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Vortrag im Rahmen des 6. Internationalen Kongress für Ganzheitliche Tiermedizin e.V.April 24, 2006.

The science of zoopharmacognosy:what do we know about animal self-medication?

Tedje van Asseldonk(mrs drs A.G.M. van Asseldonk),

Institute for Ethnobotany and Zoopharmacognosy (IEZ),Rijksstraatweg 158, 6573 DG Beek-Ubbergen, the Netherlands.

Tel. +31.2468.44301; fax 2468.43939.www.ethnobotany.nl ; info@ethnobotany.nl

Outline of speech

IntroductionHistorical remarksResearch by Huffman et al. (primates)Research by IEZ (primates cattle)Other animal speciesAnecdotical reports about petsWhat can we learn from this?

Introduction

This morning I will try to teach you somethingabout the rather new science ofzoopharmacognosy. I will give a globalintroduction showing several examples.Let my introduce our small institute first.About 10 years ago my colleague Arend de Haasand I founded our institute the IEZ in theNetherlands, because we thought these twoimportant issues received too little attention inDutch universities. Ethnobotany is the study oftraditional herbalism, and Zoopharmacognosy isour subject of today. There are someethnobotany students in our universities, but theyalways work abroad, mostly in the third world.However important this work is, we believe thatwe also need to turn back to our own historicaland folkloric herbal tradition, we will have to studythat carefully, and we will need to re-evaluate and

revalue both the concepts and remedies of thattradition with our modern knowledge. Only bydoing so we can hope to communicate on a basisof mutual equality with the people in the thirdworld. Then we can really learn form each otherand help each other. So we concentrate onresearching all these things in the Netherlands.Today we will concentrate on ourzoopharmacognosy work.

The outline of my presentation will be as follows:- After a short Introduction I will give somequotations from old books about animalselfmedication.- I will continue with an overview of the work byHuffman and others on primates;- Then I will discuss our own research onprimates; and explain how we are setting the firststeps on research on cattle.- Very briefly I will touch the subject ofzoopharmacognosy in other animal species andgive some anecdotical reports about pets.- In the end we can maybe have some discussionabout: What can we learn from this? How do weproceed to extend our knowledge?

To finish my short introduction I will show you ourongoing projects. I will only talk aboutzoopharmacognosy now; but I will refer to theother projects when appropriate.So now we start with our first issue, beingEuropean history.

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HistoryHere we have an example of a poem of thefamous Dutchman Jacob Cats, he is also namedFather Cats, because he has teached to a lot ofDutch people about the moral values they had tocherish. He wrote more than one poem about thewisdom that animals have about herbal healing,but this emblema is also in English, and thereforemost suitable for this occasion.It is called: No help for the lover, and it says:

The hert that wounded is, knows how to fiendreliefAnd makes by dictamon the arrow out to fallAnd with the selfsame herb hee cures his woundwithallBut love no herb can fynd to cure his inward grief!(as we can see on this picture of amor)!

It is an interesting reference that he makes to thisplant Dictamnus; it was in fact Dioskorides, theGreek author of the most authorative herbal inEurope, written in the 1st century A.D., whoalready stated that chamois (mountain goat),when they are wounded by an arrow, eat fromthis herb to expel the remnants.

Let's look at some more examples. Plinius (theRoman author, in his book on Natural Historyabout 77 A.D.) also mentions this Dictamnusstory and tells us that much knowledge stemsfrom the observation of animals. For example hestates that the clystre (enema) was an inventionof the Egyptian Ibis birds; they use their bills tosquirt water in their ass to clean their body's. Iwould not know if this is the case, but he statesthis observation and many more. When harts arestung by a poisonous spider, they eat fresh watercrabbes to cure from it. If by accendent they eatpoisonous weed, they cure themselves withArtichokes (as we now know: this is good help fro

the liver). When a scorpion is poisoned bytouching Aconitum, he uses Helleborus to heal.And the swallows use the orange colored (bitter)juice of the plant Chelidonium for the eyes oftheir young. The weasel uses Ruta as apreservative when he goes on a rat huntingmission. The snake uses the juice of Fennel byrubbing herself with it; both for skin change andfor better eye sight after the winter. The dragon(whatever he means by that!) when overloadedits stomach with meat finds relief in the juice ofthe wild Lettuce. Storks use Oregano when theyare ill, and bears use Hedera helix (ivy) andCrabfishes, and Plinius gives a detailed accountof several plants used by several animals forpurging and cleansing the intestines.

