Fig. 219.
Fig.219.—Tayra.Galictis barbara.×1⁄7.
Galictis barbara,[292]the Tayra, is a brown, elongated, and Weasel-like animal from Mexico and South America. As is the case with the Weasel, it is sometimes gregarious, a herd of twenty having been observed. The soles of the feet are naked, and the molar formula is Pm 3/3 M 1/2. In these characters the Grison (G. vittata) agrees withG. barbara; but it has been referred to a different genus,Grisonia.
The Grison, "this savage and diabolical-looking weasel," asMr. Aplin terms it,[293]is known also as the "Hurón." It almost rivals the Skunk in the power of the odour which it can emit when enraged. A trapped specimen was placed in a cage 50 yards or so from the house, and even at this distance it was disagreeably easy to tell when any one visited the animal—at least when the wind set in the right direction. It is greyish yellow above and blackish beneath, presenting, as has been remarked, a curious similarity to the Ratel. The nose of this animal is destitute of a median groove, which is present in the Tayra; the soles of the feet, however, are naked as in that animal, and it is nearly plantigrade in walk. It differs also fromGalictisin having sixteen[294]instead of fourteen dorsal vertebrae. Eleven of the ribs reach the sternum. Considering the differences that exist between some other genera of Arctoids, it may be fairly allowed that a genusGrisoniais tenable.
Fig. 220.
Fig.220.—Grison.Grisonia vittata.×1⁄7.
G. allamandiis darker coloured than the Grison, with a white band from the forehead to the neck. Mr. T. Bell described a tame individual as eating eggs, frogs, and even a young alligator.
A third genus of this group has recently been founded by Mr. Oldfield Thomas[295]for a small African animal, which is Grison-like in its coloration. The name given to the genus,Galeriscus, is intended to suggest its likeness to the Grison (GaleraorGrisonia). The chief distinctive feature of this genus, whose skeleton is not yet known, is the presence of only four digits on each limb; the pollex and the hallux being entirely absent. The ears of this Grison are short.
The genusMustelaincludes the Martens and Sables, which are distinguished from the following genus by the molar formula, which is Pm 4/4 M 1/2. The same character separates them fromGalictis, and also the generally hairy under surface of the feet. In more southern latitudes, however, the palms are sometimes naked. The nose is grooved, and the ears are short and broad. The genus is widely distributed, being common to the Old and New Worlds. In the Old World it extends from Europe to Java, Sumatra, and Borneo. The largest species of the genus is the American Pekan, an animal which may be 46 inches in length, including the tail. There are two species of Sable, one European (M. zibellina), the other American.
The only British species of the genus is the Pine Marten,M. martes. It is dark brown, with a brownish-yellow throat, and reaches a length of some 17 inches, with an eight-inch tail. It is getting rare, but is still fairly common in the Lake country. The animal is largely arboreal in habit, whence the vernacular name. It is also called Marten Cat. The alliedM. foina, the Beech Marten, has been stated to be, but apparently is not, an inhabitant of these islands. The colour of the animal is a rich brown. It has small eyes and ears and a short tail. The palms of the hands and the soles of the feet are hairy; the muzzle is naked, and has a groove as inCercoleptes, etc.
The Glutton,Gulo, is a well-marked genus, containing but one species, which is circumpolar in range. The dentition is Pm 4/4 M 1/2. The ferocity but not the voracity of this animal appears to have been exaggerated. It mainly feeds on carcases, and is not really a successful hunter. As to the carcases, Olaus Magnus tells in straightforward language the way in which the animal dilates in size during a meal, and presently, after following the practice of the ancient Romans, returns to the banquet: "Creditur a natura creatum ad ruborem hominum qui vorando bibendoque vomunt redeuntque ad mensam"!
This is one of the few land animals which ranges completely round the pole. There is no difference to be noted between the Old-World and the New-World specimens. It is now an entirely northern form, but in Pleistocene times it reached as far south as this country. The fossil species seems to beGulo luscus, and to be quite indistinguishable from the living forms.
Putorius, the genus which embraces the Weasel tribe, containsmany species known popularly as Weasels, Ermines, Stoats, Ferrets, Polecats, Minks, and Vison. Not only is the genus common to both Old and New Worlds, but in a few cases the species (e.g.P. erminea) range from Asia to America. The molar formula is Pm 3/3 M 1/2. The form of the body is an exaggerated one, the length of the trunk to the limbs being very great. The feet are more or less hairy beneath, and the animals are digitigrade. The nose is grooved. The dorsal vertebrae vary from thirteen to sixteen.
Fig. 221.
Fig.221.—Polecat.Mustela putorius.×1⁄6.
