Sea otters are the smallest of all marine mammals. At birth,
they are about 22 inches long and weigh approximately five
pounds. Adult males grow to be about 58 inches long and weigh
60–85 pounds. Unlike other marine mammals, sea otters do not
have a protective layer of blubber to shield them from cold
water. To compensate, they have extremely thick fur that traps
warm air between hairs and insulates the body.
Sea otters consume approximately 20% of their body weight in
food daily. They dive to the bottom of their shallow shoreline
habitat to feed upon sea urchins, clams, oysters, and other
shellfish. Only strong males are able to catch fish. The otters
return to the surface with their prey, float on their backs,
and strike the shellfish together or against rocks to pry them
open.
Sea otters have a strong influence on coastal ecosystems.
They restrict the sea urchin populations in near-shore
habitats, allowing kelp forests to flourish (sea urchins graze
heavily on kelp). It's easy to see where sea otters thrive:
Just look for abundant kelp. Pups are born (generally one per
litter) after a six-month gestation period and remain with
their mother for 12 weeks. Fathers play no role in the
offspring's upbringing; the two sexes tend to remain separate
except when breeding.
There are three subspecies of sea otters, two of which are
in the United States. The Southern, or California, sea otter
(Enhydra lutris nereis) is represented by only one
population in California and is declining at a disturbing rate.
The Northern sea otter (Enhydra lutris kenyoni, found in
Washington, Alaska, and Canada) and the Russian sea otter
(Enhydra lutris lutris, found in Russia and Japan) are
also facing conservation threats.
