CAMELS, DEER, GIRAFFES AND PRONGHORNS
This is a rather miscellaneous group introducing the typical Herbivora. The most ancient of them in the style of their structure are certain little spotted creatures, like miniature deer in appearance, that inhabit the forests of western Africa and the Orient, and are known as chevrotains. The fact that in their metapodial bones they resemble the structure of camels causes these apparently so distant animals to be placed next to camels in classification.
The history of the camels (Camelidæ) is very similar to that of the horse. The family originated in North America, where it developed from little creatures, by changes and adaptations to a life on dry uplands, as did the horses, into a species which in the Pleistocene was a third larger than any now living. Meanwhile camels had made their way over the land which in the later Tertiary connected Alaska with Siberia, into the high plains of Asia, where the camels found favorable circumstances and developed into the two species we know. Others migrated, earlier in the family history, into South America, where they ceased to grow tall after the camel model, but became the huanacos of Patagonia, of which the llamas (yah-mas) are prehistorically domesticated descendants, and into the woolly vicuñas of the Andean mountains.
| LLAMA |
| (Lama peruviana) |
| A domesticated animal of South America |
Modern camels are of two kinds—the single-humped and the double-humped. The latter, or "Bactrian," is confined to Asia, and is able to endure the cold and snows of the tablelands of that continent, where its burdens are carried in winter as well as summer. What was the extent to which the single-humped, or ordinary camel, ranged before its prehistoric enslavement by men, we do not know—if it roamed the deserts of Arabia and northern Africa as well as those of Turkestan, no evidence of it remains. A few small-sized, gaunt, wary, and swift-footed camels still run wild among the almost inaccessible sand dunes of the Gobi Desert, but it is not certain that they are relics of the original wild stock. At any rate the camels have always been creatures of the world's waste places, and all their quaint peculiarities such as their sole pads and the water-storing sacs in their stomachs (rumens) are adaptations to their desert home.
| BACTRIAN CAMEL |
| (Camelus bactrianus) |
| The two-humped camel of Asia |
The deer family (Cervidæ) is of great extent, and world-wide in its distribution, except that it is entirely absent from Africa and Australia. In none are more than two toes of use in walking, the second and fifth toes hanging at some distance behind and above the functional hoofs, which are narrow and pointed. All have slender, long legs, giving swiftness and great leaping power; and very short tails, with the exception of the rare and peculiar David's deer of China, whose tail is almost like that of a cow. The coat of hair is short and brittle, reddish brown or foxy in summer, grayer in winter, in some species plain, or spotted only when fawns, in others variegated with small, whitish spots. The distinctive badge of the family, however, is the pair of horns borne on the heads of the males (also by females in the reindeer and caribou), collectively and more properly called "antlers," since they are not composed of horn, but of true bony material. They are poised on two protuberances on the top of the skull, where in spring arises a growth of fleshy material, covered with velvety hair, that rapidly takes the shape of the antler characteristic of the species (and age) of the deer, and as it grows is filled with lime salts that gradually replace all the tissues. Then the "velvet" dries and scales off and the ivorylike antler emerges. This remains as a serviceable weapon and ornament of the buck until the beginning of winter, when its attachment to the skull loosens, and the antler drops off. This happens annually in the case of all deer—one of the common and universal facts in zoölogy that many find it hard to believe. The "horns" of the various deer vary in size from short and simple "spikes" to the wide-branching antlers of the moose and wapiti; but these last are acquired only when the buck is fully matured, the yearling showing only a spike, and acquiring branches ("tines") one by one annually as he grows until his proper complement is reached; but in a few small species no branching ever occurs.
