Geophagy by brown bears in the Russian Far East

Ivan V. Seryodkin1,2,4, Alexander M. Panichev1,2, and Jonathan C. Slaght3

1Pacific Geographical Institute, Far Eastern Branch, Russian Academy of Sciences, 7 Radio Street,Vladivostok, 690041, Russia

2Far Eastern Federal University, 8 Sukhanova Street, Vladivostok, 690091, Russia3Wildlife Conservation Society, Russia Program, 17a Aleutskaya Street Apartment 31, Vladivostok, 690090, Russia

Abstract: Brown bears (Ursus arctos) occasionally engage in geophagy, the act of purposefullyingesting lithogenic mineral substances. From 1999 to 2013, we collected samples from 4,619brown bear scats from 3 regions of the Russian Far East (Kamchatka, Primorsky Krai,Sakhalin) in order to better understand geophagy in this species. Depending on region collected,soils were detected in 1–5.2% of samples. The greatest soil concentrations were found in scatsfrom Sakhalin in August and September, the same months when Pacific salmon (Oncorhynchusspp.) play a dominant role in seasonal brown bear diets there. Of the 207 Sakhalin scats with soilcontent, nearly all (87%) also contained fish remains. A chemical analysis of samples suggestedthat the soils being purposefully consumed by brown bears are clay-like substances from theilluviated soil horizon—minerals that most likely aid the bears in preventing diarrhea by helpingexcrete excessive amounts of phosphorus inherent in a fish-heavy diet.

Key words: brown bear, clay, geophagy, Kamchatka, kudur, Oncorhynchus spp., Primorsky Krai, Sakhalin, sal-mon, soil, Ursus arctos

DOI: 10.2192/URSUS-D-15-00014.1 Ursus 27(1):11–17 (2016)

Geophagy, the act of purposely consuming soilsfor some physiological benefit, is a phenomenonobserved across a variety of taxa, including reptiles(Sokol 1971), birds (Gilardi et al. 1999), herbivores(Worker et al. 2015), non-human primates (Krishna-mani and Mahaney 2000), and humans (Agene et al.2014). The benefits of geophagy include the introduc-tion of mineral nutrients otherwise lacking in a diet,toxin adsorption (particularly among herbivores thatingest toxin-heavy plant materials; Worker et al.2015), and the easing of gastrointestinal infection(Slamova et al. 2011).

Brown bears (Ursus arctos) often bury animal car-casses for future consumption, either in the grounditself or hidden under tree branches on the forestfloor. When subsequently eating such buried meat,the predator inherently ingests a certain amount ofsoil matter as well. In Russian brown bears, mineralparticles can also reach a bear’s digestive tract whenthey eat the roots of plants, Siberian chipmunk(Tamias sibiricus) pantries, nests of wasps (Vespidae),and in other food-procuring actions (Seryodkin2012). All such variations of ingestion of mineral

substances imply unintentional soil consumption(Panichev 1990, 2011).

However, soil substances can also reach a bear’sdigestive tract as a result of geophagy. Nasimovich(1938) noted that brown bears in the Kavkaz Reserve(Russia) appeared in autumn at a mineral lick (here-after referred to as a “kudur”—a place where animalsgo specifically to ingest mineral substances [Panichevet al. 2013]), which is a time when beech (Fagus spp.)and oak (Quercus spp.) mast predominated in thebrown bears’ diet. He speculated that bears did notvisit the kudur for the purpose of hunting ungulates,but rather to consume mineral substances.

We repeatedly observed geophagic behavior bybears at kudurs in the Sikhote–Alin Mountains of Pri-morsky Krai (Panichev 1987). This included a visualobservation in the upper reaches of the PeshcherkaRiver in June 1982, when a young brown bearapproached a kudur, sniffed about the exposed sur-face for some time, then scratched the clay substratewith its paw and licked it several times. The claywas smectite, with a significant proportion of zeolite(clinoptilolite) particles. The bear detected our pres‐ence after a few chews and then rapidly left the site.We also found evidence of soil consumption bybrown bears at a kudur in the Burlivaya River basin4email: seryodkinivan@inbox.ru

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(Primorsky Krai), including locations where thekudur was dug up by a bear paw and where water-logged soils were lapped at by a bear’s tongue. Inthis case, the consumed soils were disintegrated, tuf-faceous, sedimentary rock from the weathering zonewith interlayers of light, siliceous gaize (or fine-grained fragmental rock).