There are four British representatives of this genus:—
The Polecat,P. foetidus, is a dark brown-coloured animal. Its total length is about 2 feet, of which the tail occupies some 7 inches. It is a species banned by the gamekeeper, and hence is approaching extinction in this country. It is excessively bloodthirsty, as are apparently all the members of this genus, and kills out of mere wantonness. The Ferret is simply a domesticated variety of the Polecat.
The Stoat or Ermine,P. erminea, is reddish brown above, white beneath. In winter, in certain localities, it becomes white with the exception of the black tip of the tail. This colour-change bears some relation to the degree of latitude. It is universal in the north of Scotland, rare in the south of England. As is the case with some other animals that generally changetheir colour in the winter, there are individuals which seem to have lost the power of change, and others which change in an apparently capricious manner, not influenced by season or cold. Like so many other animals, the Stoat appears at times to migrate, which it does in large parties. Such parties are said to be dangerous, and will attack a man who crosses their path.
The Weasel,P. vulgaris, has much the same colour as the Stoat, but is a smaller animal; it differs also by undergoing no seasonal change. It is equally agile and ferocious, and ought to be encouraged, as it vents its ferocity largely upon Voles and Moles, which it can pursue underground. Like other species ofPutorius, it seems to kill its prey by biting through the brain-case.
The fourth British species is the recently-described Irish Stoat,P. hibernicus. It is somewhat intermediate between the last two.
Poecilogaleis a genus recently instituted by Mr. Thomas for a small South African Weasel,P. albinucha, coloured like the Zorilla,i.e.with whitish stripes upon black, but differing in its reduced molar formula, which is Pm 2/2 M 1/1 or 1/2.
Lyncodon[296]is thought to be more doubtful; it is South American (Patagonian), with the same molar formula as the most reduced forms of the last genus,i.e.Pm 2/2 M 1/1. The ears are short and almost invisible; the claws of the anterior limbs are long, those of the hind limbs short. It is not quite certain that it is not "an aberrant southern form ofPutorius brasiliensis." That its distinction is justifiable appears to be shown by the discovery in the same region of a fossil species,L. luganensis. Matschie places it nearGalictis.
The Ratel,Mellivora, is common to India and West and South Africa. It is a black animal with a grey back and grey on the top of the head, the contrast of colour suggesting a dorsal carapace. It runs with a swift trot. The animal lives much on the ground, but can climb trees. It is exclusively nocturnal in its habits. It has the reputation in India of feeding upon dead bodies, a view which has probably no foundation in fact save that it can burrow. The molar formula is Pm 3/3 M 1/1. There are fourteen dorsal vertebrae. The African and Indian species arehardly to be distinguished from each other. The ears are very minute. The tail is short. The muzzle is rather pointed, and the soles and palms are naked.
Fig. 222.
Fig.222.—Ratel.Mellivora capensis.× ⅛.
The structure ofHelictishas been described by the late Professor Garrod,[297]as well as by Sir W. Flower in his general account of the Carnivorous skeleton. The animal, which is a native of East Asia, is sometimes gaily coloured.H. subaurantiaca, the species dissected and figured by Garrod, is a varied black and orange. The genus is arboreal, and the tail may be moderately long and bushy. The ears are small; the nose is grooved; the palms are naked, but the soles of the feet are hairy. There are fourteen dorsal vertebrae. The molar formula is Pm 4/4 M 1/2.
The Zorilla,Ictonyx, is the last of the Old-World genera of Melinae. It is African, ranging from the tropical parts of the continent to the Cape. "In colour and markings," remarks Dr. Mivart, "as well as in the odour of the secretion of its anal glands, the one or two species which form this genus resemble the skunks; so much so that did they inhabit the same region, and were they devoid of an offensive secretion, they would certainly be said to mimic the skunks." The molar formula of the genus is Pm 3/3 M 1/2. There are fifteen dorsal vertebrae. The nose is grooved and the soles partly hairy.
The American Badger,Taxidea, is a burrower of omnivorous tastes, and correlated with the former habit are the immenseclaws of the fore-paws. It is North American, but gets into Mexico. The molar formula is as in the American generaMephitisandConepatus, and as in the Old-WorldIctonyx, and it thus differs from that ofMeles. Besides the great size of the claws upon the hand, which are larger relatively than those of any other Carnivore, the genusTaxideais to be distinguished from all Arctoids (indeed, from all Carnivora) exceptMydaus, by the fact that the pelvic limb is of the same length as the pectoral. The muzzle is furry except at the very extremity; this is grooved. The animal is carnivorous, subsisting upon the following very varied kinds of food—"Spermophiles, Arvicolas, birds' eggs, and snails, also honey-comb, wax, and bees."
