The Geographical Distribution of Animals, Volume 1 / With a study of the relations of living and extinct faunas as elucidating the past changes of the Earth's surface

by Alfred Russel Wallace

With very few exceptions, this vast territory is exposed to an extreme climate, inimical to animal life. All the lower parts being situated to the north, have an excessively cold winter, so that the limit of constantly frozen ground descends below the parallel of 60° north latitude. To the south, the land is greatly elevated, and the climate extremely dry. In summer the heat is excessive, while the winter is almost as severe as further north. The whole country, too, is subject to violent storms, both in summer and winter; and the rich vegetation that clothes the steppes in spring, is soon parched up and replaced by dusty plains. Under these adverse influences we cannot expect animal life to be so abundant as in those sub-regions subject to more favourable physical conditions; yet the country is so extensive and so varied, that it does actually, as we shall see, possess a very considerable and interesting fauna.

Mammalia.—Four genera seem to be absolutely confined to this sub-region, Nectogale, a peculiar form of the mole family (Talpidæ); Poephagus, the yak, or hairy bison of Thibet; with Procapra and Pantholops, Thibetan antelopes. Some others more especially belong here, although they just enter Europe, as Saiga, the Tartarian antelope; Sminthus, a desert rat;, and Ellobius, a burrowing mole-rat; while Myospalax, a curious rodent allied to the voles, is found only in the Altai mountains and North China; and Moschus, the musk-deer, is almost confined to this sub-region. Among the characteristic animals of the extreme north, are Mustela, and Martes, including the ermine and sable; Gulo, the glutton; Tarandus, the reindeer; Myodes, the lemming; with the lynx, arctic fox, and polar bear; and here, in the Post-pliocene epoch, ranged the hairy rhinoceros and Siberian mammoth, whose entire bodies still remain preserved in the ice-cliffs near the mouths of the great rivers. Farther south, species of wild cat, bear, wolf, deer, and pika (Lagomys) abound; while in the mountains we find wild goats and sheep of several species, and in the plains and deserts wild horses and asses, gazelles, two species of antelopes, flying squirrels (Pteromys), ground squirrels (Tamias), marmots, of the genus Spermophilus, with camels and dromedaries, probably natives of the south-western part of this sub-region. The most abundant and conspicuous of the mammalia are the great herds of reindeer in the north, the wolves of the steppes, with the wild horses, goats, sheep, and antelopes of the plateaus and mountains.

Among the curiosities of this sub-region we must notice the seal, found in the inland and freshwater lake Baikal, at an elevation of about 2,000 feet above the sea. It is a species of Callocephalus, closely allied to, if not identical with, one inhabiting northern seas as well as the Caspian and Lake Aral. This would indicate that almost all northern Asia was depressed beneath the sea very recently; and Mr. Belt's view, of the ice during the glacial epoch having dammed up the rivers and converted much of Siberia into a vast freshwater or brackish lake, perhaps offers the best solution of the difficulty.[^[9]]

Plate II.—Characteristic Mammalia of Western Tartary.—Several of the most remarkable animals of the Palæarctic region inhabit Western Tartary, and are common to the European and Siberian sub-regions. We therefore choose this district for one of our illustrative plates. The large animals in the centre are the remarkable saiga antelopes (Saiga Tartarica), distinguished from all others by a large and fleshy proboscis-like nose, which gives them a singular appearance. They differ so much from all other antelopes that they have been formed into a distinct family by some naturalists, but are here referred to the great family Bovidæ. They inhabit the open plains from Poland to the Irtish River. On the left is the mole-rat, or sand-rat (Spalax murinus). This animal burrows under ground like a mole, feeding on bulbous roots. It inhabits the same country as the saiga, but extends farther south in Europe. On the right is a still more curious animal, the desman (Myogale Muscovitica), a long-snouted water-mole. This creature is fifteen inches long, including the tail; it burrows in the banks of streams, feeding on insects, worms, and leeches; it swims well, and remains long under water, raising the tip of the snout, where the nostrils are situated, to the surface when it wants to breathe. It is thus well concealed; and this may be one use of the development of the long snout, as well as serving to follow worms into their holes in the soft earth. This species is confined to the rivers Volga and Don in Southern Russia, and the only other species known inhabits some of the valleys on the north side of the Pyrenees. In the distance are wolves, a characteristic feature of these wastes.

Plate II.

CHARACTERISTIC MAMMALIA OF WESTERN TARTARY.

Birds.—But few genera of birds are absolutely restricted to this sub-region. Podoces, a curious form of starling, is the most decidedly so; Mycerobas and Pyrrhospiza are genera of finches confined to Thibet and the snowy Himalayas; Leucosticte, another genus of finches, is confined to the eastern half of the sub-region and North America; Tetraogallus, a large kind of partridge, ranges west to the Caucasus; Syrrhaptes, a form of sand-grouse, and Lerwa (snow-partridge), are almost confined here, only extending into the next sub-region; as do Grandala, and Calliope, genera of warblers, Uragus, a finch allied to the North American cardinals, and Crossoptilon, a remarkable group of pheasants.

Almost all the genera of central and northern Europe are found here, and give quite a European character to the ornithology, though a considerable number of the species are different. There are a few Oriental forms, such as Abrornis and Larvivora (warblers); with Ceriornis and Ithaginis, genera of pheasants, which reach the snow-line in the Himalayas and thus just enter this sub-region, but as they do not penetrate farther north, they hardly serve to modify the exclusively Palæarctic character of its ornithology.

According to Middendorf, the extreme northern Asiatic birds are the Alpine ptarmigan (Lagopus mutus); the snow-bunting (Plectrophanes nivalis); the raven, the gyrfalcon and the snowy-owl. Those which are characteristic of the barren "tundras," but which do not range so far north as the preceding are,—the willow-grouse (Lagopus albus); the Lapland-bunting (Plectrophanes lapponica); the shore-lark (Otocorys alpestris); the sand-martin (Cotyle riparia), and the sea-eagle (Haliæetus albicilla).