Lesser apes in the family Hylobatidae are generally small. The average weight of H. agilis is 5.4 kg for females and 5.8 kg for males. Agile gibbons come in a variety of different colors, including black, brown, light tan and reddish-brown. Both sexes have white eyebrows. Males and females can be easily distinguished by the white eyebrows and cheeks possessed by the males.
Gibbons lack tails. Hylobates agilis, like other gibbons, has extremely long arms and fingers. This adaptation aides in brachiation, the prnciple mean of locomotion for these animals. Brachiation consists of hanging from branches and swinging from tree to tree.
Range mass: 4 to 6 kg.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: male larger
Habitat and Ecology
These arboreal and diurnal primates are primarily frugivorous (preferring fruits high in sugar, such as figs), but they will consume immature leaves and insects as well (Gittins 1979, 1982). An average home range size of 29 ha has been determined in a study at Sungai Dal (Gunung Bubu Forest Reserve) on the Malayan peninsula (Gittins 1979, 1982; Gittins and Raemaekers 1980).
Hylobates agilis is found in the tropical rainforests of Thailand, Malaysia, and Indonesia. They live in the upper canopy of the forest, feeding on fruits, leaves, and insects. Members of Hylobates spend most of their lives in the trees, and rarely descend to the ground.
Habitat Regions: tropical ; terrestrial
Terrestrial Biomes: rainforest
Hylobates agilis consumes large amounts of fruits. Like other gibbons, these animals are primarily frugivorous. Agile gibbons have also been observed eating a variety of other foods, including leaves, flowers, and insects. Due to their active lifestyle, it is necessary for them to eat food rich in calories. Fruits have a high caloric content.
Animal Foods: insects
Plant Foods: leaves; fruit; flowers
Primary Diet: herbivore (Frugivore )
As these animals are not likely to be an important source of food for other animals, their greatest role in the ecosystem is probably seed dispersal for the fruits they eat.
Ecosystem Impact: disperses seeds
Details on predation in this species are not available. However, snakes and raptors are probably the greatest threats to these animals. Because of their highly arboreal lifestyle, many potential predators are not likely to have access to these animals.
Life History and Behavior
Communication and Perception
As in all primates, communication in this species is complex and involved several different modalities.
As mentioned in the "Behavior" section, above, these animals are highly vocal, and use great call vocalizations to defend their territories from other mated pairs.
Tactile communication is also important, between mates, and between parents and their offspring. Tactile communication involves grooming, mating, play and sometimes aggression.
In addition to vocal and tactile forms of communication, these animals use facial expressions, gestures, and body postures to communicate with conspecifics.
Communication Channels: visual ; tactile ; acoustic
Other Communication Modes: duets
Perception Channels: visual ; acoustic
The reported lifespan in captivity for these lesser apes is 44 years. Wild animals probably do not live as long.
Status: captivity: 44 (high) years.
Status: captivity: 44.0 years.
Status: wild: 25.0 years.
Status: captivity: 28.0 years.
Lifespan, longevity, and ageing
Hylobates agilis forms monogamous bonds. Mated pairs stay together until one of them dies.
Mating System: monogamous
Hylobates agilis becomes sexually mature around the age of 8 years. The gestation period is about seven months. These animals give birth to a single offspring per pregnancy, and a mated pair can produce five to six offspring during their reproductive lifetime. The interbirth interval for H. agilis is around forty months.
Breeding interval: The interbirth period for H. agilis is around forty months.
Breeding season: These animals do not have a strict breeding season.
Average number of offspring: 1.
Average gestation period: 7 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 ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); fertilization ; viviparous
Average number of offspring: 1.
Most female gibbons nurse and care for their offspring until the offspring are about two years old. Offspring remain with their parents until they reach sexual maturity, around eight years, they then disperse from their natal group.
Males also particpate in parental care in this monogamous species. Males groom offspring, and help to defend them.
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
Molecular Biology and Genetics
Barcode data: Hylobates agilis
There are 2 barcode sequences available from BOLD and GenBank. Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species. See the BOLD taxonomy browser for more complete information about this specimen and other sequences.
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Download FASTA File
Statistics of barcoding coverage: Hylobates agilis
Public Records: 2
Specimens with Barcodes: 2
Species With Barcodes: 1
IUCN Red List Assessment
Red List Category
Red List Criteria
- 2000Lower Risk/near threatened
- 1996Lower Risk/near threatened
Hylobates agilis is listed by IUCN as an endangered species. Due to massive deforestation, their habitat is rapidly decreasing. This loss of habitat due to logging and agricultural demands is the main threat to gibbon species. Conservation measures have been taken, such as reserve game parks and breeding programs in zoos. Unfortunately, these measures are not enough, and more intense conservation efforts must be initiated in order to ensure the survival of these species.
US Federal List: endangered
CITES: appendix i
IUCN Red List of Threatened Species: endangered
Density estimates for this species range from 1.4-2.8 individuals/km2 in Bukit Barisan Seletan (O?Brien et al. 2004), and 6-11.4 individuals/km2 in Kerinci-Seblat (Yanuar 2001) to 5.5-18.9 individuals (2-5 groups)/km2 in Sungai Dal on the Malay peninsula (Gittins 1979). Recent surveys in south Thailand reveal the density to be 2 groups/km2 in parts of Hala Bala Wildlife Sanctuary (W. Brockelman pers. comm.)
The species? status in West Malaysia is uncertain; in Indonesia, it was certainly affected by fires and deforestation of the 1990s. