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| SCIENTIFIC
CLASSIFICATION |
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| COMMON
NAME: |
sea
otter |
| KINGDOM: |
Animalia |
| PHYLUM: |
Chordata |
| CLASS: |
Mammalia |
| ORDER: |
Carnivora |
| FAMILY: |
Mustelidae |
| GENUS
SPECIES: |
Enhydra
lutris |
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| DESCRIPTION: |
In
appearance, sea otters are stouter and have larger
ribcages, smaller tails and blunter muzzles than
other species of otters. Yet, sea otters do possess
the fine, dense fur coats characteristic of the
Mustelidae. Their forefeet are small and dexterous
with retractile claws and the flipper-like hind
feet are broad and webbed. Juvenile sea otters tend
to be a uniform dark-cinnamon brown while adults
develop lighter gray or buff coloration on their
heads. |
| MALE |
In
general, mature male sea otters tend to be slightly
larger than females of their respective subspecies. |
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| SIZE: |
Alaskan
sea otters are slightly larger than California sea
otters |
| MALE |
Male
Alaskan sea otters reach lengths up to 148 cm (58
in.) and male California sea otters average 122
cm (4 ft.) |
| FEMALE |
Female
Alaskan sea otters measure up to 140 cm (55 in.)
in length |
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| WEIGHT: |
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| MALE |
Mature
male Alaskan sea otters weigh up to 39 kg (85 lb.),
while California sea otters average 29 kg (64 lb.) |
| FEMALE |
Adult
female Alaskan sea otters can reach weights of up
to 33 kg (72 lb.), and female California sea otters
weigh on average 20 kg (44 lb.) |
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| DIET: |
A
sea otter has a metabolic rate much higher than
most mammals of similar size, and must consume large
quantities of food. Adult sea otters may eat as
much as 9 kg (20 lb.) of food each day. Among their
food preferences are sea urchins, crabs, abalone,
clams, mussels, octopus, and fishes. Most sea otters
specialize in only a few types of the available
food items. |
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| GESTATION: |
Approximately
4-9 months with an average of 6 months; probably
includes a 2-3 month period of delayed implantation |
| ESTRAL
PERIOD |
The
reproductive cycle in California sea otters is about
12 months. If a female's pup doesn't survive, she
may experience postpartum estrus. |
| NURSING
DURATION |
Approximately
6-8 months (wean) |
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| SEXUAL
MATURITY: |
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| MALE |
Approximately
5-6 years; usually don't actively breed for several
more years |
| FEMALE |
Approximately
4 years |
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| LIFE
SPAN: |
On
average, 10-15 years with some individuals living
more than 20 years in zoological parks |
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| RANGE: |
In
coastal regions throughout the eastern North Pacific
Ocean. Alaskan sea otters inhabit the coast of Alaska,
including the Aleutian and Commander Islands. California
sea otters are found off the coast of central California,
from Half Moon Bay to Pt. Conception. |
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| HABITAT: |
Typically
found in coastal waters no further away than 1 km
(0.6 mi.) from shore. The Alaskan sea otter has
a greater tendency to haul out (come to shore) than
the California sea otter. |
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| POPULATION: |
REGIONAL |
The
California population is still small - roughly 2,200-2,800
sea otters |
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| STATUS: |
IUCN |
Endangered |
| CITES |
Appendix
II (California subspecies is listed as Appendix
I) |
| USFWS |
Overall,
listed as threatened. The population south of Pt.
Conception, CA is listed as Experimental Population/Non-essential |
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| 1. |
The
sea otter's dark brown fur is the finest and densest
of any animal fur. On an adult animal, there are
an estimated 650,000 hairs per square inch. A sea
otter relies on its fur to keep warm-it doesn't
have an insulating layer of blubber as other marine
mammals do. Natural oils in a sea otter's fur repel
water and trap tiny air bubbles, providing a layer
of warm air between the otter's skin and the harsh
elements of its environment. Sea otters may spend
as much as 48% of the daylight hours grooming their
fur. |
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| 2. |
Sea otters sleep, rest, and usually swim by paddling
with their hindflippers on their backs. California
sea otters spend almost all of their time in the
water, while Alaska sea otters often sleep, groom,
and nurse their young on land. |
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| 3. |
Tool use is an unusual behavioral trait seen only
in sea otters and a few other types of animals.
An otter may remove an abalone by repeatedly hitting
it with a rock. It also may use a flat rock to break
open the shells of crustaceans and mollusks. While
holding the rock on its chest, the otter pounds
the animal on the rock until it breaks or opens. |
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| Sea
otters once were abundant along most of the coastal
North Pacific Ocean. That was before fur traders
hunted them for their thick, luxurious pelts. By
the year 1900, sea otters were nearly extinct. Protected
since 1911, Alaska sea otters have made a comeback.
Because
they rely on their dense fur for insulation from
the chilly ocean water, sea otters are particularly
vulnerable to the detrimental effects of an oil
spill. If a sea otter swims into an oil spill,
its fur becomes soiled and loses its insulating
qualities, allowing water to penetrate to its
skin, causing hypothermia and ultimately, death.
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|
|
Byrum,
J. Otters. SeaWorld Education Department
Publication. San Diego. SeaWorld, Inc. 1997.
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|
|
Jefferson, T.J. Leatherwood, S. and M.A. Webber.
FAO Species identification Guide. Marine Mammals
of the World. Rome. FAO, 1993. |
|
|
Nowak, Ronald M. (ed.). Walker's Mammals of
the World. Vol. II. Baltimore: Johns Hopkins
University Press, 1991.
|
|
| Parker,
S. (ed.). Grizmek's Encyclopedia of Mammals.
Vol. IV. New York: McGraw-Hill Publishing Co.,
1990. |
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| Reeves,
R. R., Stewart, B.S., Clapman, P.J., and J.A. Powell
(Peter Folkens illustrator). National Audubon
Society: Guide to Marine Mammals of the World.
New York: Random House, 2002. |
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| Reeves,
R.R., Stewart, B.S. and S. Stephen. The Sierra
Club Handbook of Seals and Sirenians. San Francisco:
Sierra Club Books, 1992. |
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| http://animaldiversity.ummz.umich.edu |
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