The famous blood pressure-lowering plantRauwolfia serpentina had come into use forsnakebites, because people in India saw theEgyptian mongoose (Herpestes ichneumon) eatthis root before it was attacking a cobra. The riseof the Christian religion may have put these typeof observations more to the background. InEurope views were modified because theChristian God was sometimes seen as theinspiring entity for the use of medicinal plants, orgreek/roman era physicians, but certainly notanimals. Also disease was sent by God andtherefore sick people needed care, not cure.In in the Renaissance period in Europe the olderzoopharmacognosy observations were againrecognized, for example by Brunfels (1532) whowrites that the leaves of Laurus nobilis are usedby pigeons and chickens to cure constipation, anexample that was also given by Plinius. Erasmuswrote in the Colloquia that he had observed atoad, who, after he was bitten by a spider, tookinstantly a leave of plantain (Plantago).(Noordhuis 2005).Many examples were given by Gianbattist de laPorta (1558), who was one of these allroundscientists that were physician and alchemistamongst other things. For example, says Porta:the elephant, having eaten a chameleon, eatswild olive against its poison (the same thing ismentioned by Plinius). For wounds it would useAloe.The mainstream mechanistic approach in theEuropean science of the 17th, 18th en 19th centuryhowever described animals as machines withoutany thinking or feeling and so thezoopharmacognostic lines of thought becameobsolete in science.

But in the 20th century two lines of research cametogether. Ethnobotanists, working in severalcountries, noticed that the indigenous people in

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other continents often pointed to the animals (forexample primates in the Amazon region) as thesource of their herbal knowledge. Again it wasremembered that the North American Indians,when asked where their herbal knowledge camefrom,.had pointed to the bears. Indeed severalmedicinal herbs are named after bears like Alliumursinum, Arctostaphylus uva ursi etc.The folk animal herbalist Julliette de Bairacliwrote about some examples of animal selfmedication in her books. It was Jane Goodallwho reported, together with Richard Wrangham,some actual cases of self medication by chimpsin Tanzania, that got to the media and raisedpublic interest.

Huffman et al. on primatesThe ethologist Huffman of Kyoto University inJapan took up this type of research verydiligently. He took several samples of plants tothe pharmacognosy laboratory, plants that wereapparently used by chimps for self medicationThere the existence of medicinal compounds inthese plants was confirmed. Other examples ofthis research in the end of the 20th centuryinclude a report from Washington universitybiologists about zoo capuchin monkey Alice. Sheapplied several times corn syrup with a stick onher wounds.

The new science, a combination of ethological(animal behavior) and phytochemical(pharmacognostical) research was namedzoopharmacognosy by Eloy Rodriguez. Researchby Huffman, Sauther, Carrai, Kriege and othersshowed the phenomena to be rather complicated.According to Huffman (2005) not only chemicalstrategies but also physical (mechanical) effectsof plant parts may play a role in their usefulnessto combat parasites.

Two phenomena Huffman reported were “bitterpith chewing” and “leaf swallowing”.November 1987 Huffman noticed a femalechimp, of a group that he had followed for severalmonths, was feeling weak, she hardly left her bedand took no care of her young. Later she went toand sat down in front of a shrub and pulled downseveral new growth branches. She placed themall on her lap and removed the bark and leaves ofthe first branch to expose the succulent innerpith. She bit off small portions and chewed oneach for several seconds at a time. By doing this,she made a conspicuous sucking sound as sheextracted and swallowed the juice, spitting outmost of the remaining fiber. This continued for 17minutes, with short breaks as she consumed thepith of each branch in the same manner. This

