Agile Gibbon (Hylobates agilis)

MORPHOLOGY:
Pelage color for the agile gibbon ranges from buffy colored to reddish-brown, and can even be of a brown or black color. Males differ from the females in having both white eyebrows and cheeks while the females only have white eyebrows. This species has relatively long forearms which assist it in suspensory behavior. This species has throat sac located beneath the chin to help enhance the calls. The agile gibbon lacks a tail, caudal vertebrae. The average body mass for an adult male agile gibbon is around 5.8 kilograms, and for the female it is around 5.4 kilograms (Fleagle, 1988).

RANGE:
The agile gibbon is found in the countries of Indonesia, Malaysia, and Thailand. This species is found in semideciduous monsoon forests and tropical evergreen forests. The agile gibbon prefers the upper canopy of the forest.

ECOLOGY:
The agile gibbon is a frugivorous species, but will also consume immature leaves and insects. The agile gibbon prefers to consume fruits high in sugar such as the fig (Ficus). This species forages for fruit in the middle canopy of the forest and for immature leaves in the middle and upper canopies. This an arboreal and a diurnal species. This species sleeps and rests in the emergent trees (Leighton, 1987).

LOCOMOTION:
The agile gibbon is a true brachiator which means it moves by suspensory behavior (Fleagle, 1988). The brachiation is of a type where the agile gibbon throws itself from tree to tree over gaps of 10 meters or more using there arms (Fleagle, 1988). This species also climbs when moving slowly and feeding (Fleagle, 1988). This species is also able to move for short distances by bipedalism (Fleagle, 1988).

SOCIAL BEHAVIOR:
The agile gibbon has a monogamous mating and social system. The basic group structure is the breeding pair and their offspring. Both males and females emigrate from their natal group around adolescence. This is a territorial species. Adolescent and subadult males participate in the defending of the territory against conspecific males with their fathers (Gittins, 1980).

VOCAL COMMUNICATION:
duetting: These are vocalizations which occur between the breeding male and female, and is dominated by the female. This vocalization is important because it helps to maintain the pair bond between the breeding pair and also it helps to establish and maintain the territory.

OLFACTORY COMMUNICATION:

VISUAL COMMUNICATION:

TACTILE COMMUNICATION:
social grooming: This is when one individual grooms another and is used to reinforce the bonds between individuals.

REPRODUCTION:
The agile gibbon gives birth to a single offspring.

REFERENCES:
Burton, Frances. 1995. The Multimedia Guide to the Non-human Primates. Prentice-Hall Canada Inc.

Fleagle, John G. 1988. Primate Adaptation and Evolution. Academic Press.

Gittins, S.P. 1980. Territorial Behavior in the Agile Gibbon. International Journal of Primatology, Vol. 1, 381-399.

Leighton, D.R. 1987. Gibbons: Territoriality and Monogamy. In Primate Societies. eds. B.B. Smuts, D.L. Cheney, R.M. Seyfarth, R.W. Wrangham, and T.T. Struhsaker. University of Chicago Press.

Last Updated: October 8, 2003.
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