Deficiency of Rare-Earth Elements in Natural Landscape Components as a Cause of Geophagy among Ungulates on Olkhon Island

摘要

The relevance of this research is based on systematic study of the causes of geophagy from the viewpoint of the rare-earth hypothesis. It follows from the original results of comprehensive geological-hydro-biogeochemical studies carried out on Olkhon Island (Lake Baikal) that the phenomenon of geophagy in wild and domestic ungulates is due to a deficiency of light rare-earth elements (LREEs) in plant foods and natural waters. This deficiency is related to a low LREE concentration in the composition of the most common met-amorphic terrigenous-carbonate rocks, talus, and soils in the island. This geochemical specificity of landscapes can be the cause of LREE imbalance in the hormonal system of the body. The hormonal stress makes animals consume regularly and periodically kaolinite clays of weathering rocks enriched in the necessary elements.