The family contains many genera and species, but only the most noticeable can be mentioned. The most familiar one, probably, is the small, spotted fallow deer of southern Europe, bands of which ornament the parks of grand estates in Great Britain and on the continent; its antlers broaden at the end into the form known as "palmated," on account of its resemblance to an open hand with fingers. Even more celebrated in song and story is the red deer, the males of which are "stags" and the females "hinds." These are large, dark, reddish brown animals, with grandly symmetrical antlers, every tine or "point" on which—seven on each side in a "full head"—has its name in the language of hunting. This deer, still wild in the highlands of Scotland and in the mountainous forests of eastern Europe, is also to be found right across Asia, where local varieties go by the names of "maral" in northern Persia, "hangul" in Kashmir, and so on to eastern Siberia, where far taller species live than are known to Europe; and all vary in minor particulars only from our wapiti—which it is fair to regard as of the same stock.
None of all these stags is more stately than the American wapiti—the "elk" of all western men—which once abounded from the Adirondacks and southern Alleghenies to California and the borders of Alaska. Everywhere of old it was plentiful and easy to kill, and the pioneers swiftly destroyed it as civilization was pushed westward, until its mighty herds have vanished almost as completely as those of the bison. It thrived anywhere and everywhere, climbing the wooded heights of the Appalachians (where the very last one was killed near Ridgway, Pennsylvania, in 1869), loafing in the warm, well-watered valleys of the Mississippi basin, herding in the sun-baked plains, or scrambling up and down the roughest of western sierras. Equally broad in its appetite, those that browsed or ate mast and fruits in the eastern woods did no better than those which grazed on the bunch-grass plateaus from the Rio Grande to Peace River; and in winter it would keep fat where other deer or cattle might starve, because able to paw through the snow to the dried grass.
The other round-horned deer of the United States are the familiar Virginian, white-tailed, or willow deer, which is to be found all over the country, and in similar species in Mexico and Central America; the larger black-tailed, long-eared "mule deer," or "jumping deer," of the plains and the foothills of the Rocky Mountain region, and the small, forest-keeping, black-tail, or Columbian deer of Oregon and northward.
Canada, Alaska, and the northern parts of Maine and Minnesota, are the refuge of that biggest of all the deer, which we call by the Indian name "moose," but which is known to Europeans as "elk," for it is a circumpolar species that once roamed in great numbers through the woods of all Europe, and in this country far southward along the Appalachians. Until the World War the elk was preserved in certain large forests of Lithuania and central Russia, but it is doubtful if any survived the desolation of that region during and after the war. The moose is everywhere a forest-ranging animal, especially fond of regions where rivers and lakes abound, in which it finds desirable food in summer and takes much pleasure; yet in the mountainous West it often climbs to high and dry heights. Its principal diet is leaves and twigs, pulled off by the long, flexible lips that are so characteristic a feature. The moose is a huge, immensely strong and ungainly animal, blackish brown with pale legs and belly, and with a neck so short that it can graze only by kneeling. A very large bull may stand six and a half to seven feet high at the withers, which, with the neck, are clothed in a thick mantle of long, coarse, stiff hair; and from the throat hangs a long hairy strip of dew-lap skin (the "bell"), which in old age draws up into a sort of pouch. The long and narrow head ends in an overhanging, flexible muzzle, that may be curled around a twig like a proboscis. On this massive head and neck the bulls carry a wonderful pair of flattened antlers, always surprisingly wide in spread, but varying greatly in weight, and that irrespective of the relative bigness of the animal. The moose of the Kenai Peninsula, Alaska, are famous for the immensity and complication of their horns; one pair preserved in the Field Columbian Museum, Chicago, have a spread of seventy-eight and a half inches, show thirty-four points, measure fifteen inches around the burr, and with the dry skull weigh ninety-three pounds; but very few reach such dimensions.
