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The southern sea otter is a carnivore. Sea
otters grow to approximately four feet in length, with the male
weighing approximately 65 pounds and females about 45 pounds.
Unlike other marine mammals, sea otters do not have a thick
layer of blubber and rely upon their dense fur for insulation.
The average person has about 600,000 hairs on their head; the
sea otter has two million hairs per square inch. The fur is
sensitive to soiling from oil or other contaminants. Soiling of
the fur by oil generally results in death.
This aquatic member of the weasel family is found along the
coasts of the Pacific Ocean in North America and Asia. The sea
otter spends most of its time in the water but, in some
locations, comes ashore to sleep or rest. Sea otters have webbed
feet, water-repellent fur to keep them dry and warm, and
nostrils and ears that close in the water.
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Otters tend to grow white patches on their head
as they grow older. Otters are equipped with
pouches or flaps of skin under each front leg
that they use to store food while foraging.
Sea otters are the only otters to give birth in the water. Mothers nurture their
young while floating on their backs. They hold infants on their chests to nurse
them, and quickly teach them to swim and hunt. Adult female otters give birth to
a single pup nearly every year. Pups have long
black or brown hair and are so buoyant that they
can not dive underwater. Pups are often seen
bobbing beside or resting upon mothers.
Sea otters are meticulously clean. After eating, they wash themselves in the
ocean, cleaning their coat with their teeth and paws. They have good reason to
take care of their coats—it helps them to remain waterproof and insulated
against the cold. Sea otters have thick under-fur that traps air to form an
insulating layer against the chilly waters (they have no insulating fat). This
coat is invaluable to otters, but it has worth to some humans as well.
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The sea otter is the smallest marine mammal in North America yet
has a huge affect on its ecosystem, enhancing both diversity and
primary productivity. Sea otters are known to be a keystone
species, an indicator species and an umbrella species. They have
a remarkable impact on conservation of the near-shore marine
environment.
In California, sea otters spend between 17 to 38 percent of
their time foraging and 50 to 68 percent of their time resting.
Sea otter populations at carrying capacity spend 51 to 58
percent of their time foraging and 32 to 34 percent of their
time resting.
From evidence found in the fossil record, sea otters and their
ancestors have been a component of California's ecosystem for
the past five million years.
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Sea otters often float at the water's surface,
lying on their backs in a posture of serene
repose. They sleep this way, often gathered in
groups. Otters sometimes float in forests of
kelp, or giant seaweed, in which they entangle
themselves to provide anchorage in the swirling
sea.
Sea otters do more than sleep while floating on
their backs. They are often seen with a clam or
mussel and a rock that has been deftly snared
from the ocean floor. Otters will place the rock
on their chests, and repeatedly smash the
shellfish against it until it breaks open to
reveal the tasty meal inside. They also dine on
such aquatic creatures as sea urchins, crabs,
squid, octopuses, and fish. Sea otters eat the
equivalent of 20 to 30 percent of their body
weight per day to maintain their body heat.
It is thought that the only natural predator of
sea otters are sharks. The range of the
California Sea Otter is concentrated along a 200
mile stretch of the central coast. |
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Sea otters were hunted for their fur to the
point of near extinction. Early in the 20th century only 1,000
to 2,000 animals remained. Today, 100,000 to 150,000 sea otters
are protected by law.
The California sea otter is an endangered species success story
that is not quite successful. California sea otters are listed
as "threatened" under the Endangered Species Act and "depleted"
under the Marine Mammal Protection Act.
Wiped out by the Pacific maritime fur trade, sea otters were
believed to be extinct from California by the early 1900s. A
small, remnant population of survivors was found living off the
coast of Big Sur in 1938. Legal protections allowed the
population to grow. The California population increased to 2,400
in 1995 before mysteriously beginning to decline. It began to
grow again in 1999, and has grown in fits and starts until 2009,
when the population entered another decline.
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