plant was Vernonia amygdalina, and it wasobviously not a regular part of the chimps diet.Huffmans local assistant Mohamedi was from ahealer's family and knew this plant wasconsidered a strong medicine against malaria-fever, stomach-ache and intestinal parasites.Within a day the chimp recovered from herillness. After this event Huffman looked for andfound other examples.A particularly interesting phenomenon was thathe saw chimps swallow whole leaves of Aspiliaplants. The leaves are folded between tongueand palate and pass visibly unchanged throughthe gastrointestinal tract. This is often done asthe first, or one of the first, food items in themorning. Although laboratory analyses foundchemicals with potential antibiotic andnematocidal properties in the plant (findings thatwere later challenged) clearly they could not playa large role, given the fact the leaves left thebody undamaged. Several field observationscould link this behaviour to the expulsion ofparasites. These kind of activities are alsoreported for other animals. And moreover itappeared that in the rainy season, when parasiteloads are heavy, this behaviour increased. So itmust be a kind of purging therapy, for which theanimas choose specific plants, plants with arough or hairy surface. They take the worms withthem on the way through the intestines. Althoughsome chemicals may be involved, this mainly is aphysical strategy against worms.So Huffman mentioned several strategies forplant use, and also he introduced the link toethnobotany, local herbal knowledge. He andothers have also looked for herb use in specificconditions like pregnancy, I will talk about thatlater.

Research by the Institute for Ethnobotany andZoopharmacognosy (IEZ)

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In 1995 several articles in Dutch newspapers hadbeen discussing the knowledge that woollymonkeys (Lagothrix lagothricha) appear to haveon the medicinal plants, growing in their outdoorenclosure in the zoo Apenheul. Therefore the IEZinstigated field studies in this zoo during 1996and 1997. During the years 1998-2002 weobserved the foraging behavior of Boliviansquirrel monkeys (Saimiri boliviensis), both inApenheul and in the French zoo "Vallée desSinges".

Study groupsPreliminary studies included an inventory of thevegetation and an estimate of the bite size forLagothrix lagothricha and several observationalad libitum and scan sampling studies (Altman1974). The woolly monkeys (Lagothrixlagothricha) we studied in Apenheul PrimatePark were part of a group of 18 females, somejuveniles and two babies that was free rangingbetween visitors. In the spring of 1996 weobserved 8 adult females for ten days by focalanimal sampling (8x10 observer days). Weobserved 4 individuals in a 20x4 days spreadthrough the opening season in 1997. TheBolivian squirrel monkey (Saimiri boliviensis)groups in Apenheul primate park (NL) and Valléedes Singes (Fr) consisted of about 100 (NL)respect. 50 (F) free ranging individuals. Themonkey enclosures that we studied are eachabout 10,000 m2, several vegetable plots dividedby asphalt walking roads.MethodsAn inventory of the vegetation was made in orderto compare it to the consumption. To study theforaging behavior for Lagothrix lagothricha focal(continuous) sampling was used (Altman 1974).For Saimiri boliviensis we applied ad libitum(continuous and location fixed) sampling. Thestatistics we used were summarizing anddescriptive.ResultsIn the woolly monkeys (Lagothrix lagothricha)area we found 123 different plant species (somecould not be specified beyond genus level)belonging to 53 plant families. To make thisquantitative, and comparable to the consumption,we estimated of all plants present the amount ofbites that were available for eating. To estimatethe size of a bite three observers imitated themonkeys foraging behavior, carrying out 10x10samples for each item. So a bite of a herb wasestimated to be 2,3 (+/- 0,8) gram; a tree or shrubleaf bite was smaller; a bite of grass was 3,9 (+/-1,8) gram. The total amount of available bitespresent for Lagothrix lagothricha in the enclosure

we estimated to be a total of 25,215,468 bites(6090 kg).I like to add that this was an early seasoninventory. Probably in summer more bites wereavailable.The squirrel monkey Saimiri boliviensisenclosures were not quantified for the vegetation.They were rather new plots and the list of plantspresent was available in Apenheul. There wereover 97 different species planted, and in thearea's used for observation we noted thepresence of 46 species.

For the woolly monkeys (Lagothrix lagothricha) in1996 the consumption of 43 (and in 1997 of 44)different plant species from the wild wasreported. There were large differences in plantchoice between individuals and between specificdays.The average plant consumption in both yearswas about 7 g/animal/hour (22 bytes/hour);additional 4-6 insects/hour and 2 bites of sand,pebbles or clay were consumed on averageevery hour.