| REINDEER CROSSING A STREAM |
| From a prehistoric engraving on an antler found in southern France |
Another flat-horned deer is the famous reindeer of the boreal regions of both hemispheres, for our arctic caribou are the same animals under another name. No truly wild reindeer now exist in the Old World, but they are scattered over all the Barren Grounds, or treeless coast areas and islands, from Greenland to Alaska; and the Eskimos depend on them not only for food to some extent, but even more for clothing and tentage. Every autumn enormous herds of these caribou, gathered in migration, sweep southward to less frigid and snowy feeding grounds in the region between Hudson Bay and Great Slave Lake, and there enable the Indians to provide themselves with meat and skins for the winter. These arctic caribou feed mainly on the lichen called "reindeer moss." Another kind, the "woodland" caribou, inhabits the uncivilized forest borders south of the Barren Grounds, and the mountain region from British Columbia to the arctic shore of Alaska and Yukon; and in the east occurs in Ungava, Labrador, Newfoundland, and New Brunswick. They are not regularly migratory, but wander in small herds, prefer swampy woods, and their habits approach those of the moose. There is no great difference otherwise between them and the arctic caribou; but they vary a good deal, so that several species have been named among those of the west, one of which, in Alaska, is quite white.
Southeastern Asia has many kinds of deer, such as the large staglike sambar of India and eastward; the spotted axis, or chital; the sika of Japan; and a variety of small Oriental species exist.
| OKAPI |
| (Okapia johnstoni) |
| A relative of the giraffe, found in the forests of Africa |
The giraffes of equatorial Africa (family Giraffidæ) are closely related to the deer. They are hornless, but from the top of the skull project two protuberances, several inches in length, which answer to the horn-cores of the deer, but carry no antlers, and are permanently covered with hairy skin; between them is a third shorter protuberance of the skull. A few years ago it was discovered that there existed in the dense forests of the lower Congo valley an animal of this family, but smaller and more antelopelike in body, and without the towering characteristics of the giraffe, called by the Pygmies of that district "okapi" or "o'api." It is chestnut in color, with yellowish cheeks and the legs marked with wavy, whitish stripes. It is perhaps not rare, but is exceedingly difficult to obtain in the dense jungle it inhabits.
Two singular animals remain to be mentioned here, as standing intermediate between the deer and the cattle family, next to be considered. One of these is the musk deer of the Himalayas, from which is taken the "pod," or ventral gland, that contains the odorous substance "musk." This is a strange, old-fashioned, solitary little creature, the size of a half-grown kid, and having very large ears, almost no tail, and no horns, but wearing a pair of keen weapons in the long upper canines which hang well down below the lower jaw. The four toes of the feet are almost equal, and the hoofs so free that they can fairly grasp any projection, so that the animal is a marvel of agility and surefootedness.
Our American pronghorn "antelope" is the second of these intermediate animals, and is not far removed in its structure from our white mountain goat. It foreshadows the sheathed-horned ruminants, but differs from all of them in the fact that its horns bear a prong, and also in that they are periodically shed and renewed. This beautiful and graceful little animal, truly antelopelike in form and habit, stands about three feet high at the shoulder, has slender legs and feet, with no false hoofs, and is exceedingly swift in its bounding gait. It is now almost gone from the wide plains where only a few years ago it was to be seen in summer from the Saskatchewan to the Rio Grande and southward. In the autumn it would gather in the North into ever-increasing herds that swept southward to pass the winter in Texas and New Mexico, and then would return northward with the advance of spring. The extension of fenced ranching, but most of all the spanning of the plains by railroads, rapidly put an end to these migrations, and the wasteful killing of the pronghorns in sport, or as food, completed the virtual extermination of one of the most interesting and desirable animals of the New World.
[CHAPTER XXXII]
SOME SUPREMELY USEFUL ANIMALS
The fact that likeness of structure, which compels naturalists to group certain animals into a family in spite of possible unlikeness in size or form, is accompanied by resemblance in quality, is well illustrated by the family Bovidæ (Latin boves, "cattle") which includes goats, sheep, antelopes, and oxen; for all of these in flesh, products and disposition, are alike suited to the requirements of men, and especially of mankind in a social civilization. This family of animals furnishes us with nearly all of our milk, butter, and cheese; with flesh food, woolen clothing, leather goods, horn, gelatin, etc.: and gives us such servants as the ox and goat; while sportsmen find in it the most fascinating of their larger game.