The Skunk,Mephitis, is an American animal with several species, which range from North to Central America. The black-and-white colour distinguishes the genus, which is furthermore marked by the fact that the third digit of the hand is relatively longer than in any other Carnivore exceptTaxidea. The soles are partly hairy. It is a terrestrial fossorial animal with well-known powers of protecting itself from aggression. But nevertheless the Skunk has its enemies, and is not quite so unmolested as is sometimes popularly supposed. The Puma, Harpy Eagle, and the Great Horned Owl will at least occasionally attack and devour it. The molar formula is Pm 3/3 M 1/2. There are sixteen dorsal vertebrae.
Conepatusis a more southern form of Skunk, extending down into South America. Its dentition is like that ofMephitissave for the loss of an upper premolar. This genus, which has been further subdivided, differs fromMephitisin the fact that the soles of the feet are wholly naked, whereas in Mephitis those of the hind-limbs are partially hairy. It has no groove on the nose. Its tail is shorter than that ofMephitis. This Skunk has the same habits as the last. In certain parts of South America the animals are so abundant and their odour so powerful that in the evening there is generally a recognisable smell about. This is said to be good for the headache!
Sub-Fam. 3. Lutrinae.—Of this sub-family there are at least two genera.Enhydris(Latax),[298]the Sea-Otter, is confined to the shores of the North Pacific. It is more purely aquatic than areother Otters. Specimens have been seen swimming fifteen miles from land. The gait of the creature when on land is suggestive of a marine animal; the webbed hind-feet are doubled back upon the knuckles during progression upon land, and locomotion is effected by a series of short springs from these feet; the Otter does not walk "in ordinary acceptance of the term." The tail is flattened, being twice as broad as it is thick, and ends in a bluntish point.Enhydrisfeeds mainly upon crabs and sea-urchins, but also upon fish. Its dental formula is peculiar by reason chiefly of the reduction of the lower incisors. The formula runs as follows: I 3/2 C 1/1 Pm 3/3 M 1/2.
The molar teeth of this creature, in accordance with its diet, have lost the sharp points of the Mustelidae in general; the crowns are flattened, and the tubercles very blunt. In this it contrasts withLutra, and presents some resemblance to the Crab-eating Raccoon,Procyon cancrivorus; but the teeth are still further blunted.Enhydrisfeeds largely upon sea-urchins and shell-fish, and needs blunt teeth for the crushing of the hard shells of its prey. It is interesting to notice that the habits of this animal have been altered by the interference of man. The creature has been hotly pursued for a long time on account of its valuable fur. Instead of feeding and breeding upon the shore in places readily accessible to its pursuers, the Sea-Otter has now taken to the open sea in a greater degree. It utilises masses of floating seaweed for those purposes, and hunts for its food in the deeper water at a greater distance from the shore. In conjunction with the increasing rarity of the Sea-Otter the price of its skin has enormously increased: whereas in 1888 the average price per skin was £21:10s., the value of a fine skin now is at least £100, and as much as £200 and even £250 has been given. The animal is captured by netting and by clubbing and spearing.[299]From the Miocene Siwalik beds remains of an allied form,Enhydridon, have been obtained, whose teeth are somewhat intermediate in their crowns betweenLutraandEnhydris.
Lutra, including the Otters, is widely distributed. Both manus and pes are webbed. The ears are small and hairy. The nose is not grooved, and the naked part is very circumscribed;the claws upon the hind-feet are flattened and somewhat nail-like. There are about ten species, but of course, as is so universally the case, a great many more names have been given. The molar formula is like that ofEnhydrissave that there is an extra premolar in the upper jaw. There are fourteen pairs of ribs, of which eleven pairs reach the ten-jointed sternum. The caudals are twenty-three. The Cape Otter, the "clawless" Otter, has been separated as a genusAonyx. So too has the South AmericanPteronura brasiliensis. But in neither case is the separation allowed by Mr. Thomas in a recent revision of the genus.[300]The latter species has the reputation of being very fierce, and is known in Uruguay by the name of "Lobo de pecho blanco." The British species,L. vulgaris, reaches a length of 2 feet or so, with a tail of 16 inches; it ranges over the whole of Europe and a large portion of Asia. This Otter often burrows in the banks of the streams which it frequents; and in the burrow in March or April the female brings forth her young, three to five in number. It will also frequent the sea-coast.
Fig. 223.
Fig.223.—Otter.Lutra vulgaris.×1⁄6.
Fossil Mustelidae.—Besides a number of the existing genera there are fossil members of this family which cannot be referred to existing genera. These latter extend back into time as far as the Eocene.Stenoplesictis, one of these Eocene forms referable to the sub-family Mustelinae, is to be distinguishedfrom living Mustelines by its comparatively long legs. In this genus as in several others there are two upper molars.