About 25% of the plant consumption in bothyears we found to be of the Fagaceae family.Equally available were Quercus rubra and Fagussylvatica. Yet consumption of Quercus was 3 fold(1997) to 10 fold (1996) that of Fagus. There wasalso a substantial consumption of Berberis spp(10-15%). The preference in the consumption oftrees and shrubs appeared to be ratherconsistent amongst the group members. Therewas more animal specificity in the choice ofherbs. Summarizing we noticed specific herbpreference for plants of the Asteraceae,Caryophyllaceae, Rosaceae, Boraginaceae andUrticaceae families and these plants are mostlywell known medicinal herbs in the Dutch herbaltradition..

To illustrate this I will now make a short remarkabout an earlier project that gave us a goodoverview of traditional Dutch herbalism. Wemade an inventory of plant families with relativelymany medicinal herbs in the Netherlands (VanAsseldonk 2001). To this aim we compaired on aplant family level the Dutch flora with allmedicinal plants mentioned in the most popular20th century Dutch herbals. So it was the samekind of study only with humans in stead ofmonkeys and we used the books in stead of afield study. Some plant families that cameforward the Dutch share with all North Europeancountries as is described by prof. Moerman(Asteraceae, Lamiaceae, Apiaceae) but some

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seem to be typically Dutch (e.g. the medicinaluse of Rosaceae plants).It may not seem very much if an animal eats 2 or3 bytes of a herb. But the dosage of theseincidental bites is quite proportional to the humandosage when using these herbs as a foodsupplement or a home remedy. 2 bytes = 5 g/day(fresh) is about 0,5 g/dry = +/- half of human dailydosage for many herbs.Herbs we noticed to be consumed includedamongst others: Taraxacum officinale, Matricariachamomilla, Urtica spp, Plantago spp, Impatiensparviflora, Rumex spp, Aegopodium podagraria,Glechoma hederacea, Trifolium spp, Fragariavesca, Myosotis arvensis, Stellaria media andPolygonum spp.

With Bolivian squirrel monkeys (Saimiriboliviensis) consumption was seen of 17 (in2000); 19 (2001) and 16 (2002) different plantspecies. Also for these monkeys a great deal ofthe foraging behavior concerned catching ofinsects: about 8 % (2000); 10 % (2001); 12 %(2002) of the total amount of bites. Thesemonkeys have a preference for grass, flowersand flower- and leaf buds (Rosa spp, Silenedioica) and nuts and other parts of Fagussylvatica. We noted about 10 bites an hour.

Conclusions of our primate research* the monkeys seem to make a selection from theavailable plant species within the outdoorenclosure; although we could not establishhealth-consumption relations there was not an atrandom consumption; also there was veryindividual-specific consumption* certain plant species like barberries, oak andgrasses are frequently eaten by all theindividuals. This suggests these are nonspecific,additional food items.* Other plant species are consumed incidentally;the differences between separate days andindividuals are enormous. And these are typicalthe human medicinal plants in our folk herbalculture. So in this respect selfmedication COULDplay a role, but we have yet no actual PROOF itis health promoting.* the dietary supplement that is achieved throughspontaneous foraging included an unexpectedlarge amount of animal prey; this has given riseto an increase of protein that is supplied throughdiet for the woolly monkeys in the Zoos; they getextra eggs and insects.* the monkeys frequently eat inorganic materiallike sand, eart h and pebbles. The function of thishas not yet been established, this could be amineral supplement, or a detoxification, or even acombination of these and other factors. Once I

folllowed a female with a young, she was knownto consume lots of cement, so she did when shediscovered a heap of it, and I saw her forbid thebaby to eat it (while there was enough!).

* the spontaneous foraging in the Zoo is aninteresting complementing diet factor, that couldbe health promoting by offering * *additional micro-nutrients for exampleminerals or the anti-oxidants that are present in''wild vegetables'‘ * *adaptive individual-specific corrections to thesupplied food and the possibility for active copingbehaviorSpecific cases of sick primates that use bitterherbs as were reported by Huffman (2005) wedid not find in the Zoos because for obviousreasons sick animals were not allowed to mixwith visitors.