The distinctive feature of this most useful of animal tribes is the possession of hollow horns, properly so called. Horn is a chitinous material developed from the skin, and not dissimilar to hair; indeed it would be no great stretch of facts to say that a cow's horn was composed of agglutinated hairs. These horns are sheaths that grow over cores of bone—outgrowths of the skull—increase in size until their wearers are mature, grow at the base as fast as worn at the tips, and are never shed. They may be borne by the males alone, or by both sexes; or the males may have horns far larger than those of the female, as in the sheep; and in a few cases both sexes are hornless. No family is more difficult to subdivide, for the various forms intergrade inextricably.
Our mountain goat, or "mazama," which dwells on the snowy heights of the Pacific Coast ranges, from southern British Columbia to farthest Alaska, is one of these intermediate ones, suggesting both goat and antelope in its make-up. It is about the size of an ordinary domestic goat, has small, sharp, black horns, and is clothed in long white hair with an undercoat of wool fitting it for the wintry cold in which its life is spent, for except in midwinter it never comes below timber line, and even then avoids the wooded places. In the rough mountains of Japan lives a similar goat antelope, woolly, but not white; and the lofty heights of western China is the home of a smaller one, the goral, and the Himalayas have the big serow. All these have short, sharp horns rising from the top of the skull. Their nearest western neighbor is the famous chamois of the Alps and Carpathians of Europe. The extraordinary agility of these mountaineers is possible because of the pads beneath their hoofs that give them the clinging surefootedness which is so remarkable.
Most closely allied to them, probably, are the goats, also denizens of mountain regions, the typical species being confined to the highlands between the Caucasus and northwestern India. This is the true goat from which the domestic goat is descended; but the long-haired "Angora" goat is derived from the markhor, a sheeplike animal of the Himalayas with tall, much twisted horns. One of the special characteristics of the goats (genus Capra) is the beard of the rams; and this feature belongs also to the ibexes, several similar species of which are found from the Pyrenees eastward along the mountain tops to northern China, each occupying a limited section of country, and one inhabiting the mountains about the head of the Red Sea. That of Spain is called "bouquetin," and that of the Alps "steinbok." All the rams possess great horns, sometimes fifty inches long, that rise from the occiput, curve backward, and show on their fronts a series of prominent cross ridges. One passes from these goats to their near relatives, the sheep, by way of the "bharal" (or "burrel") which combines the characteristics of the two sections so thoroughly that the proverbial "separating the sheep from the goats," easy enough on the farm, is practically impossible among wild flocks. In this crag-loving wanderer the horns of the rams are as long as those of an ibex, but roundish and wide spreading, instead of upright and cross-ridged. The "aoudad," whose home is in the mountains of Morocco and Algiers, and which is familiar in menageries, has such horns, but approaches nearer in other respects to the typical sheep, whose rams carry the great spiral horns at the side of the head, that are still the pride of our domestic merinos, and were the badge of the Theban god of gods, Ra Ammon. No better example of these magnificent mountaineers, which under one or another of several specific and local names, such as argali, oorial, etc., are, or were, to be found on rough highlands all the way from the Mediterranean to Bering Sea, can be shown than our own "bighorn" sheep of the Rocky Mountains, and of the mountains of Canada and Alaska.
