The remainder of the island's rainforest is the only natural habitat for the endangered Bornean orangutan, which has long been nicknamed "the wild man of Borneo" for its human resemblance.
Over the centuries, Borneo's dense rainforest discouraged large-scale agriculture, though in recent years palm and rubber plantations have made great inroads.
Strictly Muslim, the Madurese began moving to Borneo in the 1960s as part of a government-backed relocation drive to relieve overcrowding in its own land.
Similar to New Guinea, Borneo has historically had two distinct populations.
Borneo's main range of mountains runs from southwest to northeast.
Borneo, the world's third-largest island, sits astride the Equator at the center of the Malay Archipelago, the Earth's largest group of islands.
The principal arteries of Borneo's commerce lie beside or on its rivers, even on those with strong currents descending from the mountains.
Borneo retains an image of exoticism and even darkness and dread in the popular mind.
Borneo by itself is one of the world's largest producers of tropical timber.
The whole of Borneo was controlled by the empire of Brunei during its golden age from the fifteenth to seventeenth centuries.
The dwindling sanctuary of the Asian elephant, the Sumatran rhinoceros, and the clouded leopard are also on Borneo.