Our studies of the relationship between prehistoric humans and their environment included the taphocenotic analysis of large mammal faunas from key Paleolithic sites in the upper Anui River basin, northwestern Altai. Faunal assemblages from the Denisova, Kaminnaya, and Okladnikov caves and the Ust-Karakol open-air site were examined. Their stratigraphic sequences span a wide chronological interval from 300 to 10 ka BP. To assess the structure of animal resources available to prehistoric humans, quantitative ratios of 17 taxa or groups of taxa were analyzed, representing carnivores (Carnivora), proboscideans (Proboscidea), odd-toed ungulates (Perissodactyla), and artiodactyls (Artiodactyla). The distribution of bones of large herbivorous mammals suggests that the primary bioresources for the earliest humans in the Anui basin were Siberian ibex, argali, bison, and horses. Other preferably hunted mammals were antelopes (dzeren and saiga), as well as deer (red and roe deer). Woolly rhinoceros was hunted less frequently. The main competitors of Paleolithic humans in consuming animal bioresources were large predators (hyena and wolf), and the main rivals in cave shelters were bears and hyenas.