Stellar's sea lion

Eumetopias jubatus

Description

This is the largest species of sea lion. The Steller’s sea lion has a yellowish buff colored coat of short, coarse fur with no distinct undercoat. There is a sexual dimorphism between the males and females; males are much larger than females in terms of length and weight (males tend to weigh 566kg and females tend to weigh 263kg), males also have very thick, muscular necks with a mane of coarse long fur.

Habitat

The Steller’s sea lion is found on the North Pacific coasts of Russia, Japan, Canada, and part of the United States. This species prefers cold waters. Males of this species are very aggressive and territorial. They will defend their territory and harem by fighting with other males, biting and throwing their bodies against one another.

Feeding Behavior and Diet

This species is carnivorous, feeding on fish and cephalopods (octopus and squid). The walleye Pollack makes up a large part of their diet, but this fish is commercially exploited, causing populations of sSeller’s sea lions to decrease.

Reproduction

Steller sea lions mate in May; males will establish a territory and a harem of 3-20 females. The strongest bull (male) has the largest harem. Twelve months after mating (including a 3 month delayed implantation period) the female gives birth to one pup in late May to early June. The young of the Stellar’s sea lion are called “pups”, these pups are about 100cm long and weigh 16-23kg when they are born. Pups are nursed by their mother for at least 3 months and sometimes even up until the next pup is born a year later. Newborns have thick, dark brown fur that molts into a lighter color after 6 months. When the pups are 2-3 years old their fur changes to the adult color. They can swim after one month and are able to catch food when they are 3 months old.  Females reach sexual maturity at 3-6 years old while the males reach sexual maturity at 3-7 years old. About two thirds of females have young every year and these females are impregnated shortly after giving birth.

Months and Times of Activity

This species does not migrate like some pinnipeds, but they do move seasonally to different feeding and resting areas. The Steller’s sea lion is very difficult to see in the wild because they are skittish, especially in the winter.

Special Features, Stories, Relationships

•    Seals, sea lions and the walrus are pinnipeds, which means “fin footed”.
•    Sea lions and seals are not the same animal. Sea lions have longer skin covered flippers than seals who have short, fur covered flippers with tiny claws at the end of each flipper. Sea lions are noisy creatures while seals are quiet and communicate using grunts. Seals sea lions are capable of rotating their hind flippers forward to use all four limbs on land even in a “walking” motion, while seals are belly crawlers, flopping around on land. Also, sea lions have external ear flaps while seals do not have these ear flaps and instead have two tiny holes on either side of their head.
•    The Steller’s sea lion was placed on the Endangered Species list in 1990 and is currently a threatened species.
•    To read Native American Legends of this animal go to: http://www.firstpeople.us/FP-Html-Legends/TheSeaLionOfSilverIslet-Ojibwa.html
•    Children’s book featuring this animal: Astro The Steller Sea Lion by Jeanne Walker Harvey

References

Keranen, D. 2013. "Eumetopias jubatus" (On-line), Animal Diversity Web. Accessed November 04, 2014 at http://animaldiversity.ummz.umich.edu/accounts/Eumetopias_jubatus/.

NOAA. "Seals and Sea Lions Are Marine Mammals Called 'pinnipeds' That Differ in Physical Characteristics and Adaptations." National Ocean Service. National Oceanic and Atmospheric Administration, 11 Jan. 2013. Web. 14 Feb. 2013.

"Steller Sea Lions: Marine Mammal Research Consortium." North Pacific Universities Marine Mammal Research Consortium. Steller Sea Lion Life Biology, n.d. Web. 14 Feb. 2013.