Steller sea lion

Eumetopias jubatus

Steller sea lions live on rocky shores and in coastal waters of the North Pacific Ocean, from Japan's northern Honshu and Hokkaido islands north to Russia's Sea of Okhotsk, east to the Bering Strait and south along the west coast of North America to northern California. They are carnivores.

Did you know?

  • George Wilhelm Steller, this species namesake, was a German naturalist; he lived from 1709 to 1746. The Steller's jay is also named for him.
  • Eumetopias is Greek for "broad forehead" referring the cranial crest on their large head, and jubatus is Latin for "having mane" referring to the thick pelage around the neck of males.

Sea lion lingo

  • Pinniped: sea-dwelling mammals with finlike flippers used to move in the water. Seals and walruses are also pinnipeds. Pinni means "feather", and ped means "foot."
  • Bull: a mature male
  • Cow: a mature female

Sea lion behavior and facts

  • Steller sea lions feed on fish such as pollock, flounder, Pacific cod, salmon, rockfish, herring, and sculpin, and invertebrates such as octopus and squid.
  • They spend much of their time on rocky shores, but will stay in water during bad weather and may dive when approached or threatened.
  • They can dive up to 1,300 feet.
  • They are opportunistic feeders and hunt 10 to 15 miles from shore. They also occasionally swim up rivers; they have found good hunting grounds at Bonneville Dam fish ladders in the Columbia River, 146 miles from the Pacific Ocean.
  • They appear to prefer colder climates and are commonly found in near freezing waters.
  • Steller sea lions exhibit sexual dimorphism (males and females differ in coloration and size). Males are 3 times the size of females, have a thick mane of coarse hair, and are brown above and reddish brown below, with dark brown flippers, necks and forequarters. Females are uniformly brown. Sea lions are mostly cylindrical in shape and males have massive necks and forequarters.
  • Taction (touch): Whiskers in pinnipeds are well developed and very sensitive, therefor it is not surprising that they are commonly used for tactile purposes. Besides using their whiskers for "feeling" objects, researchers also believe they are used to detect vibrations in the water.
  • Sea lion caves: America's largest sea cave is located just north of Florence on the Oregon Coast and is a major rookery for approximately 200 Steller sea lions.

From birth to death

  • Birth interval: 1 to 2 years
  • Breeding season: May to June in Oregon
  • Gestation: 11.5 months
  • At birth: one 35- to 50-pound, 3- to 4-foot-long pup. Sea lions nurse for 8-12 months.
  • Sexual maturity: females 3 to 8 years; males 3 to 7 years, when they begin to maintain a harem and defend their territory
  • Males will fast for 1 to 2 months beginning around May, to establish and defend their breeding grounds.
  • Molting occurs July through November with non-breeding and juvenile animals starting first and adult males molting last in the late fall.
  • Lifespan: 18 years for males; 30 years for females

Vital statistics

  • Weight: males 1,200 to 3,000 pounds; females 600 to 770 pounds
  • Length: males 10 to 12 feet; females 9 feet

Status

USFWS: threatened in Eastern Alaska and Washington, Oregon and California; endangered in Western Alaska.

Population numbers declined by more than 80 percent between 1965 and 1994. Current estimates are approximately 67,000 or fewer in U.S. waters. The population that inhabits areas west of 144°W longitude is on the Endangered Species list as the colony continues to decline.

Steller sea lions, the Oregon Zoo and you

The zoo's sea lion Gus lives in the Steller Cove exhibit. He eats herring, capelin, smelt, salmon, squid and trout. In the wild, sea lions threats include pollution, habitat degradation, illegal hunting, and boat strikes or entanglement in fishing equipment. They are protected under the Marine Mammal Protection Act.