seal

seal¹

—sealable, adj.

/seel/, n.

1. 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. set one's seal to, to give one's approval to; authorize; endorse: Both families have set their seal to the marriage.

13. the seals, Brit. the tokens or signs of public office.

v.t.

14. to affix a seal to in authorization, testimony, etc.

15. to assure, confirm, or bind with or as if with a seal: They sealed the bargain with a handshake.

16. to impress a seal upon as evidence of legal or standard exactness, measure, quality, etc.

17. to close by any form of fastening that must be broken before access can be gained.

18. to fasten or close tightly by or as if by a seal: She was sealing envelopes. My lips are sealed.

19. to decide irrevocably: to seal someone's fate.

20. to grant under one's seal or authority, as a pardon.

21. Mormon Ch. to make (a marriage or adoption) forever binding; solemnize.

22. Elect. to bring (a plug and jack or socket) into locked or fully aligned position.

23. 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.

[1175-1225; (n.) ME seel, seil(e), seale mark on a document, token < OF seel (F sceau) < LL *sigellum, L sigillum, dim. of signum SIGN; r. ME seil, OE (in)segel seal < LL, as above; (v.) sealen, seilen < OF seeler, seieler, deriv. of seel]

seal²

—seallike, adj.

/seel/, n., pl. seals, (esp. collectively for 1) seal, v.

n.

1. 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.

2. the skin of such an animal.

3. leather made from this skin.

4. the fur of the fur seal; sealskin.

5. a fur used as a substitute for sealskin.

6. a dark, gray brown.

v.i.

7. to hunt, kill, or capture seals.

[bef. 900; ME sele, OE seolh; c. ON selr]

seal³

/seel/, v.t. Falconry.

seel (def. 1).

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I

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.

II

(as used in expressions)

cylinder seal

elephant seal

fur seal

harbour seal

harp seal

leopard seal

oil seal

shaft seal

Solomon's seal

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      in documentation, an impression made by the impact of a hard engraved surface on a softer material such as wax or clay, producing a device in relief. Seals have been used from remote antiquity to authenticate documents. The study of seals, known as sigillography (q.v.), is a major historical discipline.

▪ mammal

Introduction

  any of 32 species of web-footed aquatic mammals that live chiefly in cold seas and whose body shape, round at the middle and tapered at the ends, is adapted to swift and graceful swimming. There are two types of seals: the earless, or true, seals (family Phocidae); and the eared seals (family Otariidae), which comprise the sea lions and fur seals. In addition to the presence of external ears, eared seals have longer flippers than do earless seals. Also, the fur of eared seals is more apparent, especially in sea lions.

 Seals are carnivores, eating mainly fish, though some also consume squid, other mollusks, and crustaceans. Unlike other seals, the leopard seal (Hydrurga leptonyx) of the Antarctic feeds largely on penguins, seabirds, and other seals, in addition to fish and krill. The main predators of seals are killer whales, polar bears, leopard seals, large sharks, and human beings.

Seal diversity

 The Baikal seal (Phoca sibirica) of Lake Baikal in Siberia, Russia, is the smallest at 1.1–1.4 metres (3.6–4.6 feet) long and 50–130 kg (110–290 pounds), but some female fur seals weigh less. The largest is the male elephant seal (genus Mirounga leonina) of coastal California (including Baja California, Mexico) and South America, which can reach a length of 6.5 metres (21 feet) and a weight of 3,700 kg (8,150 pounds). The upper portions of seals' limbs are within the body, but the long feet and digits remain, having evolved into flippers. Seals possess a thick layer of fat (blubber) below the skin, which provides insulation, acts as a food reserve, and contributes to buoyancy.

 True seals of the genus Phoca are the most abundant in the Northern Hemisphere. They are fairly small, with little difference in size between the sexes. ringed seals (P. hispida) have blotches over their entire bodies, harp seals (P. groenlandica) have a large blotch of black on otherwise mostly silver-gray fur, harbour seals (P. vitulina) have a marbled coat, and ribbon seals (P. fasciata) have dark fur with ribbons of paler fur around the neck, front limbs, and posterior part of their body.

