Excerpts: from the Sunday Times: Polar bear is a ‘new’ species
by Jonathan Leake
Polar bears may have come into existence only 150,000 years ago, when trapped brown bears had to adapt to an ice age
Polar bears may have come into existence only 150,000 years ago, when brown bears were trapped by an ice age and had to adapt quickly to survive, scientists have found.
The suggestion follows the discovery of the jawbone of an animal that died up to 130,000 years ago, making it the oldest polar bear fossil found. The bone has yielded new insights into the origins of Earth’s largest land predator.
One is the possibility that polar bears owe their existence not only to past climate change, including ice ages, but have also survived at least one long period of global warming.
The bone was discovered at Poolepynten on the Arctic island of Svalbard by Professors Olafur Ingolfsson, of the University of Iceland, and Oystein Wiig, of the University of Oslo.
In a paper they said: “Brown bears of the ABC islands may be descendants of ancient ursids [bears] that diverged from other lineages of brown bears and subsequently founded the polar bear lineage.” This view is expected to get support from new research, out this week, based on DNA extracted from the Poolepynten jawbone.
It means polar bears have already survived a global warming that affected the northern hemisphere from 130,000 to 115,000 years ago, when the Greenland ice sheet and the Arctic ice cap were smaller than now. Professor Chris Stringer, of the Natural History Museum in London, an expert in ice ages, said: “Early polar bears would not have had all the specialisations of modern animals and we know nothing about their behaviour.
“Living through a warm period back then does not mean they are resilient to climate change now.”