gender and social subgroups of Tiwanaku. Results indicate a strong Tiwanaku dietary emphasis on maize, but minimal access to marine foods as compared to both earlier (Huaracane) and succeeding (Tumilaca and Chiribaya) populations. Tiwanaku males ingested significantly more maize than females, probably in the form of maize beer, but there are no gendered differences in access to meat. No significant dietary differences were detected between social subgroups.

ABSTRACT

Andrew D. Somerville, Paul S. Goldstein, Sarah I. Baitzel, Margaret J. Schoeninger Department of Anthropology, University of California San Diego

Paleodiet in the Tiwanaku Periphery:

Carbon and Nitrogen Isotope Data from Rio Muerto, Moquegua, Peru

TIWANAKU COLONIES AND THE RIO MUERTO SITE

TEMPORAL CHANGE IN DIET

Stable isotope analysis of carbon and nitrogen provide dietary information on ancient human populations. Stable carbon isotope analysis is useful in measuring the amount of C3, C4, and crassulacean acid metabolism (CAM) plant contribution to an organism’s diet (DeNiro and Epstein 1978). C3 plants have an average δ13C value of -26.5‰ while C4 plants, such as maize, have an average δ13C value of -12.5‰. CAM plants have similar values to C4 plants. Thus, maize consumers are expected to exhibit more positive bone δ13C values. Assays of δ15N values in organic tissues are used to distinguish between marine and terrestrial diets and to determine the relative trophic position of an organism or species (DeNiro and Epstein 1981; Schoeninger et al. 1983). Marine food sources have significantly higher δ15N values than terrestrial food sources (Schoeninger and DeNiro 1984), and 14N is preferentially excreted over 15N during metabolism, leaving animals with higher δ15N values than plants, and predators with higher δ15N values than herbivores. Within human populations, δ15N values can be used to assess differential access to animal protein sources. Sample preparation was conducted in Margaret Schoeninger’s Paleodiet Laboratory in the Department of

Anthropology and the University of California, San Diego. Bone samples weighing ~1 g were taken from ribs from M43 and M70 individuals. Crushed bone samples were demineralized in 1% HCL to isolate bone collagen and were soaked in 0.125 M

NaOH to remove lipids and humic acids. Isotopic analysis was conducted an automated fashion on a Thermo-Finnigan Delta XP Plus, Conflow and

Costect EA in the Analytical Laboratory at Scripps Institute for Oceanography (SIO) under the supervision of Bruce Deck.

Data are expressed using the standard formula δ = ((Rsample/Rstandard)-1) x 1,000 where R = 13C/12C or 15N/14N. The carbon sample was standardized relative to relative to the Vienna PeeDee Belemnite standard (V-PDB)

while the nitrogen sample was standardized relative to the ambient inhalable reservoir (AIR).

GENDERED FOOD BEHAVIOR IN TIWANAKU

TIWANAKU SUBSTYLES: OMO STYLE VS. CHEN CHEN STYLE DIET

CULTURE TIME N Avg δ13C PDB (‰) Avg δ15N AIR (‰)

HUARACANE 1200 B.C. – 700 A.D. 5 -15.6‰ 13.1‰

TIWANAKU 600 – 1000 A.D. 45 -12.2‰ 8.4‰

TUMILACA 1000 – 1200 A.D. 7 -12.9‰ 16.0‰

CHIRIBAYA 1000 – 1450 A.D. 151 -13.1‰ 16.5‰

HYPOTHESIS: Tiwanaku males are iconographically and contextually associated with patrimonial feasting and the drinking of chicha maize beer. Preliminary small sample studies suggested that Tiwanaku males had higher access to C4 foods (Sandness 1992). RESULTS: Analysis of 22 sexed adult samples from Rio Muerto confirm that Tiwanaku males consumed a significantly higher percentage of maize than did females (p=0.048). Including previously sampled individuals from Omo M10 (n=10) raises the significance level (p=0.009). However, there are no significant differences in nitrogen isotope values between the sexes. INTERPRETATION: Males may have participated more frequently in maize-centered rituals and feasting than women, a finding supported by the association of ceramic keros (goblets for chicha consumption) with male burials (Goldstein 2005:254).

HYPOTHESIS: Previous isotopic and ceramic studies on small samples suggest that the Tiwanaku colonists of Rio Muerto consumed a higher percentage of C4 food products and had limited access to maritime foods as compared to the previous Huaracane inhabitants of the Moquegua Valley (Goldstein 2003, Sandness 1992). RESULTS: Results of the Rio Muerto study substantially increase the Tiwanaku sample size and confirm that Tiwanaku colonists consumed higher percentages of C4 foods, and that marine foods comprised a smaller portion of the diet. The succeeding coastal Tumilaca population at Algodonal (Owen 2005, Sandness 1992) maintained maize foods in their diet, but included a higher percentage of marine foods. Tumilaca diet in the lower Osmore thus resembles the average for Chiribaya populations (Tomczak 2003), suggesting connections between the two groups. INTERPRETATION: Dietary results support interpretations of Moquegua Tiwanaku colonization as a productive colony dedicated to maize farming, with minimal access to marine foods.

