New neighbor.

Move over polar bears. An oddball grizzly has invaded its northern cousins' high-Arctic neighborhood. Scientists believe no other grizzly has ever been spotted so far north.

Last summer, geologists from the University of Alberta trekked to Canada's remote Melville Island to study its landforms. A whopping 966 kilometers (600 miles) north of the Arctic Circle, the island is outside grizzlies' traditional range on the North American mainland. So the scientists were shocked to find strange-looking paw prints near their research cabin. "The tracks show claws that are about 10 centimeters (3 inches) long," explains Jonathan Doupe, one of the geologists. "These giant claws are a characteristic of grizzlies." Polar bears, thought to be the island's sole bear species, have shorter claws.

Baffled, the scientists searched for more grizzly clues. They found brown-colored hair stuck to the cabin. Laboratory analysis of the fur confirms that the DNA, or chemical that carries hereditary information, matches that of a grizzly.

What was a grizzly doing deep in polar-bear country? With limited evidence, Doupe isn't sure. Some scientists speculate that global warming, or the average increase in the temperature of Earth's atmosphere, is thawing the icy Arctic. With the warmer environment, grizzlies may be expanding into newly suitable living spaces up north.