Fam. 8. Ursidae.—This family is nearly universal in distribution, and consists of but three genera,Ursus,Melursus, andAeluropus.
Ursushas the palms and soles naked except in the Polar Bear, which needs a furry sole to walk with ease upon ice surfaces. The ears are fairly large, and the nose may or may not be traversed by a median groove.[301]The molar formula[302]is Pm 4/4 M 2/3. The brain is naturally (because of the size of the animals of this genus) richly convoluted. The lobate kidneys have already been mentioned in defining this family (see p.426).
Fig. 224.
Fig.224.—Himalayan Bear.Ursus tibetanus.×1⁄15.
A very large number of species of Bears have been described. But it is the opinion of Mr. Lydekker[303]and of others that many of these are really to be referred to the European Brown Bear; in this event the Grizzly of North America, the Isabelline Bear, the Syrian Bear, a Bear from Algeria, the Kamschatkan and Japanese Bears, besides the extinctUrsus fossilisof Pleistocene caves, are to be regarded as slight modifications ofUrsus arctos. On the other hand, the great Cave Bear,U. spelaeus,and the Thibetan Blue Bear (U. pruinosus) are distinct species, not to be confounded withU. arctos. Neither, of course, are the PeruvianU. ornatusand the Sun Bear,U. malayanus.
Fig. 225.
Fig.225.—Malayan Bear.Ursus malayanus.×1⁄12.
The Polar Bear has even been placed in a separate genus,Thalassarctos, a proceeding which is quite unnecessary. The white colour of this Bear tends to become browner with age. It is one of the few mammals which extend right round the pole; the Polar Bear is of course a purely Arctic animal. The chief food of the Polar Bear is Seal. Out of thirty Bears examined, Mr. Koettlitz found that only fifteen had animal remains in their stomachs, and these remains were invariably Seal. The animal apparently hunts by scent rather than by sight or hearing, both of which senses seem to be somewhat dull. The males and females wander separately, except of course during the breeding season. The Bears dig holes in which they may remain for some time, but there is no hibernation. In Pleistocene times, the Polar Bear extended as far south as Hamburg. The female has four mammae, pectoral in position.
Melursusincludes onlyM. labiatus, the Sloth Bear of India. This animal has an upturned snout, which is described as closely resembling that ofMydaus, the Teledu. The snout has no groove.All Bears are largely vegetarian and insect feeders; but this Bear is especially so. It delights in the nests of Termites, and its energy in destroying these hills for the sake of their inhabitants is so great that the name of "sloth" appeared to Sir Samuel Baker to be an entire misnomer.
Aeluropus, a rare Carnivore with but one species,A. melanoleucus, is not inferior in size to the Brown Bear, and is distinguished by its largely white coloration. It was discovered in the mountains of East Thibet by Père David, and described by Milne-Edwards[304]as a distinct and new genus, the discoverer himself having named it as a species ofUrsus. It is a vegetable-feeding creature and bulky in form, with a rudimentary tail and a short broad head; in fact, more like a Bear than a Procyonid (with which group it is placed by some). The width of the head, however, is greater than in any other Carnivore; it is most closely approached in this byAelurusand byHyaena. The molar formula is Pm 4/3 M 2/3. The soles are hairy. There is no alisphenoid canal. The molars are especially large and multicuspid.
Fig. 226.
Fig.226.—Aeluropus melanoleucus.×1⁄12.
Fossil Ursidae.—The genusUrsusitself goes back to Pliocene times. The well-known Cave Bear,Ursus spelaeusofPleistocene times, was one of the commonest of Carnivorous creatures during the very early times of the present era. It was as huge as a Polar Bear or a Grizzly. The skull is remarkable for the fact that the first three premolars, which are small in all Bears, dropped out early in life. An immense number of names have been given to what are in all probability the same species as this Cave Bear of remote antiquity.
Hyaenarctosis the oldest genus of true Ursidae. It goes back into Middle Miocene times, and ranged over Europe and North Africa.
Arctotheriumis an American genus of Pleistocene times. The likeness of some of the extinct Canidae to Bears has been already commented upon.
This group includes the Seals, Sea-Lions, and Walruses,[305]all aquatic and, for the larger part, marine creatures. Being aquatic they have to some extent acquired a fish-like form, though not so completely as have the Whales and even the Sirenia. This is most complete so far as the group is concerned in the Seals, where the hind-limbs have become soldered to the tail and are inefficient as walking legs, where the external ears have vanished, and where the general shape of the body is tapering and thus fish-like. The Walruses and Sea-Lions are less modified in this direction; in the latter (not in the former) the external ear, though small, is persistent, and the hind-limbs are capable of being used as organs of progression upon dry land. The general characters applicable to the Carnivora, given upon a previous page, apply to the Pinnipedia.
