seal, carnivorous aquatic mammal with front and hind feet modified as flippers, or fin-feet. The name seal is sometimes applied broadly to any of the fin-footed mammals, or pinnipeds, including the walrus, the eared seals (sea lion and fur seal), and the true seals, also called earless seals, hair seals, or phocid seals. More narrowly the term is applied only to true seals. The so-called performing seal of circuses is actually a sea lion.

Characteristic Features of All Seals

Pinnipeds have streamlined bodies, rounded in the middle and tapered at the ends, with a thick layer of fat beneath the skin. Their limbs are short and their feet are long and webbed, forming flippers. The sea lions and fur seals (family Otariidae) and the walrus (family Odobenidae) are able to turn their hind flippers forward for walking on land; they swim chiefly by a rowing action of the long front flippers. The true seals (family Phocidae) are unable to rotate the hind flippers. They progress on land by wriggling on their bellies, pulling themselves with the short front flippers; in the water they are propelled by a side-to-side sweeping action of the hind flippers.

Nearly all pinnipeds are marine, and most inhabit cold or temperate regions. Some spend most of the year in the open ocean, while others inhabit coastal waters and spend varying amounts of time on shores, islands, or ice floes. Occasionally they ascend rivers. All pinnipeds leave the water at least once a year, at breeding time. In nearly all species the females give birth a year after mating, so that the births take place on land, just before breeding begins. The pups are nursed during the period, usually of several months duration, spent on land. Some species spend most of the year far from their breeding grounds; the northern fur seals make particularly lengthy migrations each year. Most pinnipeds have diets of fish and shellfish; many are bottom feeders, with physiological adaptations for deep diving. They have acute hearing and some, if not all, make use of echolocation (sonar) for underwater navigation.

True Seals

True seals are called earless seals because they lack external ear projections; they have functional inner ears. They have short, coarse hair, usually with a close, dense undercoat. Their color and pattern vary with the species; many are spotted. The pups of most species have fluffy coats of a light color. True seals are generally polygamous and gregarious, but most do not form harems at breeding time, as do the eared seals. Some species have definite migrations, but in most the seals spread out after breeding, singly or in groups, over a wide area of ocean. Some polar species migrate in winter to avoid the advancing ice; members of other species winter under the ice, surfacing through holes to breathe.

Most true seal species fall into one of three geographical groups: northern, antarctic, and warm-water species. Nearly all are marine, but the Baykal seal (Pusa siberica) is confined to the freshwater Lake Baykal of Siberia, and the Caspian seal (P. caspica) to the brackish Caspian Sea. In addition several populations of the normally marine harbor seals and ringed seals are found in freshwater lakes. The northern seals include two species of temperate coastal waters: the common seal, or harbor seal, of the N Atlantic and N Pacific, and the larger gray seal of the N Atlantic. The former is the only seal frequently seen off U.S. coasts. The Greenland seal, or harp seal, is found in the arctic Atlantic; the ribbon seal in the arctic Pacific. The small ringed seal and the larger bearded seal are circumpolar arctic species. Antarctic seals include the voracious leopard seal, which feeds on penguins and other sea birds, and the Ross, Weddell, and crabeater seals. The warm-water seals are the Mediterranean, Caribbean, and Hawaiian species of monk seal. A fourth group includes the elephant seal and hooded seal. There are two elephant seal species, one of the Northern and one of the Southern Hemisphere. They are distinguished by their immense size and trunklike snouts. The hooded seal, distinguished by an inflatable bladder over the snout, is found in the arctic Atlantic.

Sealing

Seals have been used by the Eskimo and other northern hunting peoples for food, oil, and hides. Commercial sealing has been largely confined to a few species, most notably the fur seal. Commercially important species of true seals are the harp seal, whose pups are valued for their fluffy white coats, and the ringed seal. The hunting of these seals is regulated by international treaties, and they are not in danger of extinction. The elephant seals were formerly hunted for oil and almost exterminated, but they are now protected and are stabilized or increasing in numbers. The monk seals have been greatly depleted by hunting in past centuries and their survival is threatened, although they are no longer of commercial importance. The Caribbean monk seal is believed by some authorities to be extinct. The ribbon seal and Ross seal are not much hunted; estimates of their populations have varied considerably, but they are not thought to be endangered.

