Bones and fossils found in caves show that polar bears once roamed the Scottish Highlands. Initially thought to belong to brown bears, new analysis of the bones and teeth prove they actually belonged to their arctic cousins.
Bears are not often associated with Britain, but they were once common here. They went extinct around 1,000 years ago. The University of Aberdeen and National Museums Scotland have been reviewing the ancestry of bears in Scotland. When they re-studied a fossil collection from the Inchnadamph Bone Caves, they discovered that the bears that stalked across the Highlands 30,000 to 50,000 years ago had a heavy seafood diet. This differed considerably from the diet of modern brown bears, which feed on meat and plants, and of other ancient bears in Britain.
From this, they concluded that polar bears lived in Scotland during the last Ice Age.
“These bears appear to have lived almost exclusively on seafood,” said study co-author Kate Britton. “Even modern grizzly bears, known to gorge seasonally on salmon in some places, don’t show anything close to this level of seafood consumption in their diet.”
The huge disparity in diet means one of two things. Either brown bears ate differently in the past, or the bones and teeth belong to a different species of bear.
Polar bears can both hitch a ride on drifting ice floes and swim comfortably in icy water. Photo: Jerry Kobalenko
Great swimmers
The idea that they might belong to a polar bear is not that far-fetched, considering the climate at the time. During the last Ice Age, sea ice in the Atlantic Ocean would have stretched into more southerly waters. Polar bears are excellent swimmers. Even today, individuals have been spotted more than 300km away from land. To reach Scotland is far from impossible. Even Greenland Inuit in their kayaks found their way to Scotland on at least one occasion.
So far, this is the only evidence that polar bears once roamed the UK. But if Ursus maritimus was here, it would likely have encountered ancient brown bears.
The next step is to look for crossovers in DNA. Currently, the team is analyzing modern polar bears for brown bear DNA and examining the remains of Ice Age brown bears for polar bear DNA.
“We know that polar bears and brown bears can successfully interbreed today where their ranges overlap,” said co-author Andrew Kitchener.
