Dyak or Dayak (both: dī´ăk), name applied to one of the groups of indigenous peoples of the island of Borneo, numbering about 2 million. The Dyaks have maintained their customs and mode of life largely uninfluenced by modern civilization. The group is generally divided into the Sea Dyaks, or Iban, who inhabit the coastal areas and rivers; the Land Dyaks of SW Borneo; the Bahau of central and E Borneo; and the Ngadju of S Borneo. In Dyak communities, a few enormous longhouses provide dwelling places for a whole village. Each longhouse has a chief. In clearings made in the jungle, rice, yams, sugarcane, and other crops are grown cooperatively by the people of the entire community. Fishing and hunting (with blowguns and poison darts) supplement the food supply. Dyaks have highly complex animistic and shamanistic religious cults. Intertribal warfare has persisted, with headhunting as an important feature. In the second half of the 20th cent, Indonesia encouraged immigration to Kalimantan (Indonesian Borneo) from other areas of Indonesia, especially Madura. Tensions between the immigrants and the indigenous Dyaks have led to recurrent violence by Dyak tribesmen.
See B. Sandin, The Sea Dayaks of Borneo before White Rajah Rule (1968); D. Freeman, Report on the Iban (2d ed. 1970); R. Pringle, Rajahs and Rebels (1970).