Polar Bears, Brown Bears Interbreed to Cope With Climate Change
Polar bears’ past may echo their future, indicates a genetic study that finds the white-furred, sea ice-dwelling bears interbred with brown bears long after the two species separated as much as 5 million years ago. Climate change likely drove this mixing among bears, writes the research team, noting there is evidence this is happening again.
The study estimates polar bears split from brown bears between 4 million and 5 million years ago, after which they endured fluctuations in climate, including ice ages and warmer times. Polar bears are currently facing the effects of climate change, this time caused by humans, as the Arctic sea ice upon which they live recedes to unprecedented levels.