any of numerous marine carnivores of the suborder Pinnipedia, including the eared or fur seals, as the sea lion, and the earless or hair seals, as the harbor seal.
an embossed emblem, figure, symbol, word, letter, etc., used as attestation or evidence of authenticity.
2.
a stamp, medallion, ring, etc., engraved with such a device, for impressing paper, wax, lead, or the like: The king took the seal from his finger and applied it to the document.
3.
the impression so obtained: It was unmistakably the royal seal on the document.
4.
a mark or symbol attached to a legal document and imparting a formal character to it, originally wax with an impression.
5.
a piece of wax or similar adhesive substance so attached to an envelope, folded document, etc., that it must be broken when the object is opened, insuring that the contents have not been tampered with or altered.
6.
anything that tightly or completely closes or secures a thing, as closures or fastenings for doors and railroad cars, adhesive stamps and tapes used to secure the flap of an envelope, etc.
7.
something that keeps a thing secret: Her vow was the seal that kept her silent.
8.
a decorative stamp, esp. as given to contributors to a charitable fund: a Christmas seal.
9.
a mark, sign, symbol, or the like, serving as visible evidence of something.
10.
anything that serves as assurance, confirmation, or bond: She gave the plan her seal of approval.
11.
Plumbing.
a.
a small amount of water held by a trap to exclude foul gases from a sewer or the like.
b.
the depth of the part of the water that actually excludes the gases.
12.
the seals, British. the tokens or signs of public office.
–verb (used with object)
13.
to affix a seal to in authorization, testimony, etc.
14.
to assure, confirm, or bind with or as if with a seal: They sealed the bargain with a handshake.
15.
to impress a seal upon as evidence of legal or standard exactness, measure, quality, etc.
16.
to close by any form of fastening that must be broken before access can be gained.
17.
to fasten or close tightly by or as if by a seal: She was sealing envelopes. My lips are sealed.
18.
to decide irrevocably: to seal someone's fate.
19.
to grant under one's seal or authority, as a pardon.
20.
Mormon Church. to make (a marriage or adoption) forever binding; solemnize.
21.
Electricity. to bring (a plug and jack or socket) into locked or fully aligned position.
—Verb phrase
22.
seal off,
a.
to close hermetically: to seal off a jar.
b.
to block (an entrance, area, etc.) completely so as to prevent escape or entrance: The police sealed off the area after the bomb threat was received.
—Idiom
23.
set one's seal to, to give one's approval to; authorize; endorse: Both families have set their seal to the marriage.
[Origin: 1175–1225; (n.) ME seel,seil(e), seale mark on a document, token < OF seel (F sceau) < LL *sigellum, L sigillum, dim. of signumsign; r. ME seil, OE (in)segel seal < LL, as above; (v.) sealen, seilen < OF seeler, seieler, deriv. of seel]
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.
Bibliography
See B. Davies, Savage Luxury: The Slaughter of the Baby Seals (1971); V. B. Scheffer, The Year of the Seal (1972); J. E. King, Seals of the World (2d ed. 1983); R. L. Gentry and E. L. Kooyman, Fur Seals (1986).
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