Diet of the Small Cave Bear Ursus (Spelaearctos) rossicus Borissak, 1930 (Mammalia, Carnivora, Ursidae) As Revealed by C and N Isotope Analyses in Bone Collagen.

The C and N isotope contents in bone collagen were analyzed using bones of the small cave bear Ursus (Spelaearctos) rossicus Borissak, 1930 from localities in the Middle and Southern Urals. The bones date from the last interglacial (MIS 5) and glacial (MIS 3) periods. The bones were from males and females aged 3, 4, and >4 years. Sexual, geographical, and chronological differences in C and N contents were studied. Notable gender, geographic, and chronological differences were observed between samples. In the Middle Urals, females led a more predatory lifestyle than males during the interglacial period, and the trophic niches of males and females converged due to an increase in herbivory during the transition to the glacial period. In the Southern Urals, males led a more predatory lifestyle than in the Middle Urals during the interglacial period. The extent of changes in δC and δN values in the Southern Urals during the transition was found to correspond to differences between trophic levels.