Wallace's line The important zoogeographical division which separates the Oriental and Notogean zoogeographical regions. AlfredWallace, a zoogeographer and contemporary of CharlesDarwin, first demarcated the boundary between the Oriental faunal region and the Australasian region with its distinctive marsupials and birds. The boundary, known to this day as Wallace's line, passes east of Java and Bali, northward through the Strait of Makassar (separating Borneo and Sulawesi), then extends eastward, south of Mindanao in the Philippines. There is a zone of mixing called ‘Wallacea’, and strictly the line defines the extreme western limit of Australasian mammals and the eastern limit of the main oriental fauna.

Wallace's line An important zoogeographical division which separates the Oriental and Australian faunal realms. Alfred Russel Wallace, a zoogeographer and contemporary of Charles Darwin, first demarcated the boundary, known to this day as ‘Wallace's line’, between the Oriental faunal realm and the Australian, with its distinctive marsupials (Marsupialia). This boundary passes east of Java and Bali, northward through the Strait of Makassar (separating Borneo and the Celebes), then extends eastward, south of Mindanao in the Philippines.

Wallace's line The important zoogeographical division which separates the Oriental and Notogean zoogeographical regions. Alfred Wallace, a zoogeographer and contemporary of Charles Darwin, first demarcated the boundary between the Oriental faunal region and the Australasian region with its distinctive marsupials. The boundary is known to this day as Wallace's line. There is a zone of mixing called ‘Wallacea’, and strictly the line defines the extreme western limit of Australasian mammals, and the eastern limit of the main Oriental fauna.

Wallace's line An imaginary line that runs between the Indonesian islands of Bali and Lombok and represents the separation of the Australian and Oriental faunas. It was proposed by the A. R. Wallace, who had noted that the mammals in Southeast Asia are different from and more advanced than their Australian counterparts. He suggested this was because the Australian continent had split away from Asia before the better adapted placental mammals evolved in Asia. Hence the isolated Australian marsupials and monotremes were able to thrive while those in Asia were driven to extinction by competition from placental mammals. See also zoogeography.

Wallace's line a hypothetical line, proposed by Alfred Russel Wallace, marking the boundary between the Oriental and Australian zoogeographical regions. Wallace's line is now placed along the continental shelf of SE Asia. To the west of the line Asian mammals such as monkeys predominate, while to the east of it the fauna is dominated by marsupials.