IIIIIII knew it!
Polar bears are icons of the Arctic, symbolizing the region’s stark beauty as well as its swift decline due toglobal warming. But according to a new study published in the journal Current Biology, all polar bears alive today descend from a single female brown bear that lived 20,000 to 50,000 years ago in what’s now Ireland. DNA samples from all corners of polar bear country reveal that every individual can be traced back to this single Irish ancestor, the AFP reports.In addition to finding polar bears’ Irish roots, the study also shows they periodically interbred with brown bears over the past 100,000 years. Grizzly bears are now migrating north into polar bears’ habitats as global temperatures rise, a trend some experts have worried could further threaten the already-endangered Arctic bears — but in light of the two species’ history together, that interbreeding may not be such a bad thing, the study’s authors suggest. “Hybridization could certainly result in the loss of unique genetic sequences, which could push them toward extinction,” says lead author Beth Shapiro, a professor at Pennsylvania State University. “But scientists should reconsider conservation efforts focused not just on polar bears but also on hybrids, since hybrids may play an underappreciated role in the survival of certain species.”
It has long been known that polar bears descended from ancient brown bears, but the new study shows that polar bears have plenty of evolutionary experience in adapting to changing circumstances — suggesting their romantic past with grizzlies could help them endure the upheavals of climate change. “Generally, this [interbreeding] seems to happen when climate changes force the bears to move into each others’ habitat,” Shapiro says. “When they come into contact, there seems to be little barrier to them mating.”
(Sources: Agence France-Presse, London Independent)
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