      Though especially abundant in polar seas, seals are found throughout the world, with some species favouring the open ocean and others inhabiting coastal waters or spending time on islands, shores, or ice floes. The coastal species are generally sedentary, but the oceangoing species make extended, regular migrations. All are excellent swimmers and divers—especially the Weddell seal (Leptonychotes weddellii) of the Antarctic. Various species are able to reach depths of 150–250 metres or more and can remain underwater for 20–30 minutes, with the Weddell seal diving for up to 73 minutes and up to 600 metres. Seals cannot swim as fast as dolphins or whales but are more agile in the water. When swimming, a true seal uses its forelimbs to maneuver in the water, propelling its body forward with side-to-side strokes of its hind limbs. Because the hind flippers cannot be moved forward, these seals propel themselves on land by wriggling on their bellies or pulling themselves forward with their front limbs. Eared seals, on the other hand, rely mainly on a rowing motion of their front flippers for propulsion. Because they are able to turn their hind flippers forward, they can use all four limbs when moving on land.

 All seals must come ashore once a year to breed. Nearly all are gregarious, at least when breeding, with some assembling in enormous herds on beaches or floating ice. Most form pairs during the breeding season, but in some species, such as fur seals, the gray seal (Halichoerus grypus), and elephant seals, males (bulls) take possession of harems of cows and drive rival bulls away from their territory. Gestation periods average about 11 months, including a delayed implantation of the fertilized egg in many species. Cows are again impregnated soon after giving birth. Pups are born on the open ice or in a snow lair on the ice. The mother remains out of the water and does not feed while nursing the pups. The young gain weight rapidly, for the cow's milk is up to about 50 percent fat.

      Seals have been hunted for their meat, hides, oil, and fur. The pups of harp seals, for example, are born with white coats that are of value in the fur trade. The fur seals of the North Pacific Ocean and the ringed seals of the North Atlantic Ocean have also been hunted for their pelts. Elephant seals and monk seals were hunted for their blubber, which had various commercial uses. Seal hunting, or sealing, was so widespread and indiscriminate in the 19th century that many species might have become extinct if international regulations had not been enacted for their protection. The severe decline of sealing worldwide after World War II and the effects of international agreements aimed at conserving breeding stocks enabled several severely depleted species to replenish their numbers.

Classification

Seals

 32 species belonging to 17 genera in 2 families. Together with walruses, seals and sea lions are classified as pinnipeds (suborder Pinnipedia).

      Family Phocidae (true, or earless, seals)

 18 species in 10 genera.

      Genus Phoca (common seals)

 7 species of the Northern Hemisphere: the Baikal seal, Caspian seal, harbour seal, harp seal, ribbon seal, ringed seal, and spotted seal.

      Genus Monachus ( monk seals)

 2 species of the Mediterranean Sea and Hawaii. A third, the Caribbean monk seal, became extinct in the latter half of the 20th century.

      Genus Mirounga ( elephant seals)

 2 coastal species, one from the Southern Hemisphere, one from the Baja California Peninsula to southeastern Alaska.

      Genus Cystophora ( hooded seal)

 1 North Atlantic Ocean and Arctic species.

      Genus Erignathus ( bearded seal)

 1 Arctic species.

      Genus Halichoerus ( gray seal)

 1 North Atlantic Ocean species.

      Genus Hydrurga ( leopard seal)

 1 Antarctic species.

      Genus Leptonychotes ( Weddell seal)

 1 Antarctic species.

      Genus Lobodon ( crabeater seal)

 1 Antarctic species.

      Genus Ommatophoca ( Ross seal)

 1 Antarctic species.

      Family Otariidae (eared seals)

 14 species of sea lions and fur seals in 7 genera.

      Genus Arctocephalus (southern fur seals)

 8 species, primarily of the Southern Hemisphere.

      Genus Callorhinus (northern fur seal)

 1 species of the North Pacific Ocean.

      Genus Eumetopias (Steller sea lion)

 1 species of the North Pacific Ocean.

      Genus Neophoca (Australian sea lion)

 1 species of Australia.

      Genus Otaria (South American sea lion)

 1 species primarily of western South America.

      Genus Phocarctos (New Zealand sea lion)

 1 species of New Zealand.

      Genus Zalophus (California sea lion)

 1 species of the North Pacific Ocean.

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