Bornean Gibbon (Hylobates muelleri)

Family: HYLOBATIDAE

Gibbons are slender totally arboreal primates which, like other apes, lack a tail. They can travel very rapidly in canopy of rain forest, swinging by their long arms.

Measurement: HB 420-470, HF 128-150(7 specimens). Wt 5.0-6.4 kg.

Identification: Basically grey-brown but with a wide range in coat colour and pattern. No tail. Most often detected by the loud, bubbling call of the adult female, heard during the first hours of daylight and carrying for a distance of over 2 km under suitable conditions. H.m. funereus: usually mid grey-brown, with black underparts, and with a blackish "cap" on top of the head: sometimes nearly all black. Hands and feet coloured as the upperparts. A population of mixed colours occurs in the Lanjak-Entimau Wildlife Sanctuary in southern interior Sarawak.

Ecology & Habitat: Diurnal and completely arboreal. Unlike monkeys, gibbons usually cease activity about two hours before dusk. Usually found in small groups of one adult male, one adult female and one to three young. Each group depends on a territory of 20-30 ha. Diet consists of ripe fleshy fruits, young leaves and small insects. Normally found only in tall and selectively logged dipterocarp forests.

Distribution: Confined to Borneo in the lowlands and hills, up to 1500 m on Gunung Kinabalu. H.m. funereus: occurs in the north, south to the Saribas region of Sarawak and the S. Karangan region of East Kalimantan. H.m. muelleri: recorded between S. Barito and S. Karangan. H.m. abbotli recorded between the Saribas region and S.Kapuas in West Kalimantan.