Stellers are the largest of all sea lions, and range throughout the Pacific Rim from southern California to Japan to the Bering Sea. Most of their population still resides in Alaskan waters, despite an unexplained 80 percent decline in numbers through the 1980s and 1990s. In recent years, though, the population has rebounded from California to Alaska, tripling from its low count of 55,000 individuals in the year 2000.
Steller's sea lions are gregarious animals, returning yearly to traditional haul-out sites for socializing, and to favoured rookeries for breeding and the raising of pups. These sites are typically located on remote, exposed islands with landscapes of rocky shelves, ledges and boulders, gravel or sandy beaches.
Sea lion breeding is one of nature’s great mass spectacles. When these giants thunder ashore, the beach literally disappears beneath their numbers. Young pups are sometimes crushed by the throng, unheeded by powerful males with just one purpose in mind. The dominant males, or bulls, each establish and maintain their own spatial breeding territory within the rookery – for over a month, with no food – and mate with females who choose to enter their terrain. Most can not achieve this until they are nine or ten years of age.
Mating takes place a week or two after the previous year’s pups are born. Most sea lion pups wean before their first birthday, but it’s not uncommon for some to nurse for two or three years. Females begin to reproduce at about five years of age, giving birth to a single pup per pregnancy, and may not breed every year.
Sea lion pups begin to crawl and swim soon after they’re born. Sea lion mothers attend to their offspring, recognizing them by their unique sounds and scents. They will not accept another pup, though, often biting or cuffing them aside if they approach. After nursing their pups for their first week of life, mothers will start to leave the rookery to forage for food, staying away for progressively longer periods of time. Late in the summer both mother and pup leave the rookery for the open seas, where they’ll hunt fish, squid, octopusand, occasionally, smaller seals.