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NORTHERN ELEPHANT SEAL
Mirounga angustirostris
meaning of Latin name: having a narrower snout than the southern
elephant seal
DESCRIPTION:
Elephant seals are well named because their large noses resemble
an elephant's trunk. Males begin developing this enlarged nose,
or proboscis, at sexual maturity (about three to five years), and
it is fully developed by seven to nine years. Adult males may grow
to over 13 feet (4 m) in length and weigh up to 4,500 pounds (2,000
kg). The females are much smaller at 10 feet (3 m) in length and
1,500 pounds (600 kg). The northern elephant seal is the second
largest seal in the world, after the southern elephant seal.
The elephant seal is in the phocid, or true seal, family. It lacks
external ear flaps and moves on land by flopping on its belly. The
elephant seal has a broad, round face with very large eyes. Pups
are born with a black coat which is molted, or shed, at about the
time of weaning, revealing a sleek, silver-gray coat. Within a year,
the coat will turn silvery brown.
RANGE/HABITAT:
Northern elephant seals are found in the North Pacific, from
Baja California, Mexico to the Gulf of Alaska and Aleutian Islands.
During the breeding season, they live on beaches on offshore islands
and a few remote spots on the mainland. The rest of the year, except
for molting periods, the elephant seal lives well off shore (up
to 5,000 miles, or 8,000 km), commonly descending to over 5,000
feet (1,524 m) below the ocean's surface.
BEHAVIOR:
While living in the open ocean, northern elephant seals spend a
lot of time diving, up to two hours at a time. They rarely spend
more than four minutes at the surface of the water between dives.
It is believed that they eat deep-water, bottom-dwelling marine
animals such as ratfish, swell sharks, spiny dogfish, eels, rockfish,
and squid. Elephant seals molt each year between April and August,
shedding not only their hair but also the upper layer of their skin
as well. This is known as catastrophic molt.
MATING AND BREEDING: Each winter, elephant seals arrive at their
breeding beaches in Mexico and California. Males are the first to
arrive and they fight each other to establish dominance. During
this time, dominant males will often inflate their noses and produce
a noise that sounds like a drum to warn lesser males away. Females
soon arrive, and associate with dominant males. Several days after
coming onto the beaches the females give birth to the pups they
have been carrying since last year. Pups weigh 75 pounds (35 kg)
or more and are about four feet (1.25 m) in length. The pups nurse
for about 28 days, generally gaining about 10 lbs (4.5 kg) a day.
Around the time of weaning, the mother will mate with one or more
of the dominant males. After the nursing period, the mother returns
to sea. For the next two months, weaned pups, called weaners, remain
on rookery beaches, venturing into the water for short periods of
time, perfecting their swimming and feeding abilities. Eventually,
the pups will learn to feed on squid, fish, and occasionally small
sharks.
STATUS:
The northern elephant seal is a conservation success story.
They were hunted to the brink of extinction, primarily for their
blubber, which was used for lamp oil. By 1910, it is estimated that
there were less than 100 elephant seals, all found on Guadalupe
Island off Baja California, MX. Today, the northern elephant seal
population is over 150,000 and is probably near the size it was
before they were over-hunted.
AT THE MARINE MAMMAL CENTER: From approximately mid-February through
the end of June, The Center's rescue and rehabilitation work focuses
on orphaned elephant seal and harbor seal pups. Usually these mammals
are washed away from the rookery during a storm and found stranded
on public beaches or along the rocky shorelines. These pups are
usually underweight. They also suffer from other diseases such as
northern elephant seal skin disease, parasites, and pneumonia.
May be reprinted for scientific and educational purposes
Revised 1/01
Learn more about the following:
Harbor Seal
California
Sea Lion
Steller Sea
Lion
Northern Fur
Seal
Guadalupe
Fur Seal
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