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 ; tactile ; acoustic ; chemical
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.
US Federal List: no special status
CITES: appendix i
IUCN Red List of Threatened Species: endangered
Hylobates lar is not known to have any negative impact on humans.
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
As frugivores, these animals are probably important in seed dispersal.
Ecosystem Impact: disperses seeds
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
Primary Diet: herbivore (Frugivore )
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 )
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
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.
Average lifespan
Sex: male
Status: captivity: 40.0 years.
Average lifespan
Sex: female
Status: captivity: 40.0 years.
Average lifespan
Status: wild: 25.0 years.
Average lifespan
Status: captivity: 31.5 years.
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.
Range mass: 4.5 to 6 kg.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: sexes alike
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.
Lar gibbons are monogamous.
Mating System: monogamous
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.
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 gestation period: 7 months.
Average weaning age: 24 months.
Average age at sexual or reproductive maturity (female): 8 years.
Average age at sexual or reproductive maturity (male): 8 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization ; viviparous
Average birth mass: 307.2 g.
Average gestation period: 217 days.
Average number of offspring: 1.
Average age at sexual or reproductive maturity (male)
Sex: male: 1825 days.
Average age at sexual or reproductive maturity (female)
Sex: female: 2555 days.
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