Classification

Seals are classified in the phylum Chordata, subphylum Vertebrata, class Mammalia, order Carnivora, suborder Pinnipedia.

seal, stamp made from a die or matrix of metal, a gem, or other hard substance that yields an impression on wax or other soft substance. The use of seals is very ancient, examples of great antiquity occurring in China, Egypt, Greece, Rome, and other places. The most common form was the seal ring, of which the gem formed the seal. Ecclesiastical seals, used in the 9th cent., reached their highest perfection in the 13th and 14th cent. The use of seals with emblematic designs antedates the development of the escutcheon and is therefore important in the history of heraldry. Edward the Confessor was the first English king to adopt a Great Seal for the kingdom. Heraldic or emblematic seals are in wide use by national, state, and local authorities, by institutions of all kinds, and in the certification of legal documents. A committee was appointed by the Continental Congress on July 4, 1776, to prepare a device for the Great Seal of the United States (see United States, Great Seal of the).

harp seal, crested earless, or true, seal, Phoca groenlandica, found in the N Atlantic around Greenland and the White Sea. In the spring, harp seals migrate southward to assemble in large groups to breed near the Newfoundland and Norwegian coasts. The young, born on ice floes, are covered with a fluffy white coat from birth to weaning (about 12 to 18 days) and are hunted for their fur, meat, and skin. The clubbing to death of baby seals aroused much protest in the 1970s, and trade in their white furs has declined after Europe banned imports in the mid-1980s. A decade later, however, concerns over the seals' affect on the cod fisheries led to increased quotas and the return of large commercial operations to the annual hunt, but killing of white-coated baby seals is banned. The fur gradually darkens to gray as the young seals mature. The old males are marked with a brown crest on each side, suggesting the outline of a harp. Harp seals, sometimes seen as far S as Maine, are classified in the phylum Chordata, subphylum Vertebrata, class Mammalia, order Carnivora.

harbor seal, most commonly seen seal of the Northern Hemisphere, Phoca vitulina. Harbor seals are found along coasts and in sheltered bays and harbors of North America, Europe, and NE Asia. They range farther south than any other northern seal, being found in North America as far S as New Jersey and S California. They range north to the southernmost limits of the ice cap. Also known as common seals, hair seals, and leopard seals, they enter rivers, and are even found in the Great Lakes. Small seals, they reach a length of up to 6 ft (180 cm) and a weight of up to 250 lb (110 kg). Their coats are gray with white spots or yellowish with gray or black blotches. Harbor seals are solitary hunters; they feed on fish, mollusks, and crustaceans, coming ashore to rest and sleep. They may gather in large numbers on rocks or beaches, especially at the mating season. They are polygamous and the female produces a single pup in early spring. Small colonies of several families each occupy particular locations in the water, usually near rocky shores or islands, and may remain there for many generations. Their greatest enemies are sharks and killer whales. Harbor seals are classified in the phylum Chordata, subphylum Vertebrata, class Mammalia, order Carnivora, suborder Pinnipedia, family Phocidae.

fur seal, fin-footed marine mammal of the eared seal family (Otaridae), highly valued for its fur. Like the closely related sea lion, the nine species of fur seals are distinguished from the true seal by external ears and the ability to turn their hind flippers forward for walking on land. The northern, or Alaskan, fur seal, Callorhinus ursinus, has an outer coat of long coarse hair known as guard hair and an inner coat of thick soft fur; it is the inner coat that is valued in the fur trade. Males are dark brown and females and young are grayish. The male is about 6 ft (1.8 m) long and weighs up to 600 lb (270 kg), while the smaller female is up to 4 ft (1.2 m) long and seldom weighs more than 110 lbs (50 kg). Herds of northern fur seals, mostly females and juveniles, winter in open ocean along the Pacific coast of North America, migrating in spring to breeding beaches that range from the Pribilof Islands in the Bering Sea to San Miguel Island off California. Adult males, who usually winter separately, arrive at the islands weeks ahead of the females. During the breeding season the most aggressive males establish individual territories and have harems averaging 40 to 50 females, which they defend against other males. Mating occurs after the birth of the young conceived the previous summer; each female bears a single pup after a gestation period of almost a year. The pups nurse for about a month but remain with the mother for another 2 or 3 months. Mothers often leave pups for days to feed on squid and fish. By the early 20th cent. the northern fur seal population was reduced to about 200,000 as the result of wanton slaughter. An international treaty signed in 1911 limited hunting to a fixed number of nonbreeding males per year. By 1976 the world population had increased to almost 2 million; since then it has declined, for reasons still unclear. The United States prohibited the hunting of fur seals in 1985. Southern fur seals, such as Arctocephalus gazella and other species, are similar in size and appearance to the northern fur seal. Although their fur is not considered desirable, they have been hunted almost to extinction. Both southern and northern fur seals migrate, while tropical species remain near their breeding grounds. Fur seals are classified in the phylum Chordata, subphylum Vertebrata, class Mammalia, order Carnivora, suborder Pinnipedia, family Otariidae. See also Bering Sea Fur-Seal Controversy, under Bering Sea.

false Solomon's-seal: see Solomon's-seal.

elephant seal or sea elephant, a true seal of the genus Mirounga. It is the largest of the fin-footed mammals, or pinnipeds, exceeding the walrus in size. There is a northern species, Mirounga angustirostris, along the Pacific coast, and a larger southern species, M. leonina, that breeds on sub-Antarctic islands. Males commonly reach a length of 18 ft (5.5 m) and a weight of 5,000 lb (2,270 kg); the female may measure 10 ft (3 m). A hollow, flabby snout about 15-18 in. (38-45 cm) long on the male gives these seals their name. During the 3-month breeding season the largest bulls stake out territories and try to attract and hold as many females as possible. When a bull is sexually excited or angry it snorts air from the proboscis into the throat, producing sounds heard miles away. Bulls do not eat during breeding, but females without pups feed on squid, fish, crabs, and other organisms that compose their main diet. These earless seals are graceful in water, diving to 2,275 ft (700 m) for food. Seal hunters, who extracted oil from blubber, pushed the northern species to the edge of extinction in the 19th cent. In 1911 the Mexican government extended protection to the single remaining M. angustirostris colony on Guadalupe Island off Baja California; the United States eventually followed suit. By the early 1990s an estimated 60,000 animals were found on island rookeries off Baja and central California. Elephant seals are classified in the phylum Chordata, subphylum Vertebrata, class Mammalia, order Carnivora, suborder Pinnipedia, family Phocidae.

United States, Great Seal of the, official impression that validates a United States government document. It was adopted by the Continental Congress in 1782 and, with only minor changes in the design, remains in use today. In the center of the seal is an American eagle. It holds in its beak a scroll inscribed "E pluribus unum"; in one talon is an olive branch; in the other, a bundle of thirteen arrows. A shield with thirteen alternate red and white stripes covers the eagle's breast, and over its head a cloud surrounds a blue field containing thirteen stars. The Secretary of State is the official custodian of the seal, and it is only affixed to certain classes of documents (e.g., foreign treaties, presidential proclamations, and commissions installing cabinet officers and other high executive officials).

Solomon's-seal, any plant of the genus Polygonatum, north-temperate perennial herbs of the family Liliaceae (lily family). The hairy Solomon's-seal (P. pubescens) and the smooth Solomon's-seal (P. biflorum) are well-known wildflowers in most of North America. They characteristically have dark blue berries at each pair of leaf axils. The name has been attributed to leaf scars on the rhizome that resemble seals. Species of Solomon's-seal were formerly used in applications for the skin, and the roots and young shoots have been used for food. They are often grown in wildflower gardens. False Solomon's-seal or wild spikenard (Smilacina racemosa), of the same family, is similar but has a cluster of red berries. It is unrelated to the true spikenards. Solomon's-seal is classified in the division Magnoliophyta, class Liliopsida, order Liliales, family Liliaceae.

Seal of the United States, Great: see United States, Great Seal of the.

Seal Beach, city (1990 pop. 25,098), Orange co., S Calif., on the Pacific coast; inc. 1915. It is a beach city with an active art colony. Transportation equipment and concrete are among the city's manufactures. U.S. naval stations are nearby.

Hudson seal: see muskrat.

Great Seal of the United States: see United States, Great Seal of the.

Bering Sea Fur-Seal Controversy: see under Bering Sea.

