Asian fauna

Asia's geographical location and its links not only with Europe but in the recent past with Africa, North America, and Australasia have provided abundant opportunities for plant and animal colonization. Thus the Asiatic fauna includes species having close affinities with neighbouring continents. Examples are the wild sheep common to both Asia and North America; the elk, lynx, wolf, and wolverine common to Europe, Asia, and Canada; the pangolins and prosimians, as well as the cheetah, leopard, and lion common to Asia and Africa, to mention only a few. It is therefore hardly surprising that the Asiatic fauna is highly diversified. It is best considered in terms of the vegetational zones into which the continent can very roughly be divided.

The northernmost zone, the tundra, bears only a sparse and stunted vegetation and has permanently frozen subsoil (permafrost). Most animals occupy the tundra only seasonally, moving south at the approach of winter. The reindeer is one of the few permanent residents. The principal large hoofed animal of the tundra is the elk. Carnivores include the brown bear, wolf, wolverine, and arctic fox, as well as the marten and sable. Rodents include lemmings and flying squirrels. Among the birds, the snowy owl and the willow ptarmigan are permanent residents. The hordes of insects that proliferate during the brief summer attract large numbers of seasonal migrant birds.

The tundra merges into the taiga, a belt of mainly coniferous forest reaching across the continent, to form the largest continuous block of forest in the world. Approaching the Pacific coast the character of the taiga gradually changes to a mixture of deciduous trees, comparable to the broadleaved woodlands of Europe. Among the animals of this region are some that resemble those of Europe, others from various parts of Asia. They include several species of deer (red and roe among them), goral (one of the ‘goat-antelopes’), bear, leopard, even a monkey (the Japanese macaque). The tiger – largest and most powerful of living carnivores – probably originated in this region before radiating south and west to its present restricted range.

Steppe South of the tundra, forest gives way to treeless steppe – the Eurasian equivalent of prairie and pampas – merging in places into desert. The steppe is characterised by a climate ranging from extreme winter cold to great summer heat. Many species overcome the problem of climatic variation by being strongly nomadic. Key mammals are the burrowing rodents such as marmots, lemmings, and mice, both in maintenance of habitat and as the principal prey species for a host of predatory mammals and birds. At one time the steppe carried immense herds of gregarious herbivores including wild ass, wild horse, wild camel, saiga antelope, and goitred gazelle, but as the grasslands are also utilised with increasing intensity by pastoral humans and their domestic livestock, the wild species have inevitably declined, some almost to the point of extinction.

Innumerable lakes and other wetlands are a prominent feature of the steppe. These are of crucial importance for wildfowl, not only for breeding but also as assembly areas for migratory birds. The complex of lakes includes Lake Baikal, the world's oldest and deepest lake. Its waters contain an unusually interesting fauna, including more than 20 species of fish not found anywhere else and a unique species of seal – the only full species of seal wholly confined to fresh water.

The high plateauland of Central Asia is home to several species that are distinguished by their adaptation to severe cold. Mammals include the Tibetan gazelle, wild ass, the snow leopard, and its principal prey the bharal or blue sheep. Of particular interest are the wild yak and the Tibetan antelope, or chiru, which habitually live at heights of up to 6,100 m/20,000 ft above sea-level, higher than any other large mammal. The wild yak is one of a group of Asiatic wild cattle that have radiated into a variety of ecological niches. Besides the extinct aurochs and the bison, these include the buffalo, banteng, gaur, and kouprey, as well as two dwarf forms, the anoa of Sulawesi and the tamaraw of the Philippines. A link between wild cattle and wild sheep is provided by the ox-sheep (Ovibovini), takin, and musk ox. Other interesting groups include the goat-antelopes (Rupicaprini), represented by the goral and the serow, which together with the Rocky Mountain goat of North America and the chamois of Europe constitute a link between the goats and the antelopes. Goats are particularly well represented in Asia; species include the tahr, ibex, tur, bharal, markhor, red sheep, and argali.

Southeast Asia Sichuan, where the eastern extremities of the Tibetan plateau descend into China, is an area of exceptional zoological interest and importance. It is not only a transitional zone between the Palaeoarctic and Oriental regions, but also the repository for a number of ancient species, including the giant panda (held by some to be an aberrant bear), and a group of ancient insectivores that have adapted to an aquatic way of life, some to the extent of acquiring webbed feet. Here, too, is probably the ancestral home of the pheasant.

The Himalayas form a natural division between the Palaeoarctic and Oriental regions. To the south, many species are similar to those found in Africa, with grassland herbivores such as the chinkara gazelle and predators including the lion, cheetah, hyena, and jackal. Forest animals include the elephant and three species of rhinoceros. The ant-eating niche is occupied by the pangolins, which are also found in Africa.

Primates Asia's tropical forests accommodate one of the world's three principal primate communities, about 45 species including prosimians (the loris and tarsier), the leaf-eating langurs, the orang-utan of Borneo and Sumatra, and the gibbon. Extremes of specialization are reached by the snub-nosed monkey, which has left the warm forests usually preferred by primates to live in a habitat lying under snow for about half the year, and by the proboscis monkey, which has adapted to life in mangrove swamps, in the process becoming a competent diver and swimmer.