Seal (Ang. Sax. seol), an aquatic carnivorous mammal,- the type of the family phocidoe, constituting the old genus phoca (Linn.), which has been variously subdivided. The group of seals is at once distinguishable from other mammals by the structure and arrangement of the limbs; the toes of all the feet are included almost to the end in a common integument, converting them into broad fins, the bones being to a great extent within the skin of the trunk, and the tips armed with strong non-retractile claws; the hind feet are thrown out backward, nearly horizontally, the very short tail being between them, and are the principal agents in swimming and diving; the fore paws when swimming are applied close to the body, and are used only in turning about. The body is cylindrical, tapering gradually backward; the head is small and rounded, and the neck short; the skin has an under woolly down, over which is a covering of long, smooth, and shining hairs, shedding water by an oily secretion, and offer-ing no resistance in swimming; between the skin and muscles is a layer of fat, as in cetaceans, giving that plumpness to the body expressed in the common saying "as fat as a seal." The skull is thin, which renders the head light in the water, in the smaller species without the crests for muscular origins usually seen in carnivora; the face short and broad; zygomatic arches perfect and strong; anterior nasal opening not terminal, and in some directed almost vertically for facilitating respiration when the animal comes to the surface; the tentorium separating the cerebrum and cerebellum is formed wholly from the occipital bone; the orbits are continuous with the temporal fossae, and the skull is very narrow between them, the cranial cavity seeming like a box shut off from the facial portion of the head; the lower part of the occipital bone is broad and thin, with an oval opening in the young in front of the great foramen covered with membrane, but closed by bone in the adults, and the condyles are much larger than in other carnivora; the infraorbital foramina are very large, for the exit of the branch of the fifth pair of nerves, which supplies the sensitive whiskers.; the nasal bones are very short.
The incisor teeth are small and pointed, the canines not generally very projecting. but much worn, and the molars with laterally compressed crowns, sharp cutting edges, many-pointed, and usually single-rooted; the number varies in the different genera. The cervical vertebrae are short, the dorsals and pairs of ribs 15, and the lumbar 5 (in the common seal), the caudals very imperfectly developed, the anterior portion of the sternum prolonged far up the neck and movable, the scapula small with a moderate and nearly central spine, and the coracoid and clavicles absent; the bones of the forearm short, wide, and flattened; the femur at a right angle with the spine and the leg, very short and comparatively immovable, giving greater freedom of motion to the rest of the limb; tibia and fibula long and flat, the former with a double curvature; metatarsal bones and toes long and slender, and the foot wide and paddle-like. The mouth has thick fleshy lips, with many long, knotted, and exceedingly sensitive bristly whiskers with nerves from the fifth pair; the tongue rough and bifurcated at the end; nostrils capable of being completely closed under water; external ears in most merely small valves which close the auditory opening; the eyes (with nictitating membrane) large, full, bright, and expressive of great intelligence; brain large, and with many convolutions; mammae two or four, ventral, near the umbilicus, enclosed in folds of the skin; the intestinal canal is very long for a carnivorous animal; the posterior vena cava, close to the liver, has a large sac or sinus which receives five hepatic veins, serving to retain a portion of the blood from the heart while the animal is under water; the foramen ovale in the heart and the ductus arteriosus are often found pervious; the stomach is elongated, and has a villous coat; the right lung is two-lobed, and the left undivided; the kidneys are divided each into 120 to 140 parts like a bunch of grapes; the testes are permanently retained within the abdomen.
The crystalline lens is more spherical than in land animals, and the sclerotic very thick in front and behind, and thin in the middle, allowing a change of its antero-posterior diameter by compression of the muscles to suit aquatic and aërial vision; the tapetum is remarkably brilliant. They live in the arctic and antarctic seas, near the coasts, and often at the mouth of rivers, preying upon migratory and other fish, crustaceans, and cephalopod mollusks. They are gregarious and migratory, fond of particular spots, leaving the coldest arctic regions in winter for milder seas; the herds are usually of the same species, or when different each species keeps by itself, rarely fighting with the others. Most are polygamous, each male having three or four females, forming small families; gestation lasts nine or ten months, and one or two young are born at a time, which are tenderly cared for; parturition and lactation occupy two or three months, in autumn, winter, or spring, which are passed on shore, the food being such as can be picked up on land or near the coasts, even from the vegetable kingdom; both sexes at this time grow very lean.
