The most aberrant representative of the thooid series is the African hunting-dog (Lycaon pictus, fig. 5), which differs from the other members of this series by the teeth being rather more massive and rounded, the skull shorter and broader, and the presence of but four toes on each limb, as in Hyena. The hunting-dog, from south and east Africa, is very distinct externally from all other Canidae; being nearly as large as a mastiff, with large, broadly ovate erect ears and a singular colouring, often consisting of unsymmetrical large spots of white, yellow and black. It presents some curious superficial resemblances to Hyena crocuta, perhaps a case of mimetic analogy, and hunts its prey in large packs. Several local races, one of which comes from Somaliland, differing in size and colour, are recognized (see [Hunting-Dog]). Nearly related to the hunting-dog are the dholes or wild dogs of Asia, as represented by the Central Asian Cyan primaevus and the Indo-Malay C. javanicus. They have, however, five front-toes, but lack the last lower molar; while they agree with Lycaon and Speothos in that the heel of the lower sectorial tooth has only a single compressed cutting cusp, in place of a large outer and a smaller inner cusp as in Canis. Dholes are whole-coloured animals, with short heads; and hunt in packs. The bush-dog (Speothos, or Icticyon venaticus) of Guiana is a small, short-legged, short-tailed and short-haired species characterized by the molars being only 2 or 1⁄2; the carnassial having no inner cusp. The long-haired raccoon-dog (Nyctereutes procyonoides) of Japan and China agrees essentially in everything but general appearance (which is strangely raccoon-like) with Canis. The typical group of the latter includes some of the largest members of the family, such as the true wolves of the northern parts of both Old and New Worlds (C. lupus, &c.), and the various breeds of the domestic dog (C. familiaris), the origin of which is still involved in obscurity. Some naturalists believe it to be a distinct species, descended from one that no longer exists in a wild state; others have sought to find its progenitors in some one of the wild or half-wild races, either of true dogs, wolves or jackals; while others again believe that it is derived from the mingling of two or more wild species or races. It is probably the earliest animal domesticated by man, and few if any other species have undergone such an extraordinary amount of variation in size, form and proportion of limbs, ears and tail, variations which have been perpetuated and increased by careful selective breeding (see [Dog]). The dingo or Australian dog is met with wild, and also as the domestic companion of the aboriginal race of the country, by whom it appears to have been originally introduced. It is nearly related to a half-wild dog inhabiting Java, and also to the pariah dogs of India and other eastern countries. Dogs were also in the possession of the natives of New Zealand and other islands of the Pacific, where no placental mammals exist naturally, on their discovery by Europeans in the 18th century. The slender-jawed C. simensis of Abyssinia and the South American C. jubatus and C. antarcticus are also generally placed in this group. On the other hand, the North American coyote (C. latrans), with its numerous subspecies, and the Old World jackals, such as the Indo-European C. aureus the Indian C. pallipes, and the African C. lupaster, C. anthus, C. adustus, C. variegatus and C. mesomelas (the black-backed jackal), although closely related to the wolves, have been placed in a separate group under the name of Lupulus. Again, Thous (or Lycalopex), is a group proposed for certain South American Canidae, locally known as foxes, and distinguished from all the foregoing by their fox-like aspect and longer tails, although with skulls of the thöoid type. Among these are the bright-coloured colpeo, C. magellanicus, the darker C. thous, C. azarae, C. griseus, C. cancrivorus and C. brasiliensis. Some of these, such as C. azarae and C. griseus, show a further approximation to the fox in that the pupil of the eye forms a vertical slit. More distinct from all the preceding are the members of the alopecoid or vulpine section, which are unknown in South America. The characteristic feature of the skull has been already mentioned. In addition to this, reference may be made to the elliptical (in place of circular) pupil of the eye, and the general presence of ten (rarely eight) teats instead of a smaller number. The typical groups constituting the subgenus (or genus) Vulpes, is represented by numerous species and races spread over the Old World and North America. Foremost among these is the European fox (C. vulpes—otherwise Vulpes alopex, or V. vulpes), represented in the Himalaya by the variety C. v. montanus and in North Africa by C. v. niloticus, while the North American C. pennsylvanicus or fulvus, can scarcely be regarded as more than a local race. On the other hand, the Asiatic C. bengalensis and C. corsac, and the North American C. velox (kit-fox) are smaller and perfectly distinct species. From all these the North American C. cinereo-argentatus (grey fox) and C. littoralis are distinguished by having a fringe of stiff hairs in the tail, whence they are separated as Urocyon. Again, the Arctic fox (C. lagopus), of which there is a blue and a white phase, has the tail very full and bushy and the soles of the feet thickly haired, and has hence been distinguished as Leucocyon. Lastly, we have the elegant little African foxes known as fennecs (Fennecus), such as C. zerda and C. famelicus of the north, and the southern C. chama, all pale-coloured animals, with enormously long ears, and correspondingly inflated auditory bullae to the skull (see [Wolf], [Jackal], [Fox]).
