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Agile Gibbon

Local name: 
Ungko
Scientific name: 

Hylobates agilis

Status: 
Endangered

Agile Gibbon

Distribution:
Agile gibbons are primarily found in central and south Sumatra but can also be found in Peninsular Malaysia and south Thailand.
Population size:
Very little information exists on the population and demographic trends of the species, although it is said to be more at risk in the Sumatran part of its range where it is thought to be declining rapidly.
Characteristics:
The fur colouring of agile gibbons can range from a pale buff colour to dark brown or black. Both males and females have white eyebrows but usually males have white cheeks as well. Juveniles have a white ring around their face. The average body weight for a male is 5.8kg and the female is slightly smaller at 5.4kg. Like all gibbon species they have no tail and have long arms for brachiating (using their arms swing from branch to branch).
Habitat:
Agile gibbons can range from lowland forest to hill, sub-montane and montane forest. They show a preference for habitats with high numbers of large dipterocarp tree species.
Ecology:
The main part of their diet is made up of fruit, especially figs, but they are also known to eat young leaves and insects. Agile gibbons are diurnal and they sleep and rest in large emergent tree species. Groups are normally made up of a monogamous pair and their offspring. The female gives birth to one offspring after a seven month gestation period. Both male and female offspring will move away from the family group at around eight years old. They are a territorial species and use morning calls to establish and maintain the territory. The long call is dominated by the female and also serves to maintain the bond between the pair.
Threats:
The main threats to this species are the conversion of their forest habitat to oil palm plantations and the capture of individuals for the illegal pet trade.
At Harapan Rainforest:
Agile Gibbon groups are found throughout Harapan Rainforest and research is currently being conducted to assess their abundance and distribution throughout the site. This work is being funded by the US. Fish and Wildlife Service.
Interesting facts:
  • The Agile Gibbon although normally found high up in the tree can also move short distances bipedally (using two legs) on the forest floor by holding their arms up in the air for balance.
  • If the singing doesn’t deter other gibbon groups, they will chase away intruders.
  • Gibbons do not build nests. They sleep sitting on a branch with their arms wrapped around their knees and head tucked into their lap.
  • Gibbons are the only monogomous ape (apart from humans).
 
 

For further information please look at the following sites:
 
IUCN Red List
Gibbon Research Lab and Gibbon Network
The Gibbon Conservation Alliance