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Northern Elephant Seal
Behaviour
Northern Elephant Seal
Breeding Behaviour
Elephant seals use many islands off the coast of California
and Mexico, including the Farallons, Año Nuevo, San Miguel,
Santa Cruz, San Nicholas, San Clemente, Islas Coronado,
Guadalupe, and
San Benito.
Male elephant seals are very large up to 4.2 meter long and
2300 kilograms in weight (Wilson and Ruff 1999). Females are
smaller than males at about 2.5 meters long and weighing about
650 kilograms. The elephant seal is polygynous and breeds from
December to the end of February. Males compete for matings by
creating dominance hierarchies backed by threats, displays and
fights. Among the most audacious display involves inflation of
the nose. A dominant male might have up to 50 females with him
on his beach territory (Wilson and Ruff 1999). These males
might forego feeding for three months to ensure matings.
Females give birth to offspring with black pelage that molt
after weaning to silvery white. Mothers remain on land with
their pups to suckle them for about 4 weeks. Females then seek
out matings and depart to sea for about 3 months. Their pups
remain on the nursery islands for another month or more before
leaving to feed in the ocean. Northern elephant seal females
have delayed implantation of the ova. The fertilized egg
attaches to the uterine wall where development is arrested for
2-3 months. Once the egg begins to develop, the gestation
period takes about 8 or 9 months (Wilson and Ruff 1999).
Females can first give birth at 2 years of age but most begin
when they are four or more years old. Males become sexually
mature at about 5 years old but are not able to compete for
matings until they are about 8 years old. Males live for about
12 years and females for about 20 years.
Northern Elephant Seal
Molt
Juvenile elephant seals haul out on land to undergo a molt in
April, adult females in May, young males in June, and adult
males in July and August (Wilson and Ruff 1999). Large patches
of hair and skin fall out at this time making the animals look
sick and diseased.
Northern Elephant Seal
Feeding Behaviour
About 90% of the time is spent underwater at great depths of
650 meters or more feeding on squid or small fish. Elephant
seals stay submerged during these dives for 20 minutes or
more. They forage alone. On the surface, elephant seals
resemble upended logs.
Killer whales and great white sharks will attack elephant
seals.
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