7/8/2011 9:18:58 PM
Polar Bears Have a Touch of the Irish?
To the surprise of scientists, new DNA studies show that all polar bears living today may be able to trace their maternal ancestry back to a female brown bear in Ireland. The data suggests that polar bears may have interbred with brown bears during the last Ice Age in or near the vicinity of Ireland, according to a study published in the journal Current Biology.
Long-time polar bear researcher Steven Amstrup, now chief scientist with Polar Bears International, said the suggestion of hybridization isn't a solution to the polar bear's current problem: loss of their sea ice habitat due to climate change.
If polar bears evolved as biologists now think, Amstrup told Science News, the warmest global mean temperatures they experienced were about 1 degree Celsius warmer than now. Predictions have temperatures exceeding that during the next 50 or 60 years. "Crossbreeding or not," he says, "polar bears will not be able to undo 150,000 years of evolution, or even 20,000, in 50 years."
Photo ©Daniel J. Cox/Natural Exposures.