Home Range Polar bears were once thought to be aimless wanderers, continually on the move across the sea ice. Scientists now believe that polar bears, like other members of the bear family, have distinct territories, or home ranges. A polar bear's home range can be enormous, far greater than that of any other species of bear. A single polar bear may rove across an area twice as big as the country of Iceland. One Alaskan polar bear was found to have a home range 45 times the size of Tennessee's Great Smoky Mountains National Park, which supports some 400 black bears.
Scientists note that the size of a bear's range is determined by the amount of available food.
Polar bears living in areas with an abundance of ice and seals have smaller home ranges. A polar bear's home range often overlaps those of other polar bears. This is particularly true in food-rich areas. An area where many home ranges overlap is called a subpopulation. Scientists have identified 12 subpopulations of polar bears in the circumpolar region.