In the Sikhote–Alin Biosphere Reserve (PrimorskyKrai), 3 separate bear-scat piles consisting almostentirely of clay were found near kudurs in theKolumbe River basin and along Solontsovy Creek(O.Y. Zaumyslova, Sikhote-Alin Biosphere Reserve,personal communication). Soil consumption hasalso been observed by brown (5 grizzly) and Amer-ican black bears (U. americanus) at kudurs in theUnited States (Dixon 1959, Mattson et al. 1999).Evidence of geophagy by brown bears has beenrecorded at sites other than kudurs as well. Forexample, bears have regularly been observed ingest-ing soils along river banks and sea coasts during sea-sonal salmon (Oncorhynchus spp.) migrations(Nikolaenko 2003, Gordienko and Gordienko2005, Seryodkin 2012).

We have seen this form of geophagy on Kam-chatka and on Sakhalin. Particularly, we have repeat-edly seen bears, having apparently satisfied theirappetite on fish while moving along the water’s edge(river bank or sea coast), stopping, sniffing theground, and then using their forelimb claws toremove the ground surface layer and ingest smallamounts of soil. On occasion, bears selected locationsfor soil consumption some distance from the river orsea, including locations in the forest. From our exam-inations of locations visited by bears after consumingfish, some sampled soils included humus from thetopsoil horizon; but in most cases, the consumed soilscontained clay from subsoil horizons, either from silt–loam or sandy-clay alluvial or deluvial deposits.

We sought to address 2 objectives to better under-stand geophagy among bears: (1) to identify themost important food items from bear scats and toassess the proportion of ingested mineral soils; and(2) to conduct mineral and geo-chemical analysis ofsoils found in bear scats.

Study area and methodsWe collected all scat samples we discovered in 3

regions: (1) Primorsky Krai (specifically in Ter-neysky, Krasnoarmeysky, and Dalnegorsky districts,1999–2002); (2) Kamchatka (in Kronotsky Nature

Reserve, 2004); and (3) Sakhalin Island (VostochnyReserve, 2009–2013; see Fig. 1). We washed eachsample and sorted the components for identification,and then estimated the percentage content of eachcomponent relative to the total content of a givensample.

We collected 2 soil samples from locations wherebear geophagy was observed in association with fishconsumption: one from near DvukhyurtochnoyeLake in the Ust-Kamchatsky District of Kamchatka(Oct 2004), and the other from the Vengeri Riverbasin in the Smirnykhovsky District of Sakhalin(Aug 2012). There was clear and repeated evidenceof bears consuming soils at both locations.

The mineral and chemical compositions of collectedsamples were examined at the Far Eastern GeologicalInstitute of the Russian Academy of Sciences, FarEastern Branch in Vladivostok, by A.A. Karabtsov.Mineralogical analyses were conducted using mono-chromated Cu radiation using a diffractometer (Mini-Flex; Rigaku Corp., Tokyo, Japan). Samples were air-dried and then saturated with ethylene glycol and cal-cined at 550uC.

Under direction of N.V. Zarubina, the chemicalcomposition of samples was assessed using the atomicemission spectrometry method with an iCAP6500Duo device (Thermo Electron Corporation,Madison, Wisconsin, USA). The microelements com-position was examined via inductively coupledplasma mass spectrometry using an Agilent 7500device (Agilent Technologies, Inc., Alpharetta, Geor-gia, USA). Samples were fused together with lithiummetaborate. The determination of lithium contentwas performed separately following the acid decom-position of the sample (HNO3 + HClO4 + HF).Mineral analyses were performed with scat samplesfrom Sakhalin and Kamchatka, whereas geo-chemi-cal analyses were conducted with scat samples fromSakhalin only (Table 1).

