High-resolution techniques reveal the palaeoecology of an exceptionally large Ursus arctos from the Late Pleistocene of East Siberia

Cementum and dentin increment analysis and dental microwear analysis were used for the first time to study the dental remains of a giant brown bear (Ursus arctos) from the Late Pleistocene of Yakutia, Russia. Dental increment analysis showed that this bear died during the warm season (May–Sep) in the prime of its life—at the age of 15+ years. Dental microwear analysis inferred that this bear had a varied diet consisting of a wide range of plant items, varying from soft-mast during warm season to hard-mast during hyperphagia period, but with regular intake of animal protein throughout the year. Diet in the last few weeks before death was inferred as mainly herbivorous and mainly comprising soft-mast abrasive grasses. Data on vegetation and climate in the territory of Yakutia during the Late Pleistocene, and comparisons with the dietary habits of extant U. arctos from Yakutia, allowed us to narrow the period of death of the animal within the warm season. The exceptionally large size of the bear combined with its omnivorous diet may indicate favorable living conditions for brown bears in the Mammoth steppe of Yakutia.