They are fond of crawling out of water upon rocks, beaches, and ice floes, for the purpose of basking in the sun, always keeping a good lookout, and plunging into the water at the approach of an enemy; they never go far from their favorite element. They are playful, but at times fight fiercely, as in the breeding season; their bite is severe, and the wounds made by their teeth are not disposed to heal readily either on their own or the human body; some of the larger species are very powerful. The voice is a kind of snapping bark, which, with their canine expression of face, has given them the name of sea dogs. They can remain under water 20 minutes or longer; their animal heat is among the highest found in mammals. They swim with considerable speed, and are most expert divers; their movements on land are awkward and laborious, consisting of a series of short jerking leaps forward by means of the powerful muscles of the back, assisting themselves occasionally, as in climbing rocks and ice, by the anterior limbs; they can advance more rapidly on the ice, by a vertical motion of the spine, somewhat in the manner of a caterpillar, rendered possible by the short spinous processes, large and elastic intervertebral cartilages, and the uncommonly strong spinal muscles.
The senses of smell and sight are very acute. They are easily tamed, affectionate, and docile; at zoölogical gardens they are taught to sit erect, to bow, kiss the hand, pretend to be asleep and to snore, turn the crank of an organ, shoulder a gun, shake hands, and perform other similar simple tricks; in captivity they are much disposed to be drowsy and almost lethargic. Few animals are more tenacious of life than seals, and the most needless cruelties used to be practised in their capture; now the larger species are generally killed at once with the lance thrust into the heart, and the smaller ones are stunned by a blow on the nose from a long-handled hammer, with a sharp spike on the opposite side to hook into the skull. The Esquimaux hunt them in light boats with lances, or spear them at holes in the ice where they come up to breathe; to them the seal supplies food, oil for light and warmth, skins for clothes, boots, utensils, tents, and boats, sinews for thread and lines, and membranes for under garments and window coverings.
The oil is of superior quality, and, if prepared from the fresh animals, is transparent, free from odor, and not unpleasant to the taste; the skin, by a peculiar process of Esquimaux tanning, makes a water-proof leather. - As articles of commerce seal skins are of two kinds, hair skins and fur skins; the former are used for making garments, the latter, now chiefly from Alaska, for finer purposes; all seal skins, however, have a mixture of coarse hairs and finer fur. Millions of skins have been used in Europe and in this country, and thousands of tons of shipping are employed in their capture. Large herds of seals of various species, especially the Greenland and hooded seals, are found on fields of floating ice, called seal meadows; on these the hunters try to surprise them when sleeping, killing the young with clubs and shooting the resisting adults. The seal fishery is extensively carried on from Newfoundland, in sailing vessels of from 50 to 200 tons burden, each manned by from 25 to 90 men; recently steamers have also been employed, ranging from 175 to 450 tons, with from 100 to 200 men each.
The seals are taken on the ice off the E. and N. coasts of. the island; the season lasts from the first of March to the close of May. The principal species taken are the harp and hooded seals, chiefly the former; two other varieties are also taken in Newfoundland, the square-flipper seal, a large species, and the dotard or native seal, which never leaves the island; the skins of the latter are more valuable than those of the other species, being spotted, and are much used for trunk covers, coats, gloves, etc. The fishery was not prosecuted by Newfoundlanders prior to 1763; in 1787 4,900 seals were taken from the ice, and the oil extracted; in 1871 there were 201 sailing vessels and 13 steamers employed, with an aggregate crew of 9,791 men; the number of steamers is increasing. The exports of seal skins from Newfoundland between 1838 and 1848 varied from 400,000 to nearly 700,000 annually; for the exports of oil and skins from 1868 to 1872 inclusive, see Fisheries, vol. vii., p. 234. (See also Newfoundland.) Many seals are taken in early spring at the Magdalen islands and on the Labrador coast among the floating ice, and also by nets set across narrow channels.