Now we come to the great and beautiful section of the antelopes, in which naturalists recognize thirty-five genera and perhaps a hundred species. Antelopes were scattered in Pleistocene days all over continental Europe and Asia, but never were present in America, for our so-called "antelope" is a pronghorn, as has been explained. Two or three species now inhabit the plains of central Asia—among them the swiftest mammal known, the Mongolian "orongo." The ungainly "nilgai" and the little "black buck" are familiar in India, and the pretty dorcas gazelle races across the sands of Syria and Arabia; but the vast majority of antelopes belong to Africa. They range in size from the duikerboks, not much bigger than fox terriers, to the eland, which has almost the bulk of an ox, and should be domesticated, like beef cattle, for its excellent flesh. No handsomer mammals than antelopes exist, judged by either form or coloring. They inhabit all sorts of country, too, as in other lands do the deer, of which Africa has none. Deserts, such as the Sahara and the Kalahari, and the stony steppes of Somaliland, support not only the swift and agile gazelles, but several large kinds. The grassy plains of South Africa were formerly, and to some extent still are, the pastures of great herds of such antelopes, large and small, as blesboks, wildebeests (or "gnus"), hartebeests, steinboks, springboks, and many others. Springboks used to assemble at certain seasons, and migrate across the veldt in countless thousands, allowing nothing to stop the headlong rush of the host. The thick jungle is the refuge of the harnessed antelopes, and of several diminutive kinds rarely seen in the open; and along the watercourses, and in marshes, live the big red waterbucks, the shy sitatungas, whose feet are curiously modified to fit them to walk on boggy ground; while rocky hills are the chosen home of the klipspringers and duikerboks, agile pygmies that creep about among the brush like big rabbits, or leap from rock to rock like miniature goats. A score or more of the species of these beautiful creatures have been carelessly or wantonly exterminated, and many others have become rare, but protective laws are now in force in all the parts of Africa controlled by the Government of South Africa, or organized as British, French, or Belgian dependencies.
The quaint and complex musk ox, a lone relic of a past era now exiled to the remotest north, is a connecting link between the sheep and the cattle, the last and best of the ruminants. Here, as elsewhere, the style of the horns is characteristic of the group—slender, backward curved or twisted, and somewhat compressed or keeled, in most antelopes; heavy, cross-ridged, triangular in section and often spiral in the sheep and goats; rough and helmetlike in the musk ox and some buffaloes; and in the oxen round, smooth and always springing from the side of the skull. The cattle fall into three groups: buffaloes, bisons, and oxen.
The buffaloes are tropical cattle, usually heavily built, with massive, flattened, wrinkled horns, and the hair so thin that in old animals the bluish black skin is left almost naked. The typical buffalo is that native to India and Ceylon, where it formerly roved in herds, which, quickly forming into a compact bunch, heads and horns out, defied attack from even the lion or tiger. Bulls often exceed five feet in height, are extremely strong and quick, and carry rough horns, sweeping back circularly, which may measure twelve feet around the curve. Such a veteran herdmaster spends his days wallowing in marshy jungles, his broad, splayed hoofs sustaining him in the muddy soil, and his hairless back, coated with clay, proof against insects; but evenings and mornings he leads his band out to feed in lush prairies where the grass is tall enough to hide them. This is the race that has supplied the working cattle of hot, swampy regions, especially where rice is grown, and that has been the farmer's servant in the Far East, in Egypt, and in parts of Spain and Italy from time immemorial. Several breeds have been developed, of which the best known to Americans is the carabao of the Philippines. Africa has native buffaloes in two species, neither of which has been domesticated. The African buffalo is regarded as perhaps the most dangerous brute a sportsman can meet in that land of irritable beasts. Only rarely will even the lion attack one single-handed, and then seldom succeeds.
The bisons, although regarded by systemists as of two species, the North American "buffalo" and the European "wissent," are as nearly alike as well can be. The latter originally ranged over all Europe, and was necessarily a forest animal, and hence never could assemble into herds as did its American cousins. It has been protected on the Czar's and other great estates in Lithuania and Russia, to the number of about 700; but these preserves were ravaged during and after the World War. The wanton waste that swept away the millions of our American bison in a few short years would long ago have exterminated this species also had it not been preserved in bands here and there in the West and in various animal collections. The peculiarity of the bison is the massive, humplike strength of the fore quarters, the great mop of hair upon them and about the head, and the short, stout horns growing straight out of the side of the head.
The animal called "bison" by sportsmen in India is the gaur, one of four species of true oxen inhabiting southeastern Asia—heavy animals with massive, upcurved horns, a long, ridgelike spine, short tail, and fine, glossy, dark-colored hair. A big bull of the gaur or "sladang," as Malays call it, will stand six feet tall at the shoulders, and is one of the greatest game animals of the world in every sense of the word. Celebes has a curious dwarf ox, the "anoa," which is hardly bigger than a goat. Contrasted with this is the great ungainly yak of Tibet and the high Himalayas, where it still wanders in a wild state, although large herds are kept by the Tibetans as beasts of burden in a region where hardly any other large grazer can exist. Finally, the Orient is the home of an extraordinary race of ancient domestic animals, the white, humped cattle of India, of which many breeds exist, modified by local conditions and purposes, and prehistorically used in Egypt and probably southward. No wild animals of its kind exist, and we know nothing of the origin of the race.
We now come to the most interesting species of the family, now extinct as a wild animal, but perfectly traceable—the primitive wild ox of Europe, the original of our farm cattle. It was much larger than any modern breed, and bore immense, wide-spreading horns, as still do certain coarse breeds in southern Europe, and especially in Spain, whence the herds of long-horned cattle of America were derived. Old bulls were black, but there is reason to suspect that the cows and calves may have been red. This great animal roamed throughout Europe and western Asia, and was counted among the fiercest of game in Cæsar's time, who found it called "ur," or "aurochs"; the former word was Latinized as urus, and the latter, when this ox had disappeared, became transferred to the bison. Even in Roman times the wild ox was growing scarce, and it died out early in the seventeenth century. Meanwhile, from prehistoric days, calves have been tamed by the peasantry, and such cattle as Europe and the Mediterranean basin generally possessed were until quite recently little better than rough descendants of this captured stock.
The so-called "wild white cattle" preserved in various British parks are, according to Lydekker, albino descendants of the tamed native black aurochs stock, of unknown antiquity, and are kept white (with blackish or reddish ears and muzzles) by weeding out the dark-colored calves which occasionally appear; but do not represent the original aurochs as well as do the Welsh breed preserved in Pembroke since prehistoric days. These park cattle are all of moderate size, elegantly shaped, with soft hair, white, black-tipped horns of moderate length, and many wild traits.
[CHAPTER XXXIII]
BEASTS OF PREY—THE CARNIVORA
"One of the most striking and significant results of the study of the later Mesozoic and earliest Tertiary mammalian faunas," remarks Prof. W. B. Scott, "is that the higher or placental mammals are seen to be converging back to a common ancestral group of clawed and carnivorous or omnivorous animals, now entirely extinct, to which the name of Creodonta was given by Cope. The creodonts are assuredly the ancestors of the modern flesh-eaters, and, very probably, of the great series of hoofed animals also, as well as of other orders. From this central, ancestral group the other orders proceed, diverging more and more with the progress of time, each larger branch dividing and subdividing into smaller and smaller branches, until the modern condition is attained."
The story of the creodonts—savage marauders large and small—includes the rise of the powerful order Carnivora—the beasts of prey, whose food is the flesh of other animals. There always has been, and always will be in every department and rank of animal life, some or many species that live by preying on their neighbors; and every living thing, from monad to man, has to fear such enemies.
The essential characteristic of the Carnivores is the dentition, which is adapted to seizing, holding, biting, and cutting. The canines, rarely prominent in other groups, here become of prime importance—a dagger and hook in one—a tearing instrument. Naturally this tooth is most developed in the dogs and the bears, which have little other means of seizing and holding an animal, whereas the cat has efficient aid in its claws. The cheek teeth in this order are (typically) not flat "grinders" but angular and knife-edged, especially the foremost molars that shut past one another like scissor blades; and it is evident that such teeth are necessary to animals that must cut their food into pieces small enough to swallow, and are not concerned about chewing it. The order contains two distinct divisions, namely:
Marine Carnivores—Seals, sea lions, walruses.