HYPOTHESIS: The presence of two Tiwanaku ethnic communities inhabiting the Moquegua Valley during the Middle Horizon (Omo and Chen Chen) is suggested by differing ceramic styles, settlement patterns, and household configuration. Cultural differences could extend to different subsistence and economic strategies and culinary practices. In this study, individuals from Omo style contexts at Rio Muerto M70 and Omo M16 were compared to Chen Chen style individuals from Rio Muerto M43, Omo M10 and Chen Chen M1. RESULTS: The isotopic analysis finds no significant dietary differences between these two communities. Samples from different locations in the valley likewise showed no significant dietary difference. INTERPRETATION: If subsistence strategies differed between these communities, trade may have equalized access to food sources.

SUMMARY

The arrival of Tiwanaku settlers to the Moquegua Valley marked a stark change in dietary practices from the preceding Huaracane communities. The Tiwanaku diet included significantly more maize and minimal maritime input.

A significant dietary difference between the sexes indicates gendered food behavior. Males consume more maize, presumably indicating beer consumption in political feasting.

No significant dietary differentiation was noted between stylistic or ethnic subdivisions in the Moquegua Tiwanku colonies.

Portrait drinking kero depicting elite male, Chen Chen site M1. PSG photo

BIBLIOGRAPHY

METHODS: STABLE ISOTOPE ANALYSIS

Mummy from Rio Muerto M70,

tomb 1

Map of Rio Muerto settlements

M43 and M70, cemeteries in red

Map of Moquegua Valley displaying

location of Rio Muerto relative to other

Tiwanaku settlements.

Tiwanaku, the world’s highest ancient civilization center, benefited from access to temperate valley crops through a process of peripheral colonization in Moquegua and similar lowland valleys. Rio Muerto is one of four large Tiwanaku site groups that represent cosmopolitan townsites occupied from the 7th through 11th centuries (Goldstein 2005). The Tiwanaku colonization brought state-related intensive agriculture and social complexity and represents a dramatic break from the relatively egalitarian indigenous agrarian tradition known as Huaracane. Mortuary excavations in distinct cemetery sectors of the Rio Muerto site group (2006-2009) explored patterns of social and cultural differentiation within the Tiwanaku sphere. Ongoing research is focusing on within and between-cemetery variability in mortuary practice, offering traditions and bioarchaeology. This study compares the Rio Muerto Tiwanaku results with prior studies of local pre-Tiwanaku agrarian populations (Huaracane) and with post-collapse local societies that coud be descendent from Tiwanaku populations (Tumilaca and Chiribaya).

In situ mummy bundle from Rio

Muerto M43 cemetery A, tomb 44 0

5

10

15

20

25

-19 -17 -15 -13 -11 -9

δ1

3N

AIR

(‰

)

δ15C PDB (‰)

Huaracane

Tiwanaku

Tumilaca

Chiribaya

Left. Graph of dietary

signatures from southern Peru

over time. Data from this

study, Sandness 1992, and

Tomczak 2003. Error bars

indicate 1-standard deviation.

2

4

6

8

10

12

14

-18 -16 -14 -12 -10 -8

1

5N

AIR

(‰)

13C PDB (‰)

Female Male13C PDB (‰)

13N AIR (‰)

Top. Box plot of male and female carbon

isotope ratios. Bottom. Box plot of male

and female nitrogen isotope ratios

Scatterplot of male and female carbon and nitrogen

isotope values. Data from this study and from Sandness

1992. N=32 (females = 12; males = 20)

3

5

7

9

11

13

-18 -16 -14 -12 -10 -8

1

5N

AIR

(‰)

13C PDB (‰)

Chen Chen Style

Omo Style

Above. Scatterplot of carbon

vs. nitrogen stable isotope

ratios ordered by ethnic style.

No significant differences

exist between individuals of

Omo-style sites and Chen

Chen-style sites. N=45 (Omo

style = 18; Chen Chen style =

27). Data from this study and

Sandness 1992.

Chen Chen and Omo style keros, (PSG photos)

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and animal age. Geochimica et Cosmochimica Acta 48(5):1135-1140.

Owen BD. 2005. Distant Colonies and Explosive Collapse: The Two Stages of the Tiwanaku Diaspora in the Osmore Drainage.

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and Nitrogen Isotope Evidence. Lincoln, Nebraska: University of Nebraska.

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Schoeninger MJ, DeNiro MJ, and Tauber H. 1983. Stable Nitrogen Isotope Ratios of Bone Collagen Reflect Marine and Terrestrial

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ACKNOWLEDGEMENTS

We thank Patricia Palacios Filinich, Linda Yzurdiaga, Sarah Raubenheimer, Beth Plunger, the UCSD Rio

Muerto Archaeological Field School, and Wenner Gren.

(Algodonal)