Steller's Sea Lion
Steller's sea lions belong to the
Mammalian Order Pinnipedia, in the family Otariidae. Other members
of Otariidae include all species of fur seals and sea lions.
Otariids are easily distinguishable from other pinnipeds by their
external ear flaps. Steller's sea lion's scientific name is
Eumetopias jubatus, which means "having a mane and large
forehead". This animal is named for George Wilhelm Steller
(1709-1746), a German zoologist who explored the coastal areas of
the northern Pacific Ocean in 1740.
Steller's sea lion is one of the
heaviest pinnipeds, outsized only by elephant seals and walruses.
Males may grow 10-13ft in length and 1800-2000 lbs in weight.
Females grow to about 8ft and 600 lbs. The average life span is
about 20 years. At first glance, Steller's sea lions appear very
similar to California sea lions. However, differences do exist.
Their fur is a lighter color than the California sea lion, light
tawny brown. Steller sea lion males do not have a saggital crest on
their forehead and they have a blunter nose than California sea lion
males. The vocalizations of each species are also different.
California sea lions produce a honking bark, while Steller's sea
lions release a deeper growl. Like all sea lions, mature males have
a mane, their large necks and shoulders covered with long hair.
Steller's sea lions are found in the
Bering Sea surrounding the Aleutian Islands, throughout the Asian
coast to northern Japan and down the American coast to southern
California. Steller's sea lions eat squid, octopus, salmon, other
fish, and fur seal pups.
Males establish harems during the
breeding season. These harems include 10-15 females located on a
territory under control by the male. The male will defend his
territory and harem for two months, and during these two months he
will not eat. Females give birth around June or July. They breed
again very soon after birth. Delayed implantation of the fertilized
egg prevents the pup from being born until the next birthing
season. Weaning age varies but is generally one year.
The population of Steller's sea lions in
Alaska has declined 50% from the 1970's to the 1980's. This species
was considered threatened in the 1990's, and is now considered
endangered. Although the California sea lion is thriving, the
Steller's sea lion's numbers are steadily falling. Suspected causes
for their decline include overfishing and pollution. However, it is
still odd that the California sea lion is thriving while Steller's
sea lion is declining.