Marine Mammal Laboratory

Harbor seals inhabit coastal and estuarine waters off Baja California, north along the western coasts of the United States, British Columbia, and Southeast Alaska, west through the Gulf of Alaska and Aleutian Islands, and in the Bering Sea north to Cape Newenham and the Pribilof Islands. They haul out on rocks, reefs, beaches, and drifting glacial ice, and feed in marine, estuarine, and occasionally fresh waters. Harbor seals generally are non-migratory, with local movements associated with such factors as tides, weather, season, food availability, and reproduction. However, some long-distance movements of tagged harbor seals have been recorded, mostly among juvenile animals. The harbor seal breeding season follows a cline along the coast of North America, with pups born earlier in the south than in the north; the only exception is harbor seals in the inland waters of Washington which are born 2 months later than seals at the same latitude along the coast. There is little sexual dimorphism in harbor seals; adult males are 1.4 to 1.9 m long and weigh up to 140 kg; females are 1.2 to 1.7 m and weigh up to 80 kg.; pups are 7 to 8 kg at birth.