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CANADIAN WATERS |  |
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 Creature Feature!
Seals, Sea Lions, Walruses and Otters!Seals!
Seals are carnivorous marine mammals that have fins or flippers instead of feet. There are three families of seals; the Eared Seals, True Seals and the Walrus. Seals are widely distributed throughout the marine environment of the arctic and temperate zones including a few tropical species of seals such as the monk seal. What makes seals so unique?All three families of seals possess a neat adaptation to their aquatic habitat. Unlike their ancestors, seals live most of their life in the sea. They only move onto land (shores or Ice Floes) for breeding, raising their young and escaping from predators. Eared Seals!The eared seals have long, flexible necks and small external ears. They have rear flippers that can turn forward. This feature enables them to support their body on land and they can use all of their limbs on land. Sea lions and fur seals are the two types of seals that make up this group. Sea Lions
The sea lions are larger than the fur seals. The adult male Steller's sea lion (North Pacific Ocean) can reach a maximum length of 3.5 m (12 ft) and a maximum weight of 1100 kg (2400 lbs). The females of this species are much smaller than the males, weighing up to 350 kg (up to 770 lb).
Fur SealsFur seals look a lot like sea lions physically, but they have a rich, silky undercoat of fur. There are two genera in this group: one which resides in the southern hemisphere and the other in the North Pacific Ocean and the Bering Sea. Among the two genera, there are six to eight species of the southern fur seal. The single northern species is the northern fur seal, which breeds in the Pribilof Islands of the Bering Sea. The male, or bull, is mostly dark brown in color, shading to gray at the shoulders. Reaching maturity at about the age of seven years, the bull attains a length of 2 m (6 ft) and a weight of 250 kg (550 lb); the female, or cow, matures at three years and attains an average weight of 52 kg (115 lb). Large, older bulls have harems of as many as 40 cows and battle off rival males until defeated. Immature and bachelor males congregate on beaches removed from the breeding grounds. As winter approaches, the fur seals migrate southward to latitudes of Baja California. True Seals!
The Walrus The walrus is a large marine mammal that can be found in Arctic regions at the edge of the polar ice along the northeastern coasts of Canada and Siberia, Kamchatka, the northwestern coast of Alaska, Greenland, northern Norway, and Ellesmere Island. There are two populations of the walrus: the Atlantic walrus and the Pacific walrus. Walruses can turn their rear forward like the eared seals. Therefore they can also use all four limbs when moving onto shore. Walruses range in length from 2.7 to 3.5 m (8.9 to 11.7 ft) and they can weigh from 800 to 1700 kg (1800 to 3700 lb). As in many groups of animals, males are larger than females. Both male and female walruses have huge bodies with thick, wrinkled, hairy skin like an elephant. Both have relatively small heads with no external ears; a fold of skin marks the location of the ear. They have broad, bristled muzzles; and enormously elongated upper canine teeth forming heavy tusks. The tusks, about 1 m (about 3 ft) long in some males, are used as weapons in fighting and as hooks in climbing on the ice. Although it was once thought that the tusks were also used to rake the ocean bottom for mollusks and shellfish, which constitute the principal food of the walrus, it is now believed that the sensitive whiskers and fleshy snout play a primary role in detecting and removing prey from the ocean floor.
Walruses are very social animals. They group together in herds that can reach up to several thousand animals on or near to shore or ice floes. The sound that a herd makes can be heard from great distances. Walruses are very gentle creatures. When attacked however, the whole herd will come to the aid the group member in trouble. The polar bear is the main natural predator of the walrus. Humans hunt the animal for its ivory tusks and for its flesh and blubber.
The Sea OtterSea otters may be similar to seals on the outside, but they are not closely related. Sea otters are related to the weasel family, but they share the sea with seals.
The sea otter lives on the shores of North America and Asia on the North Pacific Ocean sides. It is similar in appearance to the Eurasian and North American otters. Sea otters can reach a length of 1 to 1.2 m (3.3 to 4 ft). They feed chiefly on molluscs and sea urchins. Their large, flat teeth help them to crush the hard shells of their hard food. Sea otters also use rocks as a tool to open up shellfish while they swim on their backs. The female sea otter gives birth to a single offspring. She nurses her young while lying on her back in the water. The sea otter is the only marine mammal that lacks an insulating layer of blubber. Blubber serves to protect the animal from the frigid ocean waters. To compensate for this lack of blubber, the sea otter has to constantly clean its fur which allows an insulating layer of air to be trapped against the skin.
ReferencesBearded Seals Harp Seals Harbour Seal Hooded Seal Northern Fur Seal Ringed Seals Sea Otters Steller's Sea Lion Walrus Microsoft Encarta. 1996 Edition. Microsoft Corporation Microsoft Oceans.1995 Edition. Microsoft Corporation. National Audubon Society Pocket Guide: Familiar Marine Mammals of North America. 1997. Vaughan, Terry A. 1986. Mammalogy. Saunders College Publishing, Toronto. 576pp. Artwork: |
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Created: 2001-06-08 Updated: 2005-01-27 Reviewed: 2003-09-03 |
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Did You Know?... The "seal" that is the most trained for exhibition
in movies and zoos is the small California sea lion, Zalophus californianus,
found off the California coast.
The true seals lack external ears and they have a short inflexible neck with
undeveloped front limbs. Their front limbs have claws which help them to crawl
up on rocks and ice floes. The hind limbs do not rotate forward and are positioned
vertically during swimming like a dolphin's tail. True seals are better adapted
to aquatic life than their relatives the eared seals. Unlike the eared seals,
true seals have trouble travelling on land as they move by wriggling and contorting
their entire body.
Elephant seals got their name from their trunklike snout and their great size.
The northern elephant seal can attain a length of 6.7 m (22 ft).
Scientific Classification: Seals make up the families Otariidae, Odobenidae,
and Phocidae of the suborder Pinnipedia. Steller's sea lion is classified as
Eumetopias jubatus, the California sea lion as Zalophus californianus,
the northern fur seal is classified as Callorhinus ursinus, the harbor
seal as Phoca vitulina, the harp seal is classified as Pagophilus
groenlandica, the ringed seal as Pusa hispida, the gray seal as Halichoerus
grypus, the hooded seal as Cystophora cristata and the northern elephant
seal as Mirounga angustirostris.