In the search for specific health relatedconsumption several primatologists have lookedinto the differences between pregnant and nonpregnant (lactating) individuals. It is well knownthat lactating females have to consume morecalories, but the specific different type of food isnot so easy to explain. For example MichaelleSauther did a study on lemurs in Madagaskar.She noticed differences in leaf and fruitconsumption between males and pregnantfemales. Another (more recent) example is thestudy of Carrai et al. that is closer to the subjectof today. These researchers have addressed theproblem by taking samples and analyses ofspecific compounds of the plants. In this case thepercentage of condensed tannins was analyzed,both in the vegetation present and in the foodused. Here also there are remarkable differencesthat cannot be easily explained. My suggestionwould be that maybe the tannin content itself isrelated to the flavonoid content and that may berelated to the estrogen content. Maybe we canshed some lights on things like that in our studywith cattle that we have just started.

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Research by the Institute for Ethnobotany andZoopharmacognosy (IEZ) II. Cattle

From 2001 onwards we have students studyingconsumption of medicinal plants by grazing herdsin nature reserve area's in the Netherlands. Herewe hope to register more specific cases of sickanimals behavior in relation to medicinal herbs,because the owners let very much nature haveits course. But also we want to look into specifichealth challenging situations to see how theanimals adapt. First I will show you the situationin a glance.

The grazing herds that we study at this moment(Konik horses and Galloways cattle) have a largearea of free ranging, in between 45 and 700 haeach. The method used is again focal animal(continuous) sampling. Herd sizes vary from 10to 50 animals.

At this moment we are still in the process ofsampling single case studies for these animals.Already some specific behavior was registered byus (IEZ) and others. This concerns for examplethe consumption of herbs known to be toxic, likeColchicum autumnale, Conium maculatum andConvallaria majalis. It has been demonstrated byProvenza et al (2003) that cattle can combine twotoxic species of herbs into useful food.Palatability is the interrelationship between afoods flavor and its postingestive effects (bothnutritional and toxic) and dosage makes apoison. Animals have a very effective feed backmechanism. For example they can learn tocombine two toxic foods into a less toxic meal.An example can be tannins and alkaloids thatdetoxificate one another. And liver and kidneyhave many mechanisms for detoxification. Butdetoxification for animals has a price in energyand they must be given some food choiceopportunities.

There are mostly three or more parties involvedwith the grazing herds:- the owners of the land, mostly nature conserveorganisation or gouvernment organisation. Theirconcern is mainly the way the animals manage tokeep the grass short. For example in the NL it isimportant that these areas can take enoughwater volume in winter when necessary. Toomuch vegetation would prevent that so thegrazing herds will have to serve as lawn moiers.- the owners of the animals and theirveterinarians; they mostly are concerend aboutwhether the animals have enough to eatespecially in winter, most of the times there is nointerest in the medicinal herbs, only a fear fortoxic herbs.- the third party are the scientists involved. Asyou might know herbalism and all other kind ofnaturopathy is in Holland very much ''not done''on universities, so universities stick to the firstitem, maybe the second (but rarely) whereas thethird item is specifically our field of study.

Now from other scientists we got some overviewsfor example this one by TheoVulink.

That shows there is interesting season specificconsumption. You see there is a remarkabledifference between uses of browse , herbs, reedand grass in the specific months of the year. Atthis moment my students are filling up somemissing months here.We focus on plant use in early and latepregnancy of cattle. We had several anecdoticalreports about cows- that ate Rumex spp (burdock) after loss of acalve- that ate more Urtica spp (nettle) around birth- that ate Arctium lappa stems (and leaves, butspecific the stems) around birth

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That is why we expect to find changes in foragingbehavior related to the pregnancy condition,changes that provide for individual adaptions inthe selection of food. This may have a relation tothe hormonal effects of plants. This is acomplicated matter, and I will try to explain someof it.

Avoidance and chemical ecologyI will tell you something about the chemicalecological background of this type of research.The pharmacological effects of plants areexplained by their secondary compounds. Thename secondary compounds distinguishes themfrom the primary plant compounds that are mostimportant for the metabolism: proteins,carbohydrates, fatty acids, nucleic acids, etc.Biologists explain the presence of thesecompounds as one of possible ways that plantsdefend themselves against grazing and otherattacks. Several mechanisms can be applied inthis plant defense:

1. Avoidance: they can have a low growing point(monocots); so we see very few toxic and hencemedicinal aspects in these plants; the importantfood plants wheat rice mais etc are in this group.2. Hairs, spikes, thorns, etc (dicotyledones);roses etc invest not so much in toxins either3. Reduced digestibility: by compounds like

(hemi) cellulose (large CH), silica (Si), ligninsand tannins (polyphenols), in general largecondensed structures, or on the other handby proteinase inhibitors (Solanaceae) ormore general inhiibiters of theparasympathicus

4. Then they can make toxins: alkaloids,terpenoids, glucosinolates, cyanogens,(steroid) saponins, lectins (protein),coumarins, etc.

