Polar bears are classified as marine mammals because they spend most of their lives on the sea ice of the Arctic Ocean. They have a thick layer of body fat and a water-repellant coat that insulates them from the cold air and water. Considered talented swimmers, they can sustain a pace of six miles per hour by paddling with their front paws and holding their hind legs flat like a rudder.
Polar bears spend over 50 percent of their time hunting for food, but less than two percent of their hunts are successful. Their diet mainly consists of ringed and bearded seals because they need large amounts of fat to survive.
The total polar bear population is divided into 19 units or subpopulations. Of those, the latest data from the IUCN Polar Bear Specialist Group show that 8 subpopulations are in decline and there is a high estimated risk of future decline due to climate change.
Because of ongoing and potential loss of their sea ice habitat resulting from climate change, polar bears were listed as a threatened species in the U.S., across their range, under the Endangered Species Act in May 2008.