The Khayrgas Cave in Yakutia (eastern Siberia) is one of the most important Upper Paleolithic sites in northern Asia, and has been the subject of extensive 14C dating and study of mammal bones. The upper part of the cave sequence (Layers 2–4) dates to the Holocene (~4100–8200 BP), and the lower part (Layers 5–7) to the Late Pleistocene (~13,100–21,500 BP). In Layers 2–4, only extant animal species are known; ecologically they belong to a forest-type ecosystem. In Layers 5–7, several extinct species were identified, and the environment at that time corresponded to open and semi-open ecosystems. The Khayrgas Cave provides rare but reliable evidence of human occupation in the deep continental region of eastern Siberia at the Last Glacial Maximum, ~20,700–21,500 BP.