5. Or (and that is recently gaining more and moreinterest) they make (also) chemicals that help torepair damage by free radical damage, heat etc:(iso)flavones, anthocyans, etc. (anti-oxidants).

Now they found out that the synthesis of thesesecondary plant compounds is often induced byinsect attacks (phyto-alexins), drought-stress,etc. And that the pharmacological effects of thesecompounds vary but mostly:

- in a low dose they are beneficial (they cancorrect small health problems)- and in a high dose they are poisonous (theycan give drastic changes)

Nearly all known medicinal effects of herbs (inhuman medicine) are related to specific effects ofthese (many, different) compounds. Animals will

need to have access to a diversity of plants tooptimise their health.I will now just take ONE example of the verycomplex plant-animal interactions due to thepharmacological effects of some of thesesecondary plant compounds. We know that someof them look like oestrogen and act like this.Phyto-estrogens are more or less hormone-identical structures; inhibiting or triggeringhormone receptors:- They can have anti-hormonal activity orhormonal effect; antihormonal when they onlyblock the receptor; hormonal when they trigger it.What will be the effect is also a result of theconcentration of these and other compounds,condition of intestinal flora and unknown factors.Examples of chemical structures; the distancebetween these two OH groups (phenol on C3 andalcohol on C17) is important, if it is 1,1-1,2 nmand the structure in between is hydrofobic, nottoo flexible, it will probably fit the oestrogenreceptor.Also we know that isoflavones compete morewith estradiol on beta-receptors (BBP) than onalpha-receptors (PRK)- They belong to several phytochemical groups:lignans, polyphenoles,(iso)flavonoids, steroids,alcohols.- They are present at a high level in Leguminosae(Fabaceae) family (e.g. Trifolium subterraneum /T. pratense caused infertility in sheep); but alsoin many other families (e.g. Apiacea, Lamiaceae,Asteraceae, Moraceae, Brassicaceae,Rosaceae)- They are sometimes present as a fungotoxin asa result from specific environmental conditions,for example in hay, mais or grass because ofFusarium roseum root fungus (Groot, 2003). Thisfungus makes Zearalenon, a mycotoxin with verystrong oestrogen effect that can cause seriousproblems in animals.I show you just for a moment the long lists ofplants with these kind of possible activities; theseare all plants that the animals actually can use intheir environment in the NL.

We now only talked about estrogens. But anotherinteresting story can be told about plants thathave oxytocin activity or other uterostimulatingproperties (for example Viburnum, Arctium lappa,and strong aromatic plants like Tanacetum,Artemisia or Chamomilla species) plants withergotamin like activity (Capsella bursa pastoris,Urtica leaves) and plants that have uterospasmicacitivity (for example Oenothera biennes,Quercus and Salix, and several Solanaceaspecies).

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We hope to document uses of these plants bycattle in our ongoing field study that focuses onpregnant cows.

Other animal speciesIt was reported to us that shepherds had beennoticing that sheep tended to eat dandelionflowers, plantain, or burdock leaves when theywere weak. They brought them to a place wherethese plants were available to them when theyfelt the animals needed it.

One of my students works in a goat farm and shesaid there was after delivery a noteworthconsumption of Anthriscus sylvestris (cowparsley or wild chervil). Now this is a herb notknown for its medicinal properties nowadays, butI found in the old Fuchs (Renaissance herbal)that it is used to expell better the placenta(afterbirth).

