| Home: Special status species: Steller sea lion: Natural history |
SPECIAL STATUS SPECIES: STELLER SEA LION (Eumetopias jubatus)
NATURAL HISTORY |
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| General |
| Taxonomy: |
Order
Carnivora, Suborder Pinnipedia, Family Otariidae
(sea lions and fur seals). The only species in the
genus Eumetopias. An alternative common
name for this species is the Northern sea lion.
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| Appearance: |
Like all
members of Family Otariidae, this species has external
ear flaps (pinnae), fore-flippers with long digits
used for propulsion under water, and hind-flippers
that rotate forward under the hips allowing the animal
to walk on land. This is the largest of the Otariidae.
Males are longer and significantly heavier than females.
Males can reach 3.25 m (10-11 ft) and 1,120 kg (2,400
lb). Females can reach 2.9 m (9.5 ft) and 350 kg (770
lb).1
Both sexes are covered with reddish-brown to blond
fur and have dark brown flippers. Males have a thick
mane that extends from the back of the head to the
shoulders. Males also have a well-defined forehead.
In both sexes the snout is short, blunt, and broad. |
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| Feeding Behavior |
| Overview: |
This species feeds on a variety
of demersal, semi-demersal and pelagic fishes and
cephalopods. They may venture up large rivers to catch
lamprey and salmon. Some males may kill small marine
mammals. |
| Prey Items: |
Walleye
pollock, Pacific cod, Pacific sand lance, spotted
cusk-eel, Pacific hake, salmon, capelin, mackerel,
rockfish, flatfish, Pacific herring, lamprey, octopus,
squid and occasionally northern fur seal pups, small
harbor and ringed seals, and sea otters.1 |
| Method of
Capture: |
While foraging,
juveniles dive to average depths of 20-40 m (65-130
ft) and an average duration of one minute. Dives can
reach depths of up to 350 m (1,150 ft).9
Adult females in Alaska showed similar patterns.17 |
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| Reproduction |
| Overview: |
Rookeries are located on offshore
islands. Dominant mature males maintain territories
for one to two months and mate with many females.
During the breeding season, males do not eat. Mothers
stay with pups for one to two weeks before hunting
at sea. Then they spend roughly equal amounts of time
hunting and nursing pups on land. |
| Time to Maturity: |
Females: 3-6 years.1
Males: 3-7 years, but 8-10 years to hold a territory.8
|
| Longevity: |
Males can live up to
20 years and females up to 30 years.8
|
| Breeding
Season: |
Pups are
born from mid-May to late-July. Mating occurs 11-14
days after the pups are born.1 |
| Frequency
of Breeding: |
Can give birth annually. |
| Gestation
Period: |
Approximately 50-51
weeks (includes a delayed implantation period of
3-4
months).1 |
| Number of
Offspring per Pregnancy: |
One |
| Parental
Care: |
Maternal; pups usually nurse
for 9-12 months, but some continue to nurse for up
to three years. |
| Mating
System: |
Extremely polygamous;
males hold territories and attempt to mate with all
females in the territory. |
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