This BBC report calls into question declaring polar bears endangered.

"We have this specimen that confirms the polar bear was a morphologically distinct species at least 100,000 years ago, and this basically means that the polar bear has already survived one interglacial period," explained Professor Ingolfsson.

"And what's interesting about that is that the Eeemian - the last interglacial - was much warmer than the Holocene (the present).

"This is telling us that despite the ongoing warming in the Arctic today, maybe we don't have to be quite so worried about the polar bear. That would be very encouraging."