The ancestry of polar bears just got a lot longer. A new German study concludes that the bears emerged as a separate species in the Arctic about 600,000 years ago, far longer than the earlier estimate of 150,000 years, reports LiveScience. Researchers did extensive DNA research to pinpoint the older date and think they figured out why previous researchers got thrown for a loop.
The short version: Polar bears split from brown bears 600,000 years ago, went about their separate ways, then came into contact with brown bears again during a relatively warm spell about 150,000 years ago. This "hybridization" left its mark in modern bears and led to the faulty estimate. The lead researcher began the project because he reasoned that 150,000 years was nowhere near long enough for polar bears to evolve all their distinctive traits. It would have been "miraculous" if true, he says. (Read more polar bears stories.)