Besides man, the seal has to guard against bears on land and on the ice, and against sharks and carnivorous cetaceans in the water. - In the genus phoca, as restricted by modern naturalists, the dental formula is: incisors 6/4, canines (1-1)/(1-1), and molars (5-5)/(4-4) = 32; the molars have three or four triangular cusps, all except the first with double roots, and placed obliquely along the jaw; the posterior margin of the palate is acutely and deeply notched, and the palatal foramen is on the maxillary bone. The group to which the common seal belongs was named callocephalus by F. Cuvier, on account of the fine shape and large size of the cranium and the shortness of the face; the brain is nearly as large as that of the most intelligent monkeys. This species - the P. (C.) vitulina (Linn.), the phoque commun and veau marin of the French, the Seehund of the Germans - attains a length of 4 to 6 ft.; the color varies much, but is generally brownish above and yellowish white below, variously mottled, and sometimes pied and marbled.
It is common in the European seas, especially those washing the northern countries; it is fattest in spring; a single large animal will yield from 8 to 12 gallons of oil excellent for lamps; the leather is used for boots, and the hide for caps, trunk covers, etc.; the matter which lubricates the hair has a penetrating and offensive odor. Along the New Brunswick coast this species, which is called there the harbor seal, is often seen in summer; the fur is very handsome, and is highly prized by the Micmac Indians; it is also common all along the New England shore. The Greenland or harp seal (P. [C] Groen-landica, Müll.) is about 6 ft. long; the males are grayish white, with the face and a broad lunate mark on the back and sides black; the females are brownish with blackish spots, and the young snow-white; the molars are in a straight line, with a small interval between them and the anterior tubercle obsolete; the posterior margin of the palate almost directly transverse. They are found in herds on the coast of Greenland on floating ice, rarely venturing on shore or shore ice; they are sometimes floated to the coasts of Great Britain, and are not uncommon on those of.
Labrador and Newfoundland. This is the most important of all to the Esquimaux, who harpoon it from their kaiaks; the oil is the best and most abundant in this species, and the skins form an important article in the fur trade. The young are born in spring. A species of seal (P. Cas-pica, Pall.), about the size of the common seal, occurs in the Caspian sea, the sea of Aral, and Lake Baikal; it affords an excellent oil, to obtain which many thousands are annually killed. - In the narrow-muzzled seals belongs the genus 8tenorhynchus (F. Cuv.), with the incisors 4/4, pointed, and the molars (5-5)/(5-5), divided into three to five long points, conical, somewhat hooked, and usually two-rooted; the snout is long and narrow, and the claws, especially on the hind feet, very small, hence called leptonyx by Wagner and Gray. The leopard seal or sea leopard (S. Weddellii, Less.; L. leopardinus, Wagn.) is 9 or 10 ft. long, spotted above somewhat as a leopard, whitish on a grayish brown ground, and yellowish below; the head is long and small, the neck long and tapering, and the hair soft and thin; it frequents the frozen seas of the southern hemisphere, about the South Shetland and South Orkney islands.
In the genus pelagius (F. Cuv.) the snout is broad and long; the number of teeth is the same as in the last genus, but the incisors are indented and shut into each other, and the molars are thick, compressed toward the crown, with rudimentary points and central conical cusp. The white-bellied or monk seal (P. mo-nachus, F. Cuv.) grows to a length of 8 or 10 ft.; it is shining dark brown above, spotted with gray on the neck and head, and the lower parts and portions of the sides white; eyes large and ox-like; it is gentle, easily tamed, intelligent, and affectionate; it is found in the Adriatic sea and on the coast of Sardinia, and was the one best known to the ancients; its skin was believed by the old Romans to be a preservative against lightning, and tents were made of it under which they took refuge in thunder storms. - In the genus stemmatopus (F. Cuv.) or cystophora (Nilss.), the incisors are 4/2 and conical, the canines large, and the molars (5-5)/(5-5), simple-rooted, compressed and striated, with three lobes and many small indentations; the generic name is derived from a soft crownlike appendage from the nose to the back of the head.