ResultsScat and soil collection by region

We collected most scat samples from Sakhalin.Within the 5-year sampling period (performed annuallyfrom May to Oct), we collected and processed 3,946scats. We extracted samples for analysis from the centerof each scat mass to eliminate the possibility of samplecontamination (from other matter inadvertently cling-ing to the sample). Soils were found in 5.2% of samples(n 5 207). Fish remains were found in 31.7% of

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samples (n 5 1,252). Of the scats that contained soils,87% also contained fish (n5 180). When soils were dis-covered in scats, their mass comprised 5–90% of totalscat mass. The maximum occurrence of mineral soils

in scats was observed in the month of September(12.5%), while the minimum was found in the monthofMay (4.6%; Fig. 2). Based on our visual observations,Pacific salmon (Oncorhynchus spp.) predominated in

Fig. 1. Russian Far East showing locations (Primorsky Krai, Sakhalin, Kamchatka) where brown bear scatsand soil samples were collected during 1999–2013 for this study of geophagy in this species.

Table 1. Samples of brown bear scats, soils, and the types of analyses conducted, where Y 5 collected and N5Not collected, in Russia. Scats were collected from 1999 to 2003 in Primorsky Krai, during 2004 in Kamchatka,and from 2009 to 2013 in Sakhalin. Soils were collected October 2004 (Kamchatka) and August 2012 (Sakhalin).Neither mineral nor geochemical analysis were conducted from Primorsky Krai because no soil samples werecollected there, and no geo-chemical analysis was conducted on the Kamchatka sample because the samplewas collected before such analyses were available in the region.

Location Scat sample Soil sample Mineral analysis Geo-chemical analysis

Primorsky Krai Y N N NSakhalin Y Y Y YKamchatka Y Y Y N

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brown bear diets during the period when they mostactively consumed mineral soils (Aug–Oct).

We collected a single sample of ingested soil onSakhalin, from a hole dug by bears in a spruce–fir(Picea–Abies spp.) forest on the river terrace abovethe Vengari River (a salmon-spawning river),approximately 2 km from the coast. Visually, thesample consisted of a light-colored, clay-like, waterysubstance. The hole itself (50 cm deep and approx.45 cm in diam) was probably excavated $1 year pre-vious, for the purpose of feeding on a mineral sub-stance, and the bottom of this depression had freshbear claw marks.

On Kamchatka, we collected and processed 333brown bear scats from a single season (May–Sep2004), with mineral soils detected in 1% of samples(n 5 4). Three of these were found in September,and one in August. One frozen scat from a bear inKamchatka was almost entirely composed of a claysubstance (Fig. 3). The relatively low proportion offecal samples containing soils from the Kamchatkacollection site as opposed to Sakhalin can beexplained by the greater diversity of food options(berries, herbaceous plants, and less salmon) onKamchatka during the observation period.

We also collected a single sample of soil from aKamchatka location where a bear had ingested a

white, clay-like substance with a bluish tint. In its out-ward appearance, the material was quite similar tothe Sakhalin sample. In order to reach this soil to con-sume it, the bear had to dig a small hole (50 cm deepand 40 cm in diam; Fig. 4). The hole was excavated ata distance of approximately 20 m from a thermalspring on the river terrace of the DvukhyurtochnayaRiver (a tributary of the Kamchatka River and a

Fig. 2. The percentage of brown bear scats containing soils and fish remains in the Vostochny Reserve,Sakhalin Oblast, Russia, by month, during a study of geophagy in this species. Data are combined for years2009–2013. Numbers displayed above data points represent the sample count with either soil or fish remains,while numbers displayed under months show total sample sizes collected that month. Of the total scats thatcontained soils (n 5 207), 87% also contained fish (n 5 180).

Fig. 3. A frozen scat of a brown bear with a largeproportion of a clay-like substance, found in theDvukhyurtochnoye Lake basin (Kamchatka Riverbasin), Kamchatka, Russia, October 2004.

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location where salmon spawn), approximately 1 kmfrom Dvukhyurtochnoye Lake. The upper surfacesoil consists of brownish-black, clay-like substances.The terrace formed from tephrogenous alluvialdeposits owing to its proximity to active volca‐nism. Both the floodplain and the river terraceare densely covered with grass (Gramineae) andsedges (Carex spp.), with occasional dense stands ofwillow (Salix spp.) bushes, and interspersed withdwarf Siberian pine (Pinus pumila) and alder (Alnusviridis fruticosa).

In both cases of soils onKamchatka and on Sakhalin,bears purposefully tried to reach the illuviated soil hori-zon containing white clay, which allows us to supposethat clays with reduced levels of iron (hence, their lightcolor) aremorepreferable to bears than clays containingferric ions. The soils used in the analysis were sampleddirectly from where the bears had consumed them.

