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Endangered Species
The Sea Otter
Enhydra
lutris

The sea otter is the largest species of the
weasel family and the smallest marine
mammal. It resides along the west coast of
North America including the Aleutian
Islands. A few centuries ago, it lived along
the shores from Baja California to Japan but
over zealous hunting pushed them close to
extinction. An estimated 150,000 to 300,000
otters may have lived along the west coast
when widespread hunting began in 1741. The
numbers slowly began to recover following a
treaty in 1911 between the United States,
Japan, Russia and Great Britain provided the
otter with protection fro hunting. Otters
are re-populating former haunts. Most of the
area west of Prince William Sound is now
recolonized. In British Columbia,
populations are growing at a rate of about
18% per year and otters are now regularly
seen in places on the west coast of
Vancouver Island and a few places on the
mainland coast. There are isolated
populations in Washington and California.
Their habit of habitually swimming on their
backs has made them readily identifiable and
a popular attraction among the marine
animals.
The sea otters distinguishable features
include large flipper like hind limbs,
flattened molars and flattened tail. Males
measure about 1.2 to 1.4 meters in length
and females are about 1.0 to 1.4 meters
long. Males weigh up to 45 kilograms and
females reach 33 kilograms. Otters that
reach adulthood can live for about 15 to 20
years in the wild. There are three
recognized sub species. Enhydra lutris
kenyoni occurs in Washington
north through the Aleutian Islands.
Enhydra lutris lutris occurs in the
Commander Islands to northern Japan, and
Enhydra lutris nereis is found in
California.
Sea otters live near the shore of the west
coast where they eat mostly marine
invertebrates. They glean the ocean bottom
by making brief dives. Studies in California
indicate that some individuals might
specialize on a few species of prey that
they appear to learn form their mothers.
Food items are opened by gnawing or
hammering against a rock held on its
belly.
Female otters become sexually mature at
about 3 to 5 years of age. Adult males
defend territories against other males.
Females move freely between these
territories briefly forming a bond with
males for mating. Gestation requires about
six months. Single pups are born annually.
Males reach sexual maturity at between 5 and
7 years of age.
Young males disperse away from groups soon
after weaning to establish their own
territories. Females tend to stay close to
where they were born. Otters will form into
rafts numbering from a few individuals to
several hundred otters.
The sea otter is well known for its ability
to limit the distribution and abundance
invertebrate prey. They have been described
as keystone species for their ability to
influence the presence of other species in
an ecosystem.
Sea Otter Identification
Sea Otter Distribution Maps
Sea Otter Pictures
Sea
Otter Photos by Tom Middleton
Grizzly
Bear Photos by Tom Middleton
Killer
Whale Photos by Tom Middleton
Blue
Whale Photos by Tom Middleton

More Sea Otter
Information, Sea Otter Photos and Sea Otter Video
Sea Otter Links
Pwlf.org
Sea Otter
www.otter.org
INTERNATIONAL OTTER SURVIVAL FUND
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