The Steller Sea Lion (Eumetopias jubatus), also known as the Steller's sea lion or northern sea lion, is a species of sea lion from the rocky coasts of the northern Pacific. It is the largest member of the eared seals (sea lions and fur seals). Among pinnipeds, it is inferior in size only to the walrus and the two species of elephant seals. The species is named for the naturalist Georg Wilhelm Steller, who first described them in 1741. The Steller sea lion has attracted considerable attention in recent decades, owing to significant and largely unexplained declines in their numbers over an extensive portion of their northern range in Alaska.
Steller sea lions tend to live in the coastal waters of the subarctic because of the cooler temperate climate of the area. Like all otariids, Steller sea lions are amphibious and spend some time in water and some on land. Typically, Steller sea lions spend their time in the water feeding but haul-out onto land to reproduce, raise their pups, molt, and rest. Steller sea lions usually congregate on isolated islands because they are the ideal terrestrial habitat. These isolated islands are preferred by Steller sea lions because they can avoid predation from terrestrial predators, easily thermoregulate (by means of cooling winds), and access offshore prey more easily. It is a vicious marine predator, hunting animals as large as northern fur seals, harbor seals, and sea otter pups. However, they usually go after fish and cephalopods. Atka mackerel, salmon, halibut, herring, capelin, flatfish, Pacific cod, rockfish, sculpins, sand lance, and cephalopods such as various and .