Fig. 227.
Fig.227.—Skeleton of Seal.Phoca vitulina.(After de Blainville.)
The characters confined to the Pinnipedia as a whole are mainly these:—The greater part of the limbs are enclosed within the skin, the hands and feet are fully webbed, and there is a tendency for the nails to disappear, and for the phalanges to increase in number—characters which are clearly not diagnostic of the order but correlated with an aquatic life, since they reappear, and are indeed exaggerated, in the Cetacea. The teeth are peculiar in that the milk dentition is feeble and is early shed. This, as it were, undue emphasis upon one of the two sets of teeth is another likeness to the Whales,where, however, it is the milk dentition that is most pronounced, the "permanent" being feeble and very early shed. But the dentition of the Pinnipedes presents other likenesses to the Cetacea, which are, it must be remembered, regarded by some as a modification of the Carnivorous stock, in which case, of course, the likenesses may be genetic rather than due to adaptation in the two cases. There is a distinct tendency towards a homodont series, the grinding teeth being often very simple, and the very distinct carnassial tooth of many terrestrial Carnivores being absent. Finally, the number of the back teeth shows some signs of being on the increase; and Professor Kükenthal has found that this increase is due to the division of existing teeth. Here is a point of likeness to the many teeth of the typical Toothed Whales. Dr. Nehring found in several examples ofHalichoerus grypusthe normal five back teeth increased tosix, and the additional molar was at the end of the series, thus suggesting a lengthening of jaw coupled with an increase in number of teeth.
The incisor teeth of the Pinnipedia differ from those of the land Carnivora in that there are nearly always fewer than 3/3, at least in the adult animal. In possessing lobulated kidneys the Pinnipedia differ from all terrestrial Carnivores except the Otters and Bears—a significant fact.
In the characters of the skeleton the Pinnipedia show many peculiarities. The cranial part of the skull is proportionately to the facial part greater than in terrestrial Carnivora; there is no lachrymal bone, and the orbit is to some extent defective in ossification. The alisphenoid canal, so important a feature in the Carnivora, may be present or absent. It is present, for example, inOtaria jubata.[306]This genus also has the more primitive small and rugged tympanic bullae, which are inflated and more Cat-like in others. The vertebrae show an interesting Creodont peculiarity in the complex interlocking arrangements of the zygapophyses of the dorsal vertebrae. The ossicula auditus differ from those of their terrestrial allies in their large size and massive growth. In this they have come to be like those of the Whales and Sirenians.
Fig. 228.
Fig.228.—Patagonian Sea-Lion.Otaria jubata.×1⁄20.
There is no doubt about their close resemblance to theterrestrial Carnivora, but the question is, to which group of Carnivora have they the most likeness. The semiaquatic Otter, and the still more thoroughly aquatic (marine)Enhydris, suggest an affinity in that direction. The long body and short legs of the Otter, which is more thoroughly at home pursuing fish in the streams than in waddling clumsily upon the banks of the streams, seem to require but little external change to convert it into a small Seal, while the long and completely webbed hind digits ofEnhydrisare even more like those of a Pinniped. The Sea-Lions, in which the external ear has been preserved, and in which the limbs have not become so entirely useless for progression on the land as they have in the Seals, seem to be the intermediate step in the evolution of the latter. This, however, is not the opinion of Dr. Mivart, who, without definitely committing himself on the point, presents some evidence for the assumption that the marine Carnivora are diphyletic. This double origin, however, is not from two groups of the terrestrial Carnivora. Dr. Mivart, in common with many others, holds that the Pinnipedia as a whole are undoubtedly nearer to the Arctoidea than to either of the two remaining sections of the sub-order. One of the most striking structural characters in which they show this resemblance is the brain; the peculiar Ursine lozenge, already treated of as so distinctive a character of the Arctoidea, is repeated in the Pinnipedia.
There are, however, other points of likeness which seem rather to point to a Creodont origin.Patriofelisis a genus that from more than one side may be looked upon as a possible ancestor of these animals. The Creodont peculiarity of the vertebrae has already been referred to. It may be added that the facial part of the skull is small inPatriofelis, which appears, moreover, to have had an alisphenoid canal. A very remarkable resemblance lies in the structure of the astragalus. This is not deeply grooved on the tibial facet as it is in Fissiped Carnivora. This might be held to be an instance of degeneration in the aquatic Seals, which do not use their limbs as walking organs. But Professor Wortman[307]has pointed out that in the Sea-Otter, which is entirely aquatic, the groove exists and is plain. The likeness offered to the Seals by the spreading feet ofPatriofelisis noticed under the description of that genus.[308]
Fig. 229.