From April to November (annually, 1999–2002),we collected 340 brown bear fecal samples in Pri-morsky Krai. Soil substances were discovered in2.9% of those samples (n 5 10). The following, addi-tional materials were also discovered in fecal samplesthat contained mineral soils: grass (n 5 4), mammalmeat (n 5 3), ants (Formica, Myrmica, Camponotus,Lasius spp.; n 5 2), Korean pine (Pinus koraiensis)nuts (n5 1), andMongolian oak (Quercus mongolica)acorns (n5 1). In 3 samples, woody material was alsodiscovered in addition to mineral soils. In PrimorskyKrai, salmon are not as abundant as they are inSakhalin, and the dominant component of bear dietis vegetation—herbaceous plants in summer and Ko‐rean pine nuts and Mongolian oak acorns in autumn.

We note that the consistency of bear fecal samplescollected during the period when the bears eat salmonon Sakhalin and Kamchatka was largely formless andalmost liquid. The presence of soils in the samplesmade them a little firmer. We observed similarly loosescats among bears in Primorsky Krai as they transi-tioned from plant- to meat-based diets.

Mineral and chemical analysis of soilsWe conducted a mineral analysis of both soil sam-

ples (from Sakhalin and Kamchatka). The Kamchatkasample consumed by bears consisted of devitrified,semi-transparent, amorphous, volcanic glass, withtraces of mixed-layer alumosilicates and cristobalite.The Sakhalin sample consisted of clay-like minerals(chlorite [clinochlore] with an admixture of smectites)along with crystals of quartz, micas, and feldspars.

We only conducted a geo-chemical analysis of onesample (from Sakhalin) because this type of analysiswas not available to us in 2004 (when the Kamchatkasample was collected). Based on its chemical compo-sition (Table 2) and microelement composition (Table3), the Sakhalin sample consisted of felsic from theweathering zone. The clay was likely formed by thedegradation of rock by mildly aggressive, soluble sul-fate in the ground water.

DiscussionVertebrates purposely consume soils for a variety

of reasons, including to bolster nutrients lacking in adiet (Worker et al. 2015), to adsorb consumed toxins(Houston et al. 2001), to make a digestive tract lesshospitable to parasites (Hui 2004), to regulate pH of

Fig. 4. A depression approximately 50 cm deep,excavated by brown bears near DvukhyurtochnoyeLake not far from thermal vents in the KamchatkaRiver basin, Kamchatka, Russia, October 2004.

Table 2. Chemical composition of soils consumed bybrown bears in the Vengeri River basin of SakhalinIsland, Russia (showing compound and % of total),from scat samples collected from 2009 to 2013 andfrom soils collected during August 2012.

Chemical compound % of total

Silicon dioxide (SiO2) 66.31%Aluminum oxide (Al2O3) 14.75%Ferric oxide (Fe2O3) 3.73%Potassium oxide (K2O) 2.09%Sodium oxide (Na2O) 1.45%Magnesium oxide (MgO) 1.12%Iron oxide (FeO) 0.95%Titanium dioxide (TiO2) 0.76%Calcium oxide (CaO) 0.20%Phosphorus pentoxide (P2O5) 0.09%Manganese(II) oxide (MnO) 0.03%Loss on ignition 6.31%

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the gut (Krishnamani and Mahaney 2000), and toreduce physiological stress that results in diarrhea(Shaposhnikov 1953, Panichev 1990).

With respect to brown bears in the Russian FarEast, we observed geophagy in locations where bearsfed on fish, and particularly at the precise times ofyear when fish were intensively consumed by bears.In fact, the occurrence of mineral soils found in bearscats on Sakhalin coincided with the maximum pro-portion of fish remains in those samples as well(Fig. 2). Although our visual observations of bearsfeeding on salmon, other foods, and soils were oppor-tunistic (i.e., not based upon experimental design),our data suggest that in the intervals between feedingon salmon, bears periodically ingest soils. In our 463hours of observations of bears near rivers and/or feed-ing on salmon, we recorded approximately 10 directobservations of geophagy. We did not observe geo-phagic behavior of bears in .100 hours of observa-tions at times when they were feeding on other typesof food.

