More than 90 percent of the world's sea otters live in the coastal waters of Alaska from Prince William Sound to the Aleutian Islands, with numbers estimated at 150,000 to 200,000.
Sea otters are the smallest marine mammals.
Adult males are about 5 feet long and weigh between 60 and 85 pounds. Their small size is a dubious distinction in an environment where sheer bulk is an adaptation against the heat-sapping properties of water. In addition, sea otters do not have the thick, insulating layer of blubber found in cetaceans and pinnipeds. They rely, instead, on their fur and a rapid metabolism to survive in the near-freezing waters of Alaska's seas. The sea otter's dark brown to black fur is the most dense of any marine mammal.