Polar Bears are the only bear species to be considered marine mammals. In fact the latin name for Polar Bear, Ursus maritimus, means maritime bear. This is because they depend on the ocean for their food and habitat. They also have many physical characteristics that make them well adapted for life in the cold Arctic Ocean. They are excellent swimmers with streamlined bodies and tiny webs between their forepaws to help propel them through the water. A thick layer of blubber and a water-shedding coat keeps them warm in cold temperatures both in and out of the water.