Abstract

Polar bear (Ursus maritimus) is the apex predator of the Arctic, largely dependent on sea-ice. The predicted disappearance of the ice cover of the Arctic seas by the mid 21th century is likely to cause a dramatic decrease in the global range and population size of the polar bear To place this scenario against the backdrop of past distribution changes and their causes, we use a fossil dataset to investigate the polar bear’s past distribution dynamics during the Late-Pleistocene and the Holocene. During the last deglaciation, polar bears were present at the south-western margin of the Scandinavian Ice Sheet, surviving until the earliest Holocene. There are no Arctic polar bear findings from 8,000-6,000 years ago (8-6 ka), the Holocene’s warmest period. However, findings from 8-9 ka and 5-6 ka show that the species was able to survive this period likely in cold refugia in the East Siberian Sea, the northernmost part of Greenland and the Canadian Archipelago. A marked range expansion is observed over the last 4,000 years in tandem with cooling climate and expanding Arctic sea ice. Our results highlight a remarkable dynamism of polar bear’s distribution in response to Late Pleistocene and Holocene Arctic temperature and sea ice trends.