Fig.229.—Cape Sea-Lion.Otaria pusilla.×1⁄16.
Fam. 1. Otariidae.—The family Otariidae[309]is no doubt the least modified of the aquatic Carnivora. It is rational, therefore, to commence the survey of the group with this family. They have preserved, as already noted, the independence of the hind-limbs; the external ear is present, though small; there is an obvious neck, and the nostrils are at the end of the snout, as in terrestrial creatures generally. The nails are small and rudimentary, save those upon the three middle digits of the foot. It is a singular fact that among the Otaries the angle of the lower jaw is "inflected as much as in any Marsupial." The literature relating to this family is great, and it seems difficult to reconcile the very varying opinions as to how many genera ought to be admitted. Mr. Allen arranged the nine species which he allowedin six genera; but more generic names have been proposed. At the other extreme stands Dr. Mivart, who speaks of only one genus,Otaria; of this genus the number of species is by no means agreed upon. There can, however, be no doubt of the distinctness of the Northern Fur Seal,O. ursina(the "Seal" of commerce and the cause of international complications), of the Patagonian Maned Sea-Lion,O. jubata,[310]ofO. pusillaof the Cape, of the CalifornianO. gillespiei, ofO. hookerifrom the Auckland Islands, and of four or five others. The range of the genus is wide, but is mainly Antarctic. It is usual to speak of "Hair Seals" and "Fur Seals," the latter being the species which produce the "sealskin" of commerce. The difference is that in the Fur Seals there is a dense, soft under-fur, which is wanting in the other group. It is, however, impossible to make this character the basis of a generic subdivision. There is a Fur Seal,O. nigrescens, in South America as well as the more widely-known northern form.
Fam. 2. Trichechidae.—This family contains but one genus,Trichechus, the Walrus or Morse, orOdobaenus, as the more correct term seems to be. It is a tiresome result of accurate conformity with the rules of priority in nomenclature that the nameTrichechusshould be applied to the Manatee. There is but one species of Walrus, though it has been attempted to show that the Pacific and Eastern forms are different. The animal is Arctic and circumpolar. The Walrus is characterised by the enormous canines of its upper jaw, which form the well-known tusks and reach a length of 30 inches. The animal can progress on land like the Sea-Lions; but, as in the Seals, there are no external ears, though there is a slight protuberance above the meatus auditorius. The strong bristles upon the upper lip are as thick as crow quills. The pectoral limb has nails, but these are small, as in the Sea-Lions. The under surface of the manus has a warty pad, which cannot but assist[311]in maintaining a foothold upon slippery ice. The hind-limbs have longer nails, which are still diminutive and subequal in size. There is no free tail. The liver of this animal is much furrowed, but not so much so as inOtaria, though more so than inPhoca. The kidneys are of course lobulate, as in the other aquatic Carnivores. The milk dental formula appears to be I 3/3 C 1/1 Pm + M 5/4. In the adult the formula[312]is I 1/0 C 1/1 M 3/3.
Fig. 230.
Fig.230.—Common Seal.Phoca vitulina.× ⅛. (From Parker and Haswell'sZoology.)
Fam. 3. Phocidae.—The true Seals have no external ears, and the nostrils are quite dorsal in position as in other aquatic animals, such as the Crocodile. There is obviously an approach to the conditions characteristic of the Whales. The hind-limbs are useless for locomotion on land. They are bound up with the tail, and form functionally merely a part of the tail. In this family there are, at any rate, eight genera.
PhocaandHalichoerusare not very wide apart from each other. In both there are five well-developed claws on feet and hands. They are British, and generally Arctic and temperate in range. For some reason or other the late Dr. Gray placedHalichoerusin the same sub-family with the Walrus!Phocais not only marine, but is found in the Caspian and in Lake Baikal. Their existence in those inland seas is believed to be a vestige of a former connexion with the sea.Halichoerus grypusis a large seal 8 feet in length when full grown. Its colour is yellowish grey, with darker grey spots and blotches. It is not uncommon on the shores of our islands, particularly of the Hebrides and Argyllshire. The commonest Seal isPhoca vitulina, not more than 4 to 5 feet long, and of the same spotted coloration as the last. This Seal has, however, a much wider distribution, being Arctic as well as British, American, and North Pacific. A curious fact about this Seal is that it is not impatient of fresh water; not only will it ascend rivers, but it will live in inland lakes. It is said to be especially sensitive to musical sounds.P. hispidais British, but a rare visitor to our islands. It is essentially an Arctic species. The Harp Seal,P. groenlandica, is so called on account of a harp-shaped black bar in the males, which starts atthe shoulders and extends to the thighs. Like the other Seals mentioned, the young are white when first born. As may be inferred from its scientific name this species is also Arctic in range. It is also a rare visitor to these shores.