Whatever differences of opinion may obtain among naturalists as to the propriety of separating generically the foxes from the wolves and dogs, there can be none as to the claim of the long-eared fox (Otocyon megalotis) of south and east Africa to represent a genus by itself. In this animal the dental formula is i. 3⁄3, c. 1⁄1, p. 4⁄4, m. 3 or 4⁄4; total 46 or 48. The molar teeth being in excess of almost all other placental mammals with a differentiated series of teeth. They have the same general characters as in Canis, with very pointed cusps. The lower sectorial shows little of the typical character, having five cusps on the crown-surface; these can, however, be identified as the inner tubercle, the two greatly reduced and obliquely placed lobes of the blade, and two cusps on the heel. The skull generally resembles that of the smaller foxes, particularly the fennecs. The auditory bullae are very large. The hinder edge of the lower jaw has a peculiar form, owing to the great development of an expanded, compressed and somewhat inverted subangular process. Vertebrae: C. 7, D. 13, L. 7, S. 3, Ca. 22. Ears very large. Limbs rather long, with the normal number of toes. The two parietal ridges on the skull remain widely separated, so that no sagittal crest is formed. The animal is somewhat smaller than an ordinary fox. In the year 1880 Professor Huxley suggested that in the long-eared fox we have an animal nearly representing the stock from which have been evolved all the other representatives of the dog and fox tribe. One of the main grounds for arriving at this conclusion was the fact that this animal has very generally four true molars in each jaw, and always that number in the lower jaw; whereas three is the maximum number of these teeth to be met with in nearly all placental mammals, other than whales, manatis, armadillos and certain others. The additional molars in Otocyon were regarded as survivals from a primitive type when a larger number was the rule. Palaeontology has, however, made great strides since 1880, and the idea that the earlier mammals had more teeth than their descendants has not only received no confirmation, but has been practically disproved. Consequently Miss Albertina Carlsson had a comparatively easy task (in a paper published in the Zoologisches Jahrbuch for 1905) in demonstrating that the long-eared fox is a specialized, and to some extent degraded, form rather than a primitive type. This, however, is not all, for the lady points out that, as was suggested years previously by the present writer, the creature is really the descendant of the fossil Canis curvipalatus of northern India. This is a circumstance of considerable interest from a distributional point of view, as affording one more instance of the intimate relationship between the Tertiary mammalian fauna of India and the existing mammals of Africa.
In regard to the members of the dog-tribe as a whole, it may be stated that they are generally sociable animals, hunting their prey in packs. Many species burrow in the ground; none habitually climb trees. Though mostly carnivorous, feeding chiefly on animals they have chased and killed themselves, many, especially among the smaller species, eat garbage, carrion, insects, and also fruit, berries and other vegetable substances. The upper surface of the tail of the fox has a gland covered with coarse straight hair. This gland, which emits an aromatic odour, is found in all Canidae, with possibly the exception of Lycaon pictus. Although the bases of the hair covering the gland are usually almost white, the tips are always black; this colour being generally extended to the surrounding hairs, and often forming dark bars on the buttocks. The dark spot on the back of the tail is particularly conspicuous, notably in such widely separated species as the wolves, Azara’s dog and the fennec.
Although its existing representatives are very different, the bear-family or Ursidae, as will be more fully mentioned in the sequel, was in past times intimately connected with the Canidae. In common with the next two families, the modern Bear tribe. Ursidae are characterized by the very small tympanic bulla, and the broad paroccipital process, which is, however, independent of the bulla. The feet are more or less completely plantigrade and five-toed. The intestine has neither duodeno jejunal flexure nor a caecum; the prostate gland is rudimentary; but glands occur in the vasa deferentia; and the penial bone is cylindrical. As distinctive characteristics of the Ursidae, may be mentioned the presence of an alisphenoid canal on the base of the skull; the general absence of a perforation on the inner side of the lower end of the humerus; the presence of two pairs of upper and three of lower molars, which are mostly elongated and low-cusped; and the non-cutting character and fore-and-aft shortening of the upper sectorial, which has no inner root and one inner cusp (fig. I, III.). Anal glands are apparently wanting. The short tail, bulky build, completely plantigrade feet and clumsy gait are features eminently characteristic of the bears.
The great majority of existing bears may be included in the typical genus Ursus, of which, in this wide sense, the leading characteristics will be as follows. The dentition is i. 3⁄3, c. 1⁄1, p. 4⁄4, m. 2⁄3 = 42; but the three anterior premolars, above and below, are one-rooted, rudimentary and frequently wanting. Usually the first (placed close to the canine) is present, and after a considerable interval the third, which is situated close to the other teeth of the cheek-series. The fourth (upper sectorial) differs essentially from the corresponding tooth of other Carnivora in that the inner lobe is not supported by a distinct root; its sectorial characters being very slightly marked. The crowns of both true molars are longer than broad, with flattened, tuberculated, grinding surfaces; the second having a large backward prolongation or heel. The lower sectorial has a small and indistinct blade and greatly developed tubercular heel; the second molar is of about the same length, but with a broader and more flattened tubercular crown; while the third is smaller. The milk-teeth are comparatively small, and shed at an early age. The skull is more or less elongated, with the orbits small and incomplete behind, and the palate prolonged considerably behind the last molar. Vertebrae: C. 7, D. 14, L. 6, S. 5, Ca. 8-10. Body heavy. Feet broad, completely plantigrade; the five toes on each well developed, and armed with long compressed and moderately curved, non-retractile claws, the soles being generally naked. Tail very short. Ears moderate, erect, rounded, hairy. Fur generally long, soft and shaggy.