The hooded or crested seal (P. leo-nina, Fabr.; S. cristatus, F. Cuv.) attains a length of 7 or 8 ft.; the color is dark brown above with gray spots, the young being light-colored; they have on the head a membranous and muscular sac covered with hair, divided into chambers by a prolongation of the nasal septum; when the nostrils are closed this can be inflated with air; the skins are among the most common in the market. They are fond of the ice islands of high northern latitudes, coming down to the coast of Labrador; they are polygamous, fierce when wounded, and fight furiously with each other. The appendage on the head may be, as the fishermen suppose, a reservoir of air for use during submersion, or an accessory to the organ of smell, as its vascular nature seems to indicate. - In macrorhi-nus (F. Cuv.) the incisors are far apart, hooked like small canines, the central ones the smallest; the canines are strong tusks; the molars have simple roots, the crowns appearing like nipples on a rounded base; the number of teeth is the same as in the preceding genus; the forehead is very prominent, the bones as in the elephant for supporting a trunk; the nasal bones are very short, and the maxillaries long with a very large nasal opening between them.
The bottle-nosed seal or sea elephant (M. [morunga, Gray] proboscideus, F. Cuv.) is the largest of the seal family, attaining a length of 25 ft. or more, with a circumference of about 16 ft., the size as well as the proboscis justifying the popular name. The males are generally dark grayish blue or brown; they can elongate the muzzle to a foot in length; the females are dark olive-brown above and yellowish below, and do not have the nasal appendage; they are polygamous, and the males in the breeding season are very pugnacious; they have four fingers and a short thumb on the fore limbs with perfect nails, and the hind toes nailless. The hair is rather coarse, but the thick skin is in much request for harnesses; a single animal will yield 14 to 15 bbls. of blubber, from which the oil is obtained as in the whale; the oil is clear, without bad odor or taste, and burns slowly and without smoke; in England it is used for softening wool and in the manufacture of cloth; the salted tongues are esteemed as food. They are found in large herds on the shores of the islands of the antarctic seas, going north in winter to the coasts of Patagonia, remaining between lat. 35° and 55° S.; they prefer sandy and desert beaches, in the neighborhood of fresh water, in which they like, to wallow.
They never attack man unless brutally treated by him; from indiscriminate slaughter they are now very scarce in their former accessible haunts. This species is half as large as the Greenland whale, and very much larger than the largest elephant. - The family of otariadoe or eared seals is very distinct from that of the phocidoe. Dr. T. Gill, in his "Monograph of the Pinnipeds" (1856), first introduced some order into the confused nomenclature and characters of these seals; and after him J. A. Allen, in the "Bulletin of the Museum of Comparative Zoology" (vol. ii., No. 1, 1870), gave special attention to the family. Mr. Allen divides them into trichophocinoe or hair seals, with the genera otaria, eumetopias, and za-lophus, and oulophocinoe or fur seals, with the genera arctocephalus and callorhinus. In the otariadoe, which includes the sea lions and sea bears, the incisors are 6/4, the four upper middle ones with broad crown divided by a transverse groove, the outer two conical; molars (6-6)/(5-5), sometimes with one less above; the fore feet are further back than in the other seals; the hind feet have the membrane prolonged beyond the nails into long straps or ribbons; the fore feet are nailless, and the lower surface of all the limbs is without hair; there are also small external ears, from which these seals are called otaries.
