Polar bears have evolved to survive in the Arctic with large, oar-like front paws for better swimming, as well as insulating blubber, and two layers of fur for the frigid temperatures. They rely on pack ice, traveling thousands of miles in a year looking for food (mostly ringed and bearded seals, although they hunt other animals if they come across them). Polar bears are listed as threatened by the U.S. Endangered Species Act and vulnerable by the IUCN Red List.