In the old days it was common that people usedaromatic plants in their houses, especially whenthere were ill people around, to diminuish the riskof infections. Lately several ethologists showedthat birds do the same thing: they use aromaticherbs in their nests to protect their young. Thiswas shown for starlings by Gwinner (in 2000): thebirds use specific herbs, they do not takeBrassica's (that smell like mustard) but they takeextra time to look for aromatic plants like Achilleamillefolium (yarrow), Daucus carota (wild carrot),Agrimonia spp., Erigeron spp , Solidago spp(goldenrod). These plants did not cause areduction in endoparasites, but the green nestshad stronger young, that had a higher amount ofhaemoglobin in their blood.

For blue tits it was shown by Petit et al (2002)that olfaction is used to discriminate and selectthe plant substances.

Recent also ant researchers have joined thediscussion; Christe et al (2003) showed that antsthat use conifer rasins in their buildings have anadvantage above those who are prevented fromdoing so, because they suffer less growth ofmicro-organisms.

Anting is a well known phenomenon amongstbirds. They rub themselves for example withmillipedes (recently it was confirmed that themilliped toxins do not actually kill the ticks, butthey are slowed down by it and cannot climb for along period, even at a low dose ofbenzoquinones, which is the millipedes poison(Carroll et al 2005.). The behavior of birds incaptivity using sigarets, orange peels and all

kinds of stuff for the same purpose is very wellknown.

In 2002 Cindy Engel, an English biology teacher,published a book called Wild Health where a lotof examples of selfmedication for several speciesof animals were brought together. In theNetherlands some researchers were inspired byher book and in 2004 a study with pigs was setup. A choice of three herbs was made availablefor pigs; the setting was meant to comparegroups of dewormed pigs with groups of non-dewormed pigs, but as it was unknown if theseherbs actually were effective against worms; andthere was no difference visible between the twomain groups, and also there was not much worminfection, this line of research was not continuedin the NL but it is in Germany by the KasselUniversity (professor Ton Baars).

Anecdotical reports about petsWe receive many anecdotical reports of specificbehavior of pets and horses regarding thespontaneous consumption of herbs. Mostly thisconcerns craving, even digging out of the earth,of certain herbs by one animal, wheras itsrelatives do not show any interest in the sameherb. Also some herbal folk remedies have azoopharmacognostic origin (Van Asseldonk andBeijer, 2006). One student reported a case of awoman who made a digestive tea from someherbs for herself. Her cat came and drank from it,whereas she normally didn't do this. The eventwas repeated a few times and the woman noticedan improvement in the cat's appetite. Also thecat's chronic vomiting and diarrhea ceased. Theremedy was also effective on the rare occasionsthe digestive problems returned in later years.There was a dog who used to dig up and eatfrom roots of a Thuja occidentalis tree. Theanimal had several health problems and wastreated by one of my students with ahomeopathic Thuja preparation, then thebehavior disappeared and the health restored.

Especially horse owners often call or send me e-mails about strange cravings. For example theyhave two horses, one is a nervous kind, it eatschamomilla, whereas the other hates this herb.The same thing goes for nettles and thistles;there often is a connection with kidney or liverweakness, if you ask for it. Once there was ahorse that had ruined its back with too harsh atraining, that was eating Heracleum sphondylium,only in the period of recovery. No other horsesseemed to like it; however I had also anethnoveterinary case report on this plant being aroborans for horses. Two horses out of a group

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that suffered from fly-eczema consumedEpilobium spp, whereas the other horses had nointerest in these herbs.

A phenomenon that is very well known, butpoorly understood, is the consumption of grassby dogs and cats. A lot of hypotheses are to befound in popular media, it could be the need forthe contents of the stomach of the herbivorouspray, it could be purging, maybe also a physicalworm expelling, this was seen by goose, brownbears and wolves. None of these hypotheseshave been tested. That is why at this momentthere is an ongoing study from the university ofCalifornia where pet owners are asked tot join itby filling in a questionnaire on their website. Ofcourse we had many reports about thisphenomenon, and I have observed my own dogshowing this behavior, therefore I know for mydog, and for some others, it is a specific kind ofgrass they need; he checks the roughness (andnot the taste!) with his mouth. He decides forElymus species (it's not like he knows thatElymus caninus, cough grass, was named afterhim; he also takes Elymus repens, which by theway is a traditional medicinal plant. Else he alsotakes some Carex species, whose leaves havean equally rough structure.

