Orang-utan (Pongo pygmaeus)
This family includes the Chimpanzees and Gorillas of Africa and the Orang-utan of Borneo and Sumatra, all large, intelligent tail-less primates. The Orang-utan differs from the other apes and monkeys in that adults lead a mostly solitary existence, although the ranges of several individuals may overlap.
Measurements: Largest male (above 15 years age) up to 1.4m tall, with a reach between the outstretched arms up to 2.4m, and weight 50-100 kg. Adult females much smaller, 35-50 kg. Independent (but immature, 7-10 years age) Orang-utans of both sexes 20-40 kg.
Identification: Coloration generally reddish-brown, varying from orange to dark reddish-brown in old individuals. Calls useful for identification in the field include something like a long belch, made by adult females, and loud roars, made by adult males, both by day and night. Often detected by its nests-a rough array of bent and broken twigs and small branches partially woven together. Orang-utans can sometimes also be detected by footprints on bare soil or discarded wedges of epiphytic fibres which they sometimes chew.
Ecology & Habitat: Diurnal and usually arboreal. Diet mainly fruits with young leaves and insects. Usually solitary, but young remain with mother until 5 or 6 years of age. Found in montane, secondary and swamp forests including nipah, but reaches highest densities (up to 2 individuals per sq.km.) in tall lowland dipterocarp forests-density in hill forest may be only 1 individual per 2 sq.km., sometimes enters gardens and plantations.
Distribution: Northern Sumatra, Borneo: P.p. pygmaeus. It seems likely that the Orang-utan was once distributed throughout most of Borneo up to about 1500 m and the present widespread but patchy distribution could be a result of hunting by man coupled with loss of forest habitat. There are orang-utan remains at all levels in cave deposits at Niah. A high altitude record of 2400 m is reported from Gunung Kinabalu but most records are from below 1000 m.