Aquafacts / Steller Sea Lions

Steller sea lions 

Read some of the most frequently asked questions we’ve received about steller sea lions, answered by our biologists and other reputable sources/

Quick info

70%

Of population lives in Alaska

6%

Percentage of body weight eaten per day

1 to 3 years

Typical nursing time for a pup

424 metres

Deepest dive recorded

What are the differences between Steller sea lions and harbour seals?

Steller sea lions are larger and have longer flippers. They are very vocal and can be aggressive while defending their territory. Sea lions are also able to support themselves on their front two flippers and can pull their hind flippers under their bodies to walk. Sea lions swim with their front flippers, while seals swim with their hind flippers. Seals have a smaller and sleeker torpedo shaped body, rarely vocalize and tend to be quite shy. Seals do not use their flippers to support their bodies on land and move by sliding or shuffling.

Where do steller sea lions live?

Steller sea lions range throughout the Pacific Rim (from northern California to Northern Honshu in Japan, and to the Bering Strait). About 70 percent of the Steller sea lion population resides in Alaska. Steller sea lions are highly gregarious and they use traditional haul out sites (an area used for resting) and rookeries (an area used for breeding and rearing young) on remote and exposed islands. These sites can be rock shelves, ledges, boulders, and gravel or sand beaches.

What do steller sea lions eat?

Adult Steller sea lions eat a wide variety of fishes, including Pacific herring, pollock, salmon, cod, and rockfishes. They also eat octopus and some squids. On average, an adult Steller sea lion eats about six percent of its body weight each day.

How do steller sea lions reproduce?

Steller sea lions mate and give birth on land. Births occur mid-May to mid-July and peak in June. In May, dominant males (nine years and older) establish their breeding territories on rookeries, and maintain them for approximately 40 days without eating. During this time, the males establish a group of females (harem) and mate with many females on their territories, demonstrating their polygamous nature. Mating occurs soon after the birth of the previous year's pups. The pups are fed on their mother's milk, and they enter the water at four to six weeks of age. Some pups will nurse for 1 to 3 years, but most are believed to wean before they are 1 year of age. Females give birth to one pup only, and may not give birth every year. Pups are able to crawl and swim soon after birth. Females accept only their pups, recognizing their pup's vocal and olfactory cues. Pups will approach other females, but are often bitten or thrown by females who have their own pups. Males defend territories for an average of 2 years. Pups are sometimes killed or injured from: a storm washing them away from a rookery; by adults tossing, biting, or crushing them; or by abandonment and disease.

Our experts are doing important research in the field and on site at the Vancouver Aquarium. Learn more about ocean research.