Imágenes de páginas
PDF
EPUB

World we find the Magellanic Dog (Canis magellanicus), which extends to the very farthest extremity of the American continent, while in Southern Africa the Blackbacked Jackal (C. mesomelas) is met with in the vicinity of Cape Town, and in Australia the Dingo, now only known in a semi-domestic state, is found over the whole continent. But although, as we have shown, the genus Canis is so widely spread over all parts of the earth, the individual species are in some cases confined to restricted areas. Many well-known members of the genus—such as the Wolf, the Common Fox, and the Jackal—have a very wide distribution. But other species of Dog have limited ranges, and not more than two or three of them are usually met with in exactly the same district. Examples of this restricted distribution are afforded by the Maned Wolf (Canis jubata) of Brazil and Argentina, by the Corsac (Canis corsac) of Central Asia, and by several of the African Fennecs. But as a rule it may be taken that the various species of Dogs are hardy animals with extended areas of distribution.

Besides the genus Canis, the Dog family contains three other well-marked genera, each embracing but one species. One of these, the Bush-dog (Icticyon venaticus), is found only in Brazil and British Guiana, the two others, the Hunting-dog (Lycaon pictus) and the Long-eared Fox (Otocyon megalotis) are both peculiar to the Ethiopian Region, where the Lycaon appears to have a considerable range from north to south, but Otocyon is only known from the Cape Colony.

SECTION IV.—DISTRIBUTION OF THE BEAR-LIKE

CARNIVORA

We now come to the third and last division of the terrestrial Carnivora, which consists of those allied to the Bears and therefore denominated Arctoid. This division embraces three families—the Ursidæ, or Bears, which have a fairly wide distribution in both Hemispheres, the Procyonidæ, or Raccoons, which, with a single exception, are confined to the New World, and the Mustelidæ, or Weasels, which belong mostly to the Old World with a comparatively few representatives in the New World.

The Bears (Ursidæ), which head the group, contain, after the Cats, the largest and most destructive of the carnivorous animals of the present day. There has been a tendency of late days, unnecessarily, as we think, to augment the specific forms of the true Bears (Ursus). The species, recognizable by obvious external characters, do not appear to exceed ten in number. Taken as a whole the genus Ursus presents some very interesting features in its distribution. Its generic area embraces the whole of the Palæarctic and Nearctic Regions and extends into the northern confines of the Oriental. In the Ethiopian Region Ursus is entirely absent, and constitutes an important lipomorph. In the Neotropical Region it is represented by a single species, the Spectacled Bear (U. ornatus) of the Andes. In the extreme north of the globe the Polar Bear (U. maritimus) ranges round the Arctic Circle. The next northern species met with is the Brown Bear (U. arctos), which, under different forms and varieties, occupies the whole Palæarctic Region, and is represented in the Nearctic by: the scarcely distinct Grizzly Bear (U. horibilis) under various forms. A third species is the Black Bear of North America (U. americanus) which is represented in Japan by U. japonicus and throughout Central Asia by the Himalayan Bear (U. tibetanus). Finally, in the Oriental Region we meet with the Malayan Bear (U. malayanus), which is found not only in the Malay Peninsula but extends on one side into the islands of Sumatra, Java, and Borneo, and on the other side through Burma into North-eastern India. It is a curious fact that the Malayan Bear is entirely frugivorous, while its huge ally the Polar Bear, with exactly the same dentition, in all probability eats little else than flesh.

Besides the true Bear (Ursus), two other genera, each containing but a single species, must be placed in the same family. These are the Sloth Bear (Melursus) of India, which is restricted to the Indian Peninsula and Ceylon, and must be therefore regarded as a purely Oriental type, and the Æluropus (Æluropus melanoleucus), which occurs only in the high mountains of Eastern Tibet and must be attributed to the Palæarctic Region.

As already stated the Procyonidæ, or Raccoons, which embrace six genera and about nine species, are inhabitants of the New World with one singular exception. This is the peculiar Panda (Ælurus fulgens) of Nepaul, which, although at one time believed to belong to the Bear family, is now usually held to be most nearly related to the Raccoons of America. With this one exception the Raccoons

N

DISTRIBUT

THE ORDER CARNIVORA

Tod,

DISTRIBUTION OF THE ORDER CARNIVORA 249 are found only in the New World and mainly in the Neotropical Region, though as many as four species come within the limits of the Nearctic Region. The true Raccoons (Procyon) have a representative in each of the two Regions, while the Coatis (Nasua) and the Kinkajou (Cercoleptes) just come within the boundaries of the Nearctic Region from the south, and Bassariscus is restricted to Central America.

In the last family of terrestrial Carnivora belonging to the Arctoid division, we find a much more numerous group, the Mustelidæ, or Weasels, embracing about seventeen genera, represented by upwards of eighty different species. On the whole it may be said that the Mustelidæ are most abundant in the Nearctic, Palæarctic, and Oriental Regions, and less well represented in the Ethiopian and Neotropical Regions, while, like the rest of the Carnivores, except Canis, they are wholly absent in Australia. The eleven known Neotropical Mustelidæ belong to five genera, three of which are peculiar to this Region, while the two others, the Otters (Lutra) and the Weasels (Mustela), are both wide-ranging forms met with also in the Nearctic Region and broadly diffused in the Old World. It may be remarked, however, that Weasels (Mustela) do not occur in the Ethiopian Region, where, however, the Otters (Lutra) are represented by two species. The Nearctic Region is tenanted by several well-marked forms of the Musteline group, amongst which we may specify the Sea Otter (Latax), the Skunks (Mephitis and Spilogale), and the Glutton (Gulo); the last-mentioned type, however, being likewise found in the Palæarctic Region.

SECTION V.-DISTRIBUTION OF THE MARINE CARNIVORA

The Marine Carnivora, or Pinnipeds, which close the series of mammals of this order, are, as has already been shown, distributed on quite a different system from that which prevails in the terrestrial groups of mammals. As, however, they resort more or less to land for breeding purposes, the laws which regulate their distribution are more like those of terrestrial mammals than those which guide the distribution of such purely oceanic forms as the Cetaceans. We have already discussed the main facts of the distribution of the Pinnipeds in a former chapter of this work (Chapter VIII. sect. 2), and it is not now necessary to repeat them, further than to point out that of the three families comprised in this group the Otariide, or Sea-lions, are essentially Antarctic, only passing to the north in the Pacific where three species occur. On the other hand the Walruses (Trichechus), which are the sole constituents of the second family Trichechidæ, are still more absolutely Arctic, being only found in the North Atlantic and the North Pacific. The third family of Pinnipeds, of which about nine generic forms are recognized, are, on the other hand, much more widely diffused, though most prevalent in high and low latitudes and but feebly represented within the tropics. It should be also specially noted that the five known genera of Antarctic Phocidæ are quite different from those of the Arctic seas, although one of them (Macrorhinus) has wandered far up the coast of Western America to the shores of Southern California.

« AnteriorContinuar »