Other animals, as mentioned by a.o. Engel, usegrass or carex spp to purge and diminuish theirworm loads: this is is seen in brown bears beforehibernating (lots of fibers and worms are to beseen in the dung); by wolves (roundwormsexpelled together with the grass) and by tigers:they do it to lose tapeworms.

Discussion on the implications: what can welearn from all this?We already mentioned the spontaneous foragingin the zoo as an interesting supplementing dietfactor, that could be health promoting by offeringadditional micro nutrients, for example minerals

or anti-oxidants, that are present in ''wildvegetables'‘ (Pieroni et al. 2002), and also byallowing the animals to make adaptive individual-specific corrections to the supplied zoo diet.

It is a well known fact that primates in anecodisplay, and horses and cattle in naturereserves, manage to keep themselves in a morehealthy state when compared to cages or farmanimals.It has also been established that that cows thatcan graze freely outside produce milk that isricher in unsaturated fatty acids, rumenic acidand vaccenic acid, than cows that are keptindoors; even when they are fed freshly mowngrass. But what role the availability of certainmedicinal plants plays for each animal is difficultto establish. As the individual-specificadaptations, that the animals make by theirspecific food choice, give the researcher manyconfusing data, it is very difficult to provestatistically that their food choice is healthpromoting. Yet most zoopharmacognosyresearchers share the opinion that what is to belearned from the animals is ''health promotion''rather than ''combating illness''.

SO,What did we learn?1. Animals relate to medicinal herbs, more in away that keeps them healthy, than in a way thatcombats disease (so: prevention is better thancure) How they do this, how we can make holistichealth portraits of the animals and combine thiswith the integral pattern of their herb use, is still achallenge to us. We hope our new analyses ofthe traditional herbalism can help us out here.2. There is more than one way to skin a cat: thechemical combating or supplementing strategiesare only two of the possible medicinal strategiesthat a plant can be used for; other strategies areof a physical nature (for example rough leaves toinduce vomit, or to expell worms), and theremaybe other uses we don’t know of yet, such asinformational use (for example homeopathic use,or some messages about climate and soil thatanimals get from plants)3. It may be important to give animals thepossibility to make individual adjustments to theirdiet; and also give them the chance to performmore natural behaviour by ''hunting'' for foodthemselves.It seems obvious, but this of course will have tobe proven, that the fact that the animals are ableto care some care for their food supply bythemselves give them less stress and a betterhealth. We know from human health care thatactive coping is very health promoting and that

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for people having less grip on your situationmeans more stress and this is bad for generalhealth.

What should we observe?There is a lot to see and a lot to learn for thosewho are open minded.Huffman gave us this list of clues, that maysuggest self medicative behavior:

1 unusual eating behavior (swallowing withoutchewing; eating parts with no food value, verybitter tasting parts)2 use of plants that is very specific related to acertain season or a certain place (look for arelation with a parasite load; with birth cycle etc )3. specific use of a plant when an animal is ill(plants that are normaly avoided) ; may be (ormay not be) followed by restoring health4. the use of plants that are specifically wellknown because of their medicinal effects (I musthowever add that, when you study more andmore books about herbalism, you will hardly everfind a plant that has NO claims of medicinalvalue)

A lot is known about pharmacological effects ofsecondary plant metabolites. The science ofpharmacognosy in our country has nearlydisappeared, but natural product chemistry,metabolomics and chemical ecology take itsplace. The last mentioned science we consider tobe an important bridge between concepts oftraditional herbalism and modern science.

I cannot go any deeper into this now, but just in ablink I will show you this. In another study weperformed on traditional European herbals wefound a relation between the philosophicalconcepts in traditional herbalism (thehot/dry/cold/wet classification) and the secundaryplant compounds involved. The interesting thinghere is that traditional herbalism has concepts forrestoring health (rather then combating disease)and is individual specific, so this may give usclues for understanding the health promotingplant choices of animals.

Zoopharmacognosy may serve as an eye-opener; it does not provide fix and ready recipesyet, it is still in the phase of anecdoticobservations.But, we will have to realise, that all behaviourtakes part in health promotion, or constituteshealth risks, this goes for both humans andanimals.

Thank you very much for giving me theopportunity to talk with you about my work!

References:- Altmann, J. 1974. Observational study of

behavior: sampling methods. Behaviour49:227-267.

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