Indomalaya

Indomalaya, also known as the Oriental Realm in some biogeographic classifications, is one of the Earth’s eight biogeographic realms. It encompasses a large portion of South Asia and Southeast Asia, defined by distinctive assemblages of flora and fauna. The realm extends from the Indian subcontinent and Indochina through southern China to the Malay Peninsula and the major Indonesian archipelago west of the Wallace Line.

Geographically, Indomalaya includes tropical and subtropical regions with a predominance of monsoon climates. Its habitats range from tropical rainforests and mangroves to montane forests and, at higher elevations, temperate and alpine zones in the Himalayas and southern China. Lowland forests are often dominated by dipterocarps, while diverse ecosystems support a wide array of plants, birds, reptiles, and mammals. The region exhibits high biodiversity and many regional endemics, reflecting its varied topography and climate.

Fauna and flora in Indomalaya show a mix of widespread Asian lineages and regionally distinctive groups. Notable mammals include the Bengal tiger, Indian elephant, and Indian rhinoceros in the north, and the orangutans, gibbons, and proboscis monkeys of the Indonesian islands. The region also hosts diverse ungulates, primates, birds, and amphibians, with numerous endemic species and several biodiversity hotspots.

Etymology and classification notes that the name combines Indo- (Indian subcontinent) and Malaya (Malay region). Some schemes differ in boundary placement, particularly around Wallace’s Line, which separates Indomalayan fauna from Australasian faunal elements. The realm borders the Palearctic to the north and the Australasian/Oceanian regions to the southeast and east.