The polar bear has a become an (insufferably cute) symbol of global warming -- meaning we were extra keen on reading into a new study, published in Science, on the genetic origins of these Coke-drinking cuddlers, looking for insight on how climate change will affect them. The answer, it turn out, is mixed.
The study, performed by a group of scientists at the German Biodiversity and Climate Research Centre, cross-examined nuclear DNA from polar bears, brown bears, and black bears. “Polar bears diverged from their closest relatives about 600,000 years ago, according to a new genetic analysis," writes the team. "The findings suggest the cold adapted species is about five times older than previously thought, and may have had more time to adapt to arctic conditions than recently assumed.” Polar bears were once thought to have adapted to the Arctic cold uncharacteristically quickly for mammals; a previous study, pegging the split-off between the brown bear and polar bear more recently, had used a less complete genetic profile of bears, extracting DNA from mitochondria instead of cells' nuclei.