The genusCystophorais the only other genus of which there is a British representative. It is called the Hooded Seal on account of an inflatable sac upon the face, with which it is said to attempt to terrify its enemies. The genus has an incisor less in each half of each jaw thanPhocaandHalichoerus. Its formula is I 2/1 while these genera are both 3/2.C. cristatais a large species reaching a length of 10 feet. The colour of the back is dark grey with deeper coloured spots. A few individuals only have been recorded from our coasts.
Stenorhynchus( =Ogmorhinus) is an Antarctic genus. The hind-feet are clawless. The incisors are 2/2. The molars have an additional cusp,i.e.three in all.
The genusLeptonyxwith but one species,L. weddelli, is purely Antarctic in range. Like the last genus it has two incisors, and has but rudimentary claws upon the hind-feet; the first and fifth toes moreover are the longest. The genus chiefly differs from the last in the simple conical crowns of the molars, which have not the additional cusps ofStenorhynchus.
Ommatophocais another Antarctic genus with but a single species,O. rossi. In this genus the hind-feet have no claws, and the first and fifth toes are longer than the others. The claws of the fore-feet are rudimentary. The immense size of the orbits gives the name to the genus. There are two incisors, and the molars are all very small.
Monachusis a northern genus inhabiting the Mediterranean and the Atlantic in the vicinity of Madeira and the Canary Islands. It has rudimentary nails upon both pairs of feet. The first and fifth toe of the hind-feet are longer than the others. As with the preceding genera, the incisors are two in each jaw. The species areM. albiventer, the Monk-Seal, andM. tropicalis, the Jamaica Seal.
Allied toCystophorais the genusMacrorhinus, with (possibly) two species, of which one is Antarctic, the other frequents or frequented the coast of California. The incisors are two in the upper jaw, and but one in the lower. The premolars are four and the molar one; all the teeth are small and simple, buthave long roots. The nose of the male has a dilatable proboscis. The southern Elephant Seal isM. leoninus, and reaches a length of some 20 feet. It occurs on the shores of Kerguelen and some other more or less remote islands. Its habits have been studied and described by several observers, beginning with Anson in the last century. The late Professor Moseley gave a good account of this marine monster in his book on the voyage of the "Challenger." When the animal is enraged, the end of the snout is dilated; but when this happens there is no long and hanging proboscis such as has sometimes been described. The inflation affects the skin on the top of the snout, which thus rises rather upwards during inflation. The inflated region, according to Mr. Vallentin, quoted by Mr. J. T. Cunningham, is about 1 foot long in an individual of 17 feet. It has been stated that this proboscis is a temporary structure, only appearing in the breeding season; but recent observations have shown that this statement is inaccurate; it persists all the year round. The males fight greatly during the breeding season, and produce a roar which has been compared to the "noise made by a man when gargling." The females and the young males bellow like a bull. The males fight of course with their teeth, literally falling upon one another with their whole weight. Mr. Cunningham thinks that the use of the proboscis is to protect the nose from injury; or that it may be merely the result of "emotional excitement." In any case the Bladder-nosed Seal,Cystophora, is undoubtedly protected from injury by the possession of a corresponding hood. The nose is the most vulnerable place, and the existence of this hood would stave off the effects of a blow in that region. Moseley, however, has said ofMacrorhinusthat it cannot be stunned by blows on the nose as other Seals can; but he attributes this, not to the dilated snout, but to the bony crest on the skull, and to the strength of the bones about the nose. This Seal crawls with difficulty on the land, and as the animals move "the vast body trembles like a great bag of jelly, owing to the mass of blubber by which the whole animal is invested, and which is as thick as it is in a whale."[313]When lying on the shore, these animals scrape sand and throw it over themselves, apparently to prevent themselves from beingincommoded by the direct rays of the sun, to the effects of which they are very susceptible. The Elephant Seal is mild and inoffensive, unless enraged, and, of course, during the breeding season.
This entirely extinct group of Mammalia may be thus characterised:—Small to large carnivorous mammals, with skull on the whole like that of the Carnivora and with trenchant teeth; digits with unguiculate phalanges; tail long; extremities usually with five, sometimes with four digits. In the carpus a centrale is present, and the scaphoid and lunar are separate. Interlocking of posterior dorsal and lumbar zygapophyses very perfect. Brain small but convoluted.