The name of sea lion has been given to a number of large seals of both hemispheres, either from their savage appearance, roaring voice, powerful canines, or maned neck. The northern or Steller's sea lion (eumetopias Stelleri, Peters) is about 15 ft. long, with a weight of about 1,600 lbs.; the males have stiff curled hair on the neck, a thick hide, coarse tawny reddish hair, and a mane of erect hair; the head is large, the nose long and truncated, the eyebrows bushy, and the ears distinct. They are found on the E. shores of Kamtchatka, about the Kurile islands, and the N. W. coast of America, on rugged shores and desert rocks in the ocean; their food consists of fish, the smaller seals, sea otters, and marine birds and animals. The southern sea lion (0. jubata, De Blainv.) is of about the same size and general appearance as the last, with similar habits, is heavy and clumsy in its gait, and fears man; it is found in the south seas, sometimes coming to the Patagonian coasts; it is rarely hunted except by savages, though the oil is excellent. The name of sea bear has been applied to many smaller seals of both hemispheres, with a less ferocious aspect but fiercer disposition than the sea lions.
The northern ursine seal or sea bear (callorhinus ursinus, Gray) is about the size of a large bear, between 7 and 8 ft. in length; the forehead is much arched, the lips tumid, and the ears nearly 2 in. high; close to the skin is a soft reddish wool, over which is a dark coarse hair; the females and young are ashy. It is very fat in spring before the young are born; it is polygamous, the males tender to the young but tyrannical to the females; if wounded, it will attack a boat, and is very tenacious of life; it is the terror of the smaller seals and sea otters, and is itself afraid of the sea lion. This species furnishes the greater portion of the fur seal skins of commerce. It is found chiefly on the Pribyloff islands in Behring sea, a group belonging to Alaska, collecting especially on St. Paul's and St. George's islands. The "rookeries" contain several millions of seals; the adult males begin to arrive about the first of May (the great body about the first of June) and the females about the middle of June, giving birth to their young soon after landing; the "bachelor" seals, as males under six years old are called, do not collect on the "rookeries," but have separate "hauling grounds;" nearly all leave the islands about the end of October or middle of November. The males on the "rookeries" do not go into the water from the time of "hauling up" in May till after the first of August, being sustained in the mean time by the absorption of their own fat.
After leaving the islands in autumn, the seals spread out over the North Pacific, following schools of fish, or frequenting shoals and banks where cod are abundant; at this time they are shy and difficult to approach, unless asleep, in which condition they are captured by the natives all along the N. W. coast from the Columbia river to Behring sea; in spring they return to the breeding grounds on the islands. The capture of the seals for their fur begins with their first landing on the islands, and may continue till they begin shedding their fur in August or September; they are killed by the natives with clubs; only the "bachelor" seals are allowed to be captured. The blubber of the fur seal is of a faint yellowish white, and lies entirely between the skin and flesh; it possesses an odor exceedingly offensive, and difficult to wash from the hands. The flesh, when carefully cleaned of fat, can be eaten; it resembles poor, tough, overdone beef. (See Fur, vol. vii., pp. 536 and 538.) The southern sea bear (arctocephalus Falklandicus, Gray) is smaller than the last, to which it is similar in habits, but larger than the common seal, the males being about 7 ft. long, and the females considerably smaller; the hair is of different colors, black, brownish, gray, and variously spotted with grayish and yellowish, and the under fur is short and fine.
It was formerly very abundant about the islands of the , southern ocean, especially the Falkland, but is now almost extirpated. Some thousands of skins have recently been obtained, however, at the South Shetland islands by vessels from New London, and there is a small rookery on the Lobos islands protected by the Argentine government. It was from this species that the market was formerly supplied. - A few fossil remains of species nearly allied to the common and monk seals have been found in the upper tertiary formations of Europe and North America, and recently in the Yorktown (miocene) strata of the Atlantic coast, with those of the whale, dolphin, and walrus. - See "The Seal and Herring Fisheries of Newfoundland," by Michael Carroll (Montreal, 1873), and "The Marine Mammals of the Northwestern Coast of North America," by Charles M. Scammon (4to, New York, 1874).
Common Seal (Phoca vitulina).
Greenland Seal (Phoca Groenlandica).
Hooded Seal (Stemmatopus cristatus).
Southern Sea Lion (Otaria jubata).
Sea Bear (Callorhinus ursinus).