Nonmigratory, earless seal (Phoca vitulina) found throughout the Northern Hemisphere. Harbour seals are whitish or grayish at birth, generally gray with black spots as adults. The adult male may reach a length of about 6 ft (1.8 m) and a weight of almost 300 lb (130 kg); the female is somewhat smaller. Found along coastlines and in a few freshwater lakes in Canada and Alaska, the harbour seal is a gregarious animal that feeds on fish, squid, and crustaceans. It is of little economic value and in some areas is considered a nuisance by fishermen.

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Aquatic carnivore with webbed flippers and a streamlined body. Earless (true, or hair) seals (of the family Phocidae, with 18 species) lack external ears. In water, they propel themselves by side-to-side strokes of the hind limbs and maneuver with their forelimbs. On land, they wriggle on their belly or pull themselves with their forelimbs. Earless species include the elephant seal, harbour seal, harp seal, and leopard seal. The eared seals (family Otariidae, with five species of sea lion and nine of fur seal) have external ears and longer flippers. In water, they propel themselves by a rowing motion of their forelimbs; on land, they use all four limbs to move about.

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or sea leopard

Species (Hydrurga leptonyx) of generally solitary earless seal (family Phocidae) found in Antarctic and sub-Antarctic regions. It is the only seal that feeds on penguins, young seals, and other warm-blooded prey. It is slender and has a long head and long three-cusped cheek teeth. Named for its black-spotted gray coat, it attains a maximum length and weight (greater in the female) of about 12 ft (3.5 m) and 840 lbs (380 kg). It has a reputation for ferocity but is not known to make unprovoked attacks on humans.

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Migratory earless seal (Pagophilus groenlandicus, sometimes Phoca groenlandica) of the North Atlantic and Arctic oceans. The adult male is light grayish or yellowish, with brown or black on the head and a similarly coloured U-shaped marking on the back and sides. The female is less clearly marked. Adults are about 6 ft (1.8 m) long and typically weigh between 265 and 300 lbs (120 and 135 kg). Harp seals feed on fish and crustaceans and spend much of the year at sea. They breed near Newfoundland, Can., and in the Greenland and White seas. Until two weeks old, the pups bear a fluffy white coat highly valued by the fur trade; public indignation over hunting methods (including clubbing) has led to increased regulation and supervision of sealing activities in the Newfoundland area.

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Any of nine species of eared seals valued for their fur, especially the chestnut-coloured underfur. Fur seals live in groups and feed on fish and other animals. They were driven nearly to extinction by fur hunters, and most species are now protected by law. The northern fur seal (Callorhinus ursinus) is a migratory inhabitant of northern seas. The male is deep brown, has a grayish mane, grows to about 10 ft (3 m) long, and weighs about 650 lb (300 kg). The dark gray female is much smaller. The eight species of southern fur seals (genus Arctocephalus) occur in the Southern Hemisphere and on Guadalupe Island, Mex. They are brown or black and average 4–6 ft (1.2–1.8 m) long.

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Either of the two largest pinniped species: the northern elephant seal (Mirounga angustirostris), of coastal islands off California and Baja California, or the southern elephant seal (M. leonina), of sub-Antarctic regions. Both are gregarious earless seals. The male has an inflatable, trunklike snout. The northern species is yellowish or gray-brown, the southern species blue-gray. Males of both species reach a length of about 21 ft (6.5 m) and a weight of about 7,780 lbs (3,530 kg) and are much larger than the females. Elephant seals feed on fish and squid or other cephalopods. During the breeding season, bulls fight to establish territories along beaches and to acquire harems of up to 40 cows.

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Small stone cylinder engraved in intaglio on its surface to leave impressions when rolled on wet clay. It first appeared circa 3400–2900 BC and is considered to be one of the finest artistic achievements of Mesopotamia. The earliest examples used geometric or animal patterns; later seals incorporated the owner's name and depicted a variety of motifs. They were used to mark personal property and make documents legally binding. The seals were adopted in Egypt and the Indus civilization.

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Any of about 25 species of herbaceous perennials that make up the genus Polygonatum (lily family), found throughout the Northern Hemisphere. Particularly common in the eastern U.S. and Canada, Solomon's seals flourish in damp, wooded areas and thickets. They have thick, creeping rhizomes and tall, drooping stems, and they bear clusters of white or greenish-white flowers in the axils of leaves, followed by drooping red berries. Similar plants of the genus Smilacina, known as false Solomon's seal, bear their flower clusters at the tips of the stems.

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