An Unusual Variety of Geophagy: Coal Consumption by Snow Sheep in the Transbaikalia Mountains

Abstract

Several places were discovered in the mountains of the Kodar Ridge in Transbaikalia that are regularly visited by snow sheep (Ovis nivicola) for the purpose of consuming coal (Chepa Formation, Jurassic). It was registered by trap cameras that an adult ram eats from tens to hundreds of grams of coal gruss and dust at one time. The “eatable” coals were studied comprehensively, including their geochemistry. The content and balance of mobile forms of trace elements, including rare earth elements (REEs), were determined. It has been established that the sum of REEs in coal varies from 0.19 to 0.27 kg/t, which is 3.5–4 times higher than the clarke value. Elements of the light subgroup (LREEs) predominate in the REE composition. Monazite, xenotime, and rhabdophane were revealed in the consumed coals by analytical scanning electron microscopy. Acid (HCl, pH-1) extract showed that among the elements released from the coal, only a few trace elements, including LREEs, are likely to be significant to the animals. The data that we obtained from the previous landscape-geochemical studies in the areas of mass geophagy in Sikhote-Alin and Gorny Altai and on Olkhon Island (Baikal) suggest that snow sheep on the Kodar Ridge regularly consume coal due to the intention of the animals to restore a disturbed REE balance in the body.