Collagen Contents of 13 С and 15 N Isotopes in Bones of Small Cave Bear Ursus (Spelaearctos) rossicus Borissiak, 1930 (Mammalia, Carnivora, Ursidae) from Western Siberia.

The 13 C and 15 N isotope contents in collagen were determined in bones of the small cave bear Ursus (Spelaearctos) rossicus Borissiak, 1930 from three regions of Western Siberia. The bones dated back to marine isotope stage (MIS) 3 and belonged to mature males and females. Some of the samples differed only in δ15 N. Bears of all samples were from the same trophic level. Trophic shifts were observed between females and males in one region and between males of two regions. The small cave bear of Western Siberia differed from the small cave bear of the Southern Urals in leading a much more predatory lifestyle. The extent of differences between the Ural and Siberian bears corresponded to different trophic levels.