Indo-Malaysian Region

Indo-Malaysian Region

 

or Oriental region, a zoogeo-graphic land area occupying the southern part of Asia and most of the islands between Asia and Australia. The northern border of the region begins on the coast of the Arabian Sea near the mouth of the Indus. It encompasses the Thar Desert and proceeds along the southern slope of the Himalayas, intersecting the upper courses of the great rivers of Southeast Asia to the north of the Indochinese Peninsula and proceeding toward the Pacific Ocean generally parallel to the course of the Yangtze or a little further to the north. Here, as in the west, its borders are poorly defined. The southern border includes Ceylon and the Malay Archipelago along a line between Bali, Lombok, and the Celebes Islands. The eastern limits encompass the Philippines, Hainan, Taiwan, and the Ryukyu Islands. This border is well defined; only the fauna of the Celebes Islands shares features of the Australian region (certain zoogeographers include them in the Australian region).

Extensive tropical forests are characteristic of the Indo-Malaysian region. In the north most of the territory is covered by mountains, but a small portion is desert (only in the extreme northwest) or savanna-type terrain (in the Deccan plateau), which has largely been replaced by cultivated areas. In certain regions cultivated terrain has replaced forest areas as well. The main type of fauna is the forest type, in which a significant role is played by arboreal and scansorial animals. Fauna of the Indo-Malaysian region is relatively old, having preserved some of the features of Miocene fauna (for example, elephants, rhinoceroses, tapirs, and mouse-deer). Given the richness and diversity of species and genera in fauna of the Indo-Malaysian region, the number of endemic groups of higher orders is relatively small. Four families of mammals are endemic to the region: tarsiers, cobegos (a special order), tree shrews, and gibbons. There are unique Insectivora, particularly hedgehogs, numerous bats, including phytophagous bats (kalongs); and several species of predators, including felines, various viverrines, and bears. Several characteristic ungulates are found, such as tapirs, rhinoceroses (3 species), deer, bovines (water buffalo and anoa, gaur, banteng, and kouprey), several species of antelope (nilgai, black buck, and four-horned antelope), and elephants. There are numerous rodents (including common squirrels and Russian flying squirrels) and several endemic species of monkeys, including orangutans. Freshwater dolphins inhabit certain rivers.

The number of species of birds is very great, but only the family of tufted swifts (Hemiprocnidae) and most species of broadbills (family Eurylaimidae) are endemic. Pittas, frogmouths, members of the order Galliformes, and certain other birds are developing uniquely. Widespread reptiles include geckoes, varanid and agamid lizards, skinks, snakes, and turtles, including those of the family Conopidae. There are several species of crocodiles (including gharials and alligators). Amphibia are not as diverse; the Candata order is not present. Numerous frogs, including flying frogs (Rhacophorus), are characteristic of amphibia. Tree frogs are found in small numbers. Fish are extremely varied. There are many varieties of carp and a number of species of catfish. Sharks inhabit large rivers.

In terms of historical relations the fauna of the Indo-Malaysian region is closest to that of the Ethiopian region. Rhinoceroses, elephants, monkeys of the Catarrhini suborder and anthropoid apes, lizards, certain types of lemurs, and certain genera of ungulates (for example, mouse-deer and water buffalo) are characteristic of both regions, as are birds such as peacocks and hornbills and reptiles such as chameleons and varanid and agamid lizards. Fauna sharply differs in various areas of the region. To a certain degree this has resulted from the insular nature of much of the territory, that is, unique forms of the limits of distribution areas. It is common practice to divide the IndoMalaysian region into two subregions, the Indo-Indochinese subregion and the Malaysian subregion.

Countries with ancient cultures, where several species of important farm animals were domesticated, are found within the Indo-Malaysian region. Such animals include the’water buffalo, gaur (the domesticated form is the gayal), banteng (“Bali cattle”), pig, hen, peacock, and Indian bee.

V. G. GEPTNER

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