This group, which corresponds with theCarnivora Primigeniaof Mr. Lydekker, is not easy to separate absolutely from the existing and more especially from some of the extinct members of theCarnivora Vera. They also come exceedingly near the Condylarthra, the presumed ancestors of the Ungulata, and like them begin in the earliest Tertiary deposits. Their likeness to the carnivorous Marsupials has also been insisted upon; but it would seem that the succession of teeth in the Creodonta is typically Eutherian.
The characteristics of the group may be exemplified by an account of the genusHyaenodon, after which some of the more important deviations in structure shown by other genera will be referred to.
Hyaenodonis both American and European, and ranges through the Eocene and the Upper Miocene. It is a much-specialised Creodont, and therefore exhibits well the distinctive characters of the group. About a dozen species have been described. One of the best-known is the AmericanH. cruentus, and the following description refers to it. The back part of the skull is low and broad, and is compared by Professor Scott (who has described this and other species) as being "somewhat like that of an opossum."[314]The whole skull islong, and the top has a great sagittal crest. The paroccipital processes are short and are closely applied to the mastoid processes. The mesethmoid is larger than in the carnivorous Marsupials, and the frontals are very large. The palate has a peculiar structure; in most species the hinder ends of the palatines are separated by a narrow fissure which broadens gradually, thus forming the posterior nares. InH. leptocephalusthe posterior nares are brought very far back by the meeting of the alisphenoids. The presphenoid, contrary to what we find in the Dog, for example, is chiefly concealed by the vomer, which covers it. The mandible has a long and strong symphysis, and its angle is not inflected. The fore-limb is described as being "weak when compared with the modern Carnivora." The scaphoid and lunar are separate, and there is a centrale. The teeth present us with nearly the typical formula. There is only one molar missing in the upper jaw. The canines are enlarged. It has been suggested from a consideration of its palate thatHyaenodonwas a semiaquatic animal; the deep cleaving at the extremities of the phalanges seems to point in the same direction, since they resemble in this the genusPatriofelis, which there are other reasons to regard as aquatic. This latter genus has a fore-limb which is very like that of the Pinnipedia, the digits are much spread out, and would seem to have supported a kind of paddle. In any case it certainly fed upon aquatic tortoises, for their remains have been found in its coprolites. The nameLimnofelis, also applied to what appear to have been members of this genus, is suggestive of their habits.Patriofelis, at least one species, seems to have been of about the size of a Lion.
Mesonyxhas a brain case which is actually smaller than that of the MarsupialThylacinus. The lachrymal bone is very large, and extends a little way over the face, as is also the case withHyaenodon; this condition is also found in Insectivora and inThylacinus. The axis vertebra has a curiously-shaped spine, which is very different from the hatchet-shaped process of that vertebra usual in the Carnivora, but is not unlike what exists in the Arctoid generaMelesandMydaus. The limbs show much disparity in length, and seem to argue a much-arched back when the creature progressed. The carpus is stated to be strikingly like that of the Insectivora. There is as in other Creodonts a separation between the scaphoid and lunar;the centrale appears to be present. The pelvis "is most like that of the bear," the metacarpals and the tibia, and some other bones, resemble those of the Hyaena. In fact this animal shows those combined characters which are common in archaic forms.
Small to moderately large animals, furry, sometimes with spines. Toes with nails of a claw-like character, or sometimes approaching hoofs. Usually plantigrade, and only occasionally and partly carnivorous. Canine teeth absent; incisors long and strong, growing from persistent pulps, and with enamel only or chiefly on the anterior face, producing a chisel-shaped edge; molars few (two to six), separated from the incisors by a wide diastema. Caecum (nearly always present) very large, and often complicated in structure. Brain, if not smooth, with few furrows, the hemispheres not overlapping the cerebellum. Surface of skull rather flat; orbits not separated from temporal fossae; malar bone in middle of zygomatic arch; palate very narrow, with elongated incisive foramina; articular surface for lower jaw antero-posteriorly elongated. Clavicles generally present. Testes generally abdominal. Placenta deciduate, and discoidal in form.
The Rodents are a very large assemblage of usually small, sometimes quite minute, creatures, embracing an enormous number of living generic types. They are distributed all over the world, including the Australian region, and, being small and often nocturnal, and by no means particular in their diet, have managed to thrive and multiply to a greater extent than any other group of living mammals. They are chiefly terrestrial creatures, and often burrow or live in ready-made burrows.Some, however, such as the Voles, are aquatic; others,e.g.the Squirrels, are arboreal, and there are "flying" Rodents exemplified by the genusAnomalurus. Their range of habitat is in fact as wide as that of any other Order of mammals, and wider than that of most.