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The brown bear is one of the largest terrestrial carnivores alive today, with a broad distribution throughout the Northern Hemisphere. In contrast to numerous other large carnivores that faced extinction by the end of the last Ice Age (cave bear, sabretoothed cats, cave hyena), the brown bear is one of the lucky survivors that made it through to the present. The question has puzzled biologists for close to a century – how was this so?
Brown bears are ecologically flexible and have a broad dietary range. While they are carnivores, their diets can also consist primarily of plant matter making them adaptable to environmental changes. However, brown bears also experienced extensive range reductions and regional extinctions during the last Ice Age. Brown bears used to occupy a much wider range including Ireland, Honshu, the largest island of Japan, and Quebec (Canada).
Did the decline or disappearance of bear populations in certain areas happen because bears left those places for better ones that they still currently live, or did unique groups of bears with distinct genes inhabit those areas and go extinct, leading to a loss in the overall diversity of the DOI: 10.1098/rspb.2023.2411