New light on polar bears

Polar bears are five times older than previously thought and adapted slowly to Arctic conditions during the last Ice Age, research suggests.

New genetic evidence underlines the threat posed to the iconic animals by human activity and global warming.

Scientists writing in the journal Science now believe polar bears date back some 600,000 years – during one of the Earth’s coldest periods – and evolved gradually over a series of repeated glacial cycles.

The pressure on polar bears would be amplified by human factors such as habitat loss, hunting and pollution, the experts fear.

Earlier research suggested polar bears were much younger, and essentially were a recently evolved type of northern brown bear.