Paleodiet and niche partitioning among the easternmost European cave bears based on tooth wear analysis

Extinct cave bears inhabited a large part of Eurasia in a wide diversity of habitats during the Pleistocene. This study investigates via tooth wear analysis the feeding habits of 66 individuals belonging to three genetically different species located in the Urals and eastern Europe: Ursus rossicus from Kizel cave, U. kanivetz from Secrets cave, and U. ingressus from Shiriaevo 1 cave. For the microwear analysis, the three species were compared with a reference collection of extant ursids. The dietary space of U. kanivetz does not match any of the extant species' spaces. U. rossicus and U. ingressus tended towards some of the extant species' measurements without any overlapping. For all three sites, the same microwear pattern was identified for all age groups (juvenile, prime, and old adult), meaning no differences related to ontogeny were found. The extinct species presented a larger number of coarse scratches compared to extant species, pointing to a preference for abrasive food items like dry grass or shrubs typical of the mammoth steppe biome during the cold season. These results indicate a niche partitioning between U. rossicus and U. kanivetz that co-existed in the same area, and in this way they avoiding competition.