As compared with Sakhalin and Kamchatka, soilswere ingested far less frequently in Primorsky Krai.This is because salmon are less important in bear dietsthere. In Primorsky Krai, soils are purposefullyingested after a bear eats large quantities of mammalmeat or accidentally while digging up animal dens,insect nests, or feeding on plant roots, tubers, or bulbs

(Seryodkin 2012). Consequently, the proportion ofsoils in bear fecal samples in Primorsky Krai was low.

Our observations suggest that bears begin to ingestsoil substances at times of the year when there aresharp transitions in their food regimen, such aswhen they shift from a plant-based diet to a fish-based diet. We observed that bears often sufferedfrom digestive distress accompanied with bouts ofdiarrhea during periods of fish- or meat-predominantconsumption. In the case of brown bears, it seemsthat the ingestion of mineral soils may, in such cases,prevent the onset of diarrhea or shorten the durationof the affliction should it have already developed.This conclusion was also reached by Mattson et al.(1999) in their study of brown bears in North Amer-ica. The ability of smectite- or kaolinite-based clayminerals to curb diarrhea is widely known (Carretero2002, Dupont and Vernisse 2009, Williams and Hay-del 2010). As a result of these properties, such miner-als have been utilized in traditional medicine andhave been recently used extensively in modern medi-cal practice as well.

The anti-diarrheal properties of clay minerals areutilized to mitigate adsorption of microbiotaimported from the environment and an overabun-dance of various macronutrients (particularly potas-sium), which can enter a bear’s digestive tract inexcessive amounts via consumption of vegetationmatter, especially in spring. An excess of potassiumin the digestive tract can cause a sharp increase inthe amount of water in the digestive tract and resultin diarrhea. It is possible that the observed Septembermaximum of geophagy in bears is a consequence ofsuch excesses of potassium derived from vegetationmatter. However, it is more likely that the high inci-dence of geophagy observed in September is a conse-quence of consuming large amounts of salmon. Theneed of bears to consume clay-containing soils duringthe period of mass eating of fish can be related toboth the disturbance of gut microbiota and the needto excrete excessive phosphorus from the body. Phos-phorus content in fish is significantly greater than themeat of terrestrial mammals, especially in fish bonesand cartilage. Excessive levels of phosphorus in adiet are known to catalyze serious disruptions to abody’s metabolism, including those that result indiarrhea (Ermakov and Tyutikov 2008).

According to the results of our mineralogical tests,the soils ingested by bears can include both clayminerals and the devitrified, amorphous, volcanicglass. It is possible that this latter substance, when

Table 3. Microelement composition (mcg/g) of clay-like soils consumed by brown bears in the VengeriRiver basin of Sakhalin Island, Russia, from scat sam-ples collected from 2009 to 2013 and from soils col-lected during August 2012.

Microelement mcg/g

Barium (Ba) 488.0Zirconium (Zr) 212.3Vanadium (V) 101.4Strontium (Sr) 90.6Rubidium (Rb) 85.6Zinc (Zn) 68.1Chromium (Cr) 60.3Cerium (Ce) 58.7Lithium (Li) 47.2Lanthanum (La) 27.0Nickel (Ni) 24.2Lead (Pb) 23.6Yttrium (Y) 17.6Copper (Cu) 14.0Scandium (Sc) 12.2Cobalt (Co) 9.1Caesium (Cs) 3.9Europium (Eu) 0.7Molybdenum(Mo) 0.6Cadmium (Cd) 0.2

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entering a digestive tract, produces effects similar tothose produced by clay minerals. However, to eluci-date specifically which microelements are beingselected for by bears when they engage in geophagy,additional research (including geo-biological andmicrobiological studies in a controlled environment)should be conducted.

AcknowledgmentsThe authors gratefully acknowledge V. Zhakov, M.

Borisov, J. Paczkowski, and D. Lisitsyn for their assis-tance in collecting field data; as well as employees ofthe Sikhote–Alin Biosphere Reserve, Kronotsky Na‐ture Reserve, Wildlife Conservation Society, andSakhalin Environment Watch for their kind assistance.We also thank Editor J. Belant, Associate Editor M.Fitz-Earle, and reviewers who devoted their time tovastly improve the quality of this text.

Literature citedAGENE, I., U. LAR, S. MOHAMMED, E. GAJERE, B. DANG, D.

JEB, AND J. OGUNMOLA. 2014. The effects of geophagy onpregnant women in Nigeria. American Journal ofHuman Ecology 3:1–9.

