Order: Carnivora
Family: Mustelidae
Genus & Species: Enhydra lutris
APPEARANCE
Sea otters are one of the largest of the otter species, with a body length of
3-4 ft and a tail length of 10 in. The males weigh 50-100 lbs, the females
30-70 lbs. The fur is dense and thick and is silky and velvety to the touch.
The guard hairs are long, 1.4 in, and the underfur is 0.8 in long. They have
no blubber for warmth, unlike other marine mammals, and therefore rely
heavily on their fur. Up to 1,600,000 hairs can occupy a square inch on their
back. The hair colour is black to dark brown on the back and lighter on the
belly. The head and throat are straw-coloured. The hairs on the back are
often white-tipped.
The forefeet are stumpy and end in small claws. The back feet are long and
webbed and aid the sea otter in swimming. The head is large and blunt and
the neck is short. The eyes are small and the ears are short and pointed,
almost hidden in the fur. Four incisors are located on the lower jaw, unique
among carnivores, and the molars are broad and flat. The nose is large and
diamond-shaped, with a "moustache" of whiskers right below it. This gives
the sea otter the humorous expression of an old man. The paws are furless.
The fur is key to their survival and must be groomed regularly. If it
becomes matted with oil, they will die of hypothermia. Sea otters have a
strong sense of smell, sight and touch. They have a life span of up to 20
years.
HABITAT
Sea otters are found along the coastal and island waters of the north Pacific
from the Aleutian islands of Alaska south to mid-California. On the western
side they are found from Russia south to Japan. Today they are flourishing
in Checleset Bay and the Baja Reef.
Sea otters spend their entire lives in the water and are rather awkward on
land. They live in beds of kelp, which are large plant-like protists, and play
a vital role in their society by feeding on the sea urchins that can destroy
kelp beds.
FOOD
Sea otters are strictly carnivorous in nature, feeding on crabs, sea urchins,
abalones, fish, octopuses, clams, and mussels. They dive down to depths of
100 ft to catch their meal, and often rise to the surface with a shellfish and a
smooth stone. They eat lying on their backs with their belly as the table.
Like chimpanzees, they can use tools, and will place the smooth stone on
their belly, repeatedly smashing the shellfish on it until the shell breaks off.
Unlike river otters, sea otters use their forearms to catch their food, and can
stay submerged for up to a minute to dig for clams. Because sea urchins
provide little nourishment, they must eat 1/4 of their body weight, 35-40
urchins, each day.
BREEDING
Sea otters have no mating season. Males reach sexual maturity ate 6-9 years
of age, females at 4 years. The males mate with more than one female and
do not help in raising the young. The females give birth to one pup every
two years. The gestation period varies as they can delay the embryo's
development to ensure that it is born at a favourable time of the year. The
pups are usually born 6-9 months after fertilization. The young are born on
the land with fur, eyes open, and a full set of milk teeth. They are taken
straight into the water and stay with the mother for one year.
ENEMIES
The sea otter has two formidable enemies in the form of killer whales and
great white sharks. Because of their fur, they were at one time also hunted
close to extinction by European settlers and Russians. By 1911, only 2000
sea otters remained in North America. Today, hunting is illegal, and sea
otters are making a slow recovery. Unfortunately, oil spills and chemicals,
coupled with their slow reproductive rate, is keeping them on the
endangered list.
MISCELLANEOUS
Sea otters are found in groups called "rafts." Males are in separate rafts
then females, and not all sea otters are found in rafts. They range in size
from 10-100 individuals and serve no purpose other than to socialize with
others.
To sleep, sea otters float on their backs with their paws covering their eyes.
They wrap themselves up in kelp so that they do not float away.
RELATIVES
There are three subspecies of sea otter: E. l. nereis, E. l. lutris, and E. l.
gracilis.
RESOURCES CITED
1. "Sea Otter" Wildlife Fact File, IM Pub, USA
2. "Sea Otter" Funk & Wagnall's Wildlife Encyclopedia, pg 2021, vol 17,
BPC Pub Ltd, USA, 1974
3. otternet.com/species/seaotter.htm
4. www.wwfcanada.org/facts/seaotter.html
5. www.seaotters.org/index2.html
6. www.ghs.com/people/jimmy/ottertx1.html
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