New York Times: Polar Bears Did Not Descend From Brown Bears, DNA Study Indicates
Polar bears on pack ice in the Beaufort Sea off northern Alaska. Scientists say polar bears are not descended from brown bears.
Photo Credit: Steve Amstrup
Instead, according to a research team that looked at DNA samples from the two species and from black bears, the brown bear and polar bear ancestral lines have a common ancestor and split about 600,000 years ago.