Common Name: California Sea Lion
Class: Mammalia
Order: Pinnipedia
Family: Otariidae
Genus:
Zalophus
Species:
Zalophus californianus
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Taxonomy/Description
California 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. The California Sea Lion's scientific name
is Zalophus californianus, which means "large crest belonging
to California". "Large crest" refers to the very prominent sagittal
crest present on male sea lions.
When sea
lions are born they are almost black in color. But adults can be
almost any shade of brown ranging all the way to a very light tan.
Sea lions, like other eared seals, are very sexually dimorphic.
This means that it is very easy to distinguish adult males from
females. For one thing, males tend to be much larger in overall
size than females. Males may weigh as much as 1000lbs, with females
can reaching 300lbs. Adult males are distinguished by the
pronounced sagittal crest on their skulls. This gives the
appearance of a "bump" on the top of their head. Females also tend
to be lighter in color. California sea lions live to about 25 years
of age.
Habitat/Diet
Their
range spans the Pacific coast, from British Columbia to northern
Mexico. Subspecies inhabit the Galapagos Islands and coastal
Japan. The diet of sea lions is quite varied. They are
opportunistic feeders that will mainly eat fish. Other small marine
creatures like lobster , squid, octopi, crabs, clams, crustaceans,
and mollusks are eaten when available. California sea lions are
capable of reaching speeds of 15 to 20 miles per hour, dive up to
450ft, and stay submerged 20 minutes to hunt for prey. Their
whiskers, called vibrissae, detect vibrations in the water from prey
species.
Behavior/Reproduction
Sea
lions, like other pinnipeds, have an amazing feature that helps them
to thermoregulate. They have have special shunts within their
bodies called AVA's (arterio-venal anastomosis) which assists them
in regulating their body temperatures. Depending on their
surroundings and on whether they feel too cold or too warm, they can
alternatively reduce their blood flow to their skin or increase it
significantly. For example, on a deep dive into cold water a sea
lion will conserve its heat by closing down the blood vessels
leading to its flippers so that most of its blood is kept under the
blubber of its main body. Alternatively, on a warm day, a sea lion
may greatly dilate those same blood vessels and float along with its
flippers in the air as its skin soaks up the heat from the sun's
rays. They bask in the sun during the day and feed at night.

Colonies
may reach numbers of 1,000 or more individuals. At breeding season,
males will come ashore to the beaches first and battle with each
other for territories. When the females come ashore later, they
favor the males that have obtained the best territories and in this
way harems develop with about sixteen females for every territorial
male. Ritualized fighting and large size is the key to reproductive
success among male sea lions and this is undoubtedly what has led to
the extreme sexual dimorphism in this species.
Most
pups are born in June or July and nurse for at least six months or
more. A mother will give birth to only one pup. Mother and pups
recognize each other by vocalizations, sight, and smell. They are
hunted by killer whales, sharks and humans.
Sea
lions are very beautiful, intelligent and playful. In the wild, we
saw them deliberately allowing themselves to get knocked around in
the waves and playing "king of the mountain" on cliffs. Because of
their adaptive natures and their playfulness, they are often
included in zoos and aquariums around the world where they are
trained to perform various behaviors in shows and demonstrations.

Conservation
Their
population is growing and is now at approximately 200,000, but even
though they are protected by law, they are still threatened by over
fishing, fishing nets, and water pollution. One example of sea
lions and humans living side by side takes place in San Francisco,
California. A colony of California sea lions lives on Pier 39, a
dock right next to San Francisco's boardwalk! Here tourists and
conservationists can view these amazing creatures in a place chosen
by the sea lions