Bears are animals of considerable bulk, and include among them the largest members of the order. Though the species are not numerous, they are widely spread over the earth, although absent from Africa south of the Sahara and Australasia. As a rule, they are omnivorous, or vegetable feeders, even the polar bear, which subsists for most of the year on flesh and fish, eating grass in summer. On the other hand, many of the brown bears live largely on salmon in summer. Among the various species the white polar bear of the Arctic regions, Ursus (Thalassarctus) maritimus, differs from the rest by its small and low head, small, narrow and simple molars, and the presence of a certain amount of hair on the soles of the feet. The typical group of the genus is represented by the brown bear (U. arctus) of Europe and Asia, of which there are many local races, such as the Syrian U. a. syriacus, the Himalayan U. a. isabellinus, the North Asiatic U. a. collaris, and the nearly allied Kamchadale race, which is of great size. In Alaska the group is represented by huge bears, which can scarcely claim specific distinctness from U. arctus; and if these are ranked only as races, it is practically impossible to regard the Rocky Mountain grizzly bear (U. horribilis) as of higher rank, although it naturally differs more from the Asiatic animal. On the other hand, the small and light-coloured U. pruinosus of Tibet may be allowed specific rank. More distinct is the North American black bear U. americanus, and its white relative U. kermodei of British Columbia; and perhaps we should affiliate to this group the Himalayan and Japanese black bears (U. torquatus and U. japonicus). Very distinct is the small Malay sun-bear U. (Helarctus) malayanus, characterized by its short, smooth fur, extensile tongue, short and wide head, and broad molars. Finally, the spectacled bear of the Andes, U. (Tremarctus) ornatus, which is also a broad-skulled black species, differs from all the rest in having a perforation, or foramen, on the inner side of the lower end of the humerus. A second genus, Melursus, represented by the Indian sloth-bear (M. ursinus), differs from the preceding in having only two pairs of upper incisors, the small size of the cheek-teeth, and the extensile lips. Ants, white-ants, fruits and honey form the chief food of this shaggy black species,—-a diet which accounts for its feeble dentition (see [Bear]).
| Fig. 6.—The Parti-coloured Bear, or Giant Panda (Aeluropus melanoleucus). |
The parti-coloured bear or giant panda (Aeluropus melanoleucus, fig. 6) of eastern Tibet and north-west China forms in some degree a connecting link between the bears and the true panda, although placed by Professor E.R. Lankester in the same family as the latter. In the number of the teeth, and to some extent in the character of the molars, as well as in the abbreviated tail, Aeluropus resembles the bears, but in the structure of the sectorial tooth, the presence of an extra radial carpal bone, and the osteology generally, it is more like the panda. In the absence of an alisphenoid canal to the skull it differs both from the latter and the bears, and thereby resembles the raccoons; while in having a perforation at the lower end of the humerus, it agrees with the spectacled bear, the panda and raccoons. The dentition is i. 3⁄3, c. 1⁄1, p. 4⁄3, m. 2⁄3; total 40; premolars increasing in size from first to last, and two-rooted except the first; the first upper molar with quadrate crown, broader than long; and the second larger than the first. Skull with the zygomatic arches and sagittal crest immensely developed, ascending branch of lower jaw very high, giving great space for attachment of temporal muscle, and facial portion short. Bony palate not extending behind the last molar. No alisphenoid canal. Feet bear-like, but soles more hairy, and perhaps less completely plantigrade. Fur long and thick; and tail extremely short. Humerus with a perforation on the inner side of the lower end; a very large extra radial carpal bone. The colour of this strange animal is black and white (fig. 6).
With the panda (Aelurus fulgens) we reach an undoubted representative of the Procyonidae, or raccoon tribe, differing, however, from all the rest except the doubtful Aeluropus, in its Asiatic habitat. If the latter be included, the family may be defined as follows. Molars 3⁄2, except in Aeluropus, with blunt or sharp cusps; no alisphenoid canal, except in Aelurus; humerus generally with a foramen; feet plantigrade; tail, except in Aeluropus, long and generally ringed.
In the panda the dentition is i. 3⁄3, c. 1⁄1, p. 3⁄4, m. 2⁄2; total 38; the first lower molar being minute and deciduous, and the upper molars broad with numerous and complicated cusps. Vertebrae: C. 7, D. 14, L. 6, S. 3, Ca. 18. Skull high and compressed, with an alisphenoid canal, a short facial portion, and the ascending branch of the lower jaw, as in Aeluropus, very tall. Face cat-like, with moderate, erect, pointed ears. Claws blunt. Tail cylindrical and ringed. Fur long and thick. Extra radial carpal bone moderate. The panda is a bright golden red animal, with black under-parts, ranging from the eastern Himalaya to north-western China, where it is represented by a distinct race. Fossil species occur in the later Tertiary deposits of Europe (see [Panda]).