CARRETERO, M.I. 2002. Clay minerals and their beneficialeffects upon human health: A review. Applied ClayScience 21:155–163.

DIXON, J.S. 1959. Some biochemical aspects of deer licks.Journal of Mammalogy 20:109.

DUPONT, C., AND B. VERNISSE. 2009. Anti-diarrheal effectsof diosmectite in the treatment of acute diarrhea in chil-dren: A review. Pediatric Drugs 11:89–99.

ERMAKOV, V.V., AND S.F. TYUTIKOV. 2008. Geochemical ecol-ogy of animals. Nauka, Moscow, Russia. [In Russian.]

GILARDI, J.D., S.S. DUFFEY, C.A. MUNN, AND L.A. TELL.1999. Biochemical functions of geophagy in parrots:Detoxification of dietary toxins and cytoprotectiveeffects. Journal of Chemical Ecology 25:897–922.

GORDIENKO, V.N., AND T.A. GORDIENKO. 2005. Brown bearof Kamchatka—A brief practical guide on ecology andconflict prevention. Kamchatpress, Petropavlovsk–Kamchatsky, Russia. [In Russian.]

HOUSTON, D.C., J.D. GILARDI, AND A.J. HALL. 2001. Soilconsumption by elephants might help to minimize thetoxic effects of plant secondary compounds in forestbrowse. Mammal Review 31:249–254.

HUI, C.A. 2004. Geophagy and potential contaminantexposure for terrestrial vertebrates. Reviews ofEnvironmental Contamination and Toxicology 183:115–134.

KRISHNAMANI, R., AND W.C. MAHANEY. 2000. Geophagyamong primates: Adaptive significance and ecologicalconsequences. Animal Behaviour 59:899–915.

MATTSON, D.J., G.I. GREEN, AND R. SWALLEY. 1999. Ge‐ophagy by Yellowstone grizzly bears. Ursus 11:109–116.

NASIMOVICH, A.A. 1938. On learning the mineral nutritionof wild animals in the Caucasian Reserve. Proceedingsof the Caucasian Reserve 1:103–150. [In Russian.]

NIKOLAENKO, V.A. 2003. Kamchatka bear. Logata, Mos-cow, Russia. [In Russian.]

PANICHEV, A.M. 1987. Lithophagy in bears. Pages 112–115in B.S. Yudin, editor. Ecology of bears. Nauka, Novosi-birsk, Russia. [In Russian.]

———. 1990. Lithophagy in the life of animal and humanbeing. Nauka, Moscow, Russia. [In Russian.]

———. 2011. Geophagy: Geological, ecological and bio-medical aspects. Nauka, Moscow, Russia. [In Russian.]

———, K.S. GOLOKHVAST, A.N. GULKOV, AND I.Y. CHEK-

RYZHOV. 2013. Geophagy in animals and geology ofkudurs (mineral licks): A review of Russian publications.Environmental Geochemistry and Health 35:133–152.

SERYODKIN, I.V. 2012. Dietary intake of brown bears in theSikhote–Alin. Achievements in the Life Sciences 4:29–40. [In Russian.]

SHAPOSHNIKOV, F.D., 1953. About “solonization” of wildungulates in the Altai Mountain taiga. Bulletin of Mos-cow Society of Naturalists, Biological Series 1:3–10. [InRussian.]

SLAMOVA, R., M. TRCKOVA, H. VONDRUSKOVA, Z. ZRALY,AND I. PAVLIK. 2011. Clay minerals in animal nutrition.Applied Clay Science 51:395–398.

SOKOL, O.M. 1971. Lithophagy and geophagy in reptiles.Journal of Herpetology 5:69–71.

WILLIAMS, L.B., AND S.E. HAYDEL. 2010. Evaluation of themedicinal use of clay minerals as antibacterial agents.International Geology Review 52:745–770.

WORKER, S.B., K. KIELLAND, AND P.S. BARBOZA. 2015.Effects of geophagy on food intake, body mass, andnutrient dynamics of snowshoe hares (Lepus ameri-canus). Canadian Journal of Zoology 93:323–329. Doi:10.1139/cjz-2014-0237.

Received: 28 April 2015Accepted: 24 April 2016Associate Editor: Fitz-Earle

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