DNA Study Shows Polar Bears Existed for Millions of Years; May Adapt to Climate Change

By Michael Oleaga | First Posted: Jul 24, 2012 05:49 PM EDT

Polar bear cub stands with its mother Venus in their enclosure in Ranua Zoo. (Photo : Reuters)

Polar bear DNA has shown that the arctic bears first emerged four to five million years ago. The discovery comes as a surprise as it was expected polar bears existed somewhere between 60,000 to 600,000 years ago after interacting with brown bears.

The indication that the polar bears lived for such time might prove that they adapted through both cold and warmer eras of time.

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Published in the Proceedings of the National Academy of Science, the researchers from Penn State University and the University of Buffalo, stated the bears' population increased in response to the changing weather over the millions of years, which further indicates how they might respond to climate change today.

"Bears in the past have gone through a lot of extreme changes in climate," said Penn State's biologist Webb Miller. "That's not to say they'll make it through this one."

The researchers used a method of genomic analysis to compare polar bear DNA sequences and compared it to fellow brown and black bears, with the help of a 120,000-year-old polar bear tooth.

Miller added, "The methods we used are quite recently developed. Being able to look at a few complete genome sequences and make inferences about species history, this is a brand-new research area."

Miller was one of the scientists that believed polar bears were only over a hundred-thousand years old, with a calculation that they date back 150,000 years ago.

"Not even close," said Miller upon the new results of the polar bears' DNA. "I expect that polar bears have been white for millions of years."

The theory of their white fur stems from genetic markers that are between four million and five million years old.

The study suggested the polar bear population changes on whether climate change affects the ice used as a hunting platform, notably in the arctic.