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Hylobates lar
white-handed gibbon


By Andrea Smith

Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Class: Mammalia
Order: Primates
Family: Hylobatidae
Genus: Hylobates
Species: Hylobates lar

Geographic Range

Hylobates lar is found in the tropical rainforests of southern and S.E. Asia, including Thailand, Malaysia, Indonesia, and the area encompassing Southern China to Eastern Burma.

Biogeographic Regions
oriental (Native )

Habitat

This species is found in the tropical rainforest, where it occupies only the upper canopy. These gibbons rarely, if ever, descend to the forest floor. This fact alone makes them very hard to study.

Habitat Regions
tropical ; terrestrial

Terrestrial Biomes
rainforest

Physical Description

Range mass
4.5 to 6 kg
(9.91 to 13.22 lb)

Hylobates lar weighs 5.5 kg on average. Individuals are either dark brown to black in color, or red buff color with white face-rings, hands, and feet. Colors are not specific to sex. Males and females can show either color, but their white "accents" are always present.

Other Physical Features
endothermic ; homoiothermic; bilateral symmetry

Sexual Dimorphism
sexes alike

Reproduction

Lar gibbons are monogamous.

Mating System
monogamous

Breeding interval
Females produce approximately one young every two years.

Breeding season
These gibbons breed year round.

Range number of offspring
1 to 2

Average number of offspring
1

Average number of offspring
1
[External Source: AnAge]

Average gestation period
7 months

Average gestation period
217 days
[External Source: AnAge]

Average birth mass
307.2 g
(10.83 oz)
[External Source: AnAge]

Average time to weaning
24 months

Average age at sexual or reproductive maturity (female)
8 years

Average age at sexual or reproductive maturity (female)
Sex: female

2555 days
[External Source: AnAge]

Average age at sexual or reproductive maturity (male)
8 years

Average age at sexual or reproductive maturity (male)
Sex: male

1825 days
[External Source: AnAge]

Gibbons have no fixed season for breeding. The gestation period lasts around seven months, and females produce approximately one young every two years. Young are weaned by the time they are about two years old. In most gibbons, reproductive maturity is reached around 8 years of age. Although they are probably completely capable of caring for themselves at an earlier age, young gibbons do not leave their family group until they reach sexual maturity.

Key Reproductive Features
iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); fertilization ; viviparous

Although infants are weaned within a two year period, young stay with the family group for a few additional years. Although the bulk of parental care, including nursing and grooming, is the responsibility of the mother, the father and older siblings also help out.

Parental Investment
altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Male, Female); pre-weaning/fledging (Provisioning: Female, Protecting: Male, Female); pre-independence (Provisioning: Female, Protecting: Male, Female); post-independence association with parents; extended period of juvenile learning

Lifespan/Longevity

Average lifespan
Sex: male
Status: captivity

40.0 years
[External Source: Max Planck Institute for Demographic Research]

Average lifespan
Sex: female
Status: captivity

40.0 years
[External Source: Max Planck Institute for Demographic Research]

Average lifespan
Status: wild

25.0 years
[External Source: Max Planck Institute for Demographic Research]

Average lifespan
Status: captivity

31.5 years
[External Source: Max Planck Institute for Demographic Research]

Data are not available for this species, but other members of the genus Hylobates are known to reach ages of 44 years in captivity. Wild individuals are thought to live around 25 years. It is likely that H. lar is like other members of the genus in terms of its lifespan.

Behavior

These gibbons form small groups consisting of one mated pair and their offspring. Mated pairs tend to stay together in the same territory for their entire life-span, and they continue to have new young as mature offspring leave the group. There is some evidence of "divorces," where the male or female leaves his or her mate for no obvious reason and mates with another individual.

All gibbons are known to defend their territories from conspecifics using calls. These calls are usually very loud, and typically are duets, with both males and females calling.

Key Behaviors
arboreal ; diurnal ; sedentary ; territorial ; social

Communication and Perception

As in all species of gibbon, these animals use vocalizations to defend their territorial boundaries. In addition to these vocal communications, primates are known to use a variety of visual signals, such as facial expressions and body postures, to communicate. Tactile communication, such as grooming and playing, is important within the family unit.

Communication Channels
visual ; tactile ; acoustic

Other Communication Modes
duets

Perception Channels
visual ; acoustic

Food Habits

Lar gibbons are one of the pickiest eaters in the primate world. They are mainly frugivores, but they will also eat other plant matter. They consume ripe fruit only, and only new leaves and buds. They have several adaptations for feeding. One of them is brachiating locomotion, which involves swinging from branch to branch by their arms. This style of motion allows them to reach the periphery of the tree canopy, where most of their food is found. Other adaptations include high cusps on their back teeth to help grind plant matter, and a gut adapted for a folivorous diet.

Plant Foods
leaves; fruit; flowers

Predation

Incidents of predation on these animals have not been recorded. It is likely that because they inhabit the upper canopy, they do not often fall victim to terrestrial predators like leopards. Any predators they do have must be able to reach them in the canopy, where the thin tree brances do not permit heavier animals to travel. Because of this, it seems that to the extent that predation occurs, these animal fall victim to raptors.

Ecosystem Roles

As frugivores, these animals are probably important in seed dispersal.

Ecosystem Impact
disperses seeds

Economic Importance for Humans: Positive

Lar gibbons do not play a very important role economically. They provide some food for humans, but not on a large scale. Although many primates are used for biomedical reasearch, gibbons are not often used for this purpose. They are occasionally captured for the pet trade.

Positive Impacts
pet trade ; food

Economic Importance for Humans: Negative

Hylobates lar is not known to have any negative impact on humans.

Conservation Status

IUCN Red List [Link]
Lower Risk - Near Threatened

US Federal List [Link]
No special status

CITES [Link]
Appendix I

This species is threatened for a several reasons. These gibbons are hunted for meat in some areas. Live capture for the pet trade also poses a serious problem. In many Asian countries, it is "fashionable" to own your own primate, and this has led to the death of many gibbons either at the time of capture or during transport. The final, and greatest, threat to these gibbons is deforestation. Rainforests are disappearing at an alarming rate due to logging and agricultural, leaving forest species with an ever smaller region in which to live. Some efforts are being made to save these primates, such as national parks and reserves, but they are not very effective. Laws protect them from live capture, but they are rarely enforced. Listed in CITES Appendix 1.

For More Information

Find Hylobates lar information at

Contributors

Nancy Shefferly (editor), Animal Diversity Web Staff.

Andrea Smith (author), University of Michigan.

References

Tuttle, R. H. 1986. Apes of the World. Noyes Publications, New Jersey.

Rodman, P.S., and Cant, J.G.H. 1984. Adaptations for Foraging in Nonhuman Primates. Columbia University Press, NY.

Wolfheim, J.H. 1983. Primates of the World: Distribution, Abundance, and Conservation.

University of Washington Press, Washington D.C.

To cite this page: Smith, A. 1999. "Hylobates lar" (On-line), Animal Diversity Web. Accessed February 12, 2012 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Hylobates_lar.html

Disclaimer: The Animal Diversity Web is an educational resource written largely by and for college students. ADW doesn't cover all species in the world, nor does it include all the latest scientific information about organisms we describe. Though we edit our accounts for accuracy, we cannot guarantee all information in those accounts. While ADW staff and contributors provide references to books and websites that we believe are reputable, we cannot necessarily endorse the contents of references beyond our control.

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