Land Carnivores—Cats, dogs, weasels, bears, etc.
The marine carnivores (suborder Pinnipedia, "fin-footed") have their whole organization adapted to an aquatic life, and appear to have acquired it almost from the beginning of the diverse specialization that sprang from the generalized creodonts, for nothing is known of their ancestry that connects them with the known lineage of their kin on land. The body approaches a fishlike form, and the four limbs are turned into more or less perfect paddles, or "flippers." The teeth are of the carnivorous type; the eyes are always large and prominent; and external ears are lacking except in one family.
The least modified of the three families of marine carnivora is that of the eared seals—the sea lions and fur seals of the North Pacific ocean, and southward to Cape Horn. They have kept much independence of action in the hind limbs, and are able to climb readily about the rocks of the islands and shores to which they resort in midsummer for the birth of the young. They have an obvious neck, small external ears, nostrils at the tip of the snout, and in general more characteristics like those of land carnivores, especially the bears, than have any other pinnipeds. They live wholly on fish. Several species termed "sea lions" were formerly numerous from Oregon southward to Patagonia, and on certain South Sea islands, but they have been all but exterminated except in California. These southern species, dwelling in warmer latitudes, are known as "hair" seals, because their coat lacks the warm undercoat of the northern species (Otaria ursina) which is the "fur" seal of commerce, and which would long ago have disappeared had it not been placed under international protection in its breeding places on islands in Bering Sea. Thither, as summer opens the ice, gather the herds that have been wandering in the ocean during the winter. The females are much the more numerous of the two sexes, and having spread all over the islands, formerly in hundreds of thousands, are collected into "harems." The "bulls" are three times the size of any of the females, and there are incessant combats between rival bulls. The young born here are strong enough to swim away with their mothers in the early autumn.
Similar in general organization, and in the freedom and usefulness of the hinder limbs for creeping on land or ice, are the walruses (Trichechidæ), of which there are two arctic species, one in the North Atlantic, and one in the seas of Alaska and Kamchatka. In old times they came as far south in winter as Nova Scotia and the coasts of Britain. A full-grown male walrus is a very bulky animal, ten to twelve feet long, and his skin is covered with a short coat of hair that in old age almost disappears, while his bulldoglike muzzle bristles with quill-like whiskers. The especial feature of the walrus, however, is the pair of great ivory tusks, often two feet or more long, which are the canines of the upper jaw. They are the tools with which the animal digs from the mud of the bottom the clams and other shellfish on which it feeds, and are formidable weapons enabling it to protect itself and its family and mates, for which the walrus shows remarkable affection and loyalty, from the attacks of the polar bear, the only enemy besides man that it has to fear.
The true seals (Phocidæ) have become still further specialized toward a completely aquatic life. Their hind limbs are extended straight behind the body, and take no part in progression, the fore flippers alone enabling them to swim and dive with ease and speed. Their strong, clawlike nails enable them to climb onto ice floes or the shore, to which they resort for rest and sunshine and to bear their young. These are usually only one, or at most two, at a birth, and in some species they have to be carefully taught how to swim, fearing the water. All of the many kinds of seals of this family are confined to the northern hemisphere, and mostly to the arctic region; but the great sea elephant, now almost extinct, lived in the antarctic, with one colony on the coast of southern California. Most seals are gregarious, and some congregate in immense herds on ice floes far from land, but the majority of species stay near shore. Seals feed chiefly on fish, of which they consume enormous quantities; some, however, subsist largely on crustaceans, especially prawns that swarm in the northern seas; also on mollusks, echinoderms, and even occasionally on sea birds.
We are now ready to turn to the land carnivores, which, by the larger opportunity, better food, and varied conditions the land affords, have advanced far beyond their marine cousins. In these more favorable circumstances, and by their struggle for a living against the powers of defense or escape of their intended prey, and the competition of one another, they have become widely diversified in organization and habits, and in some of their representatives have developed the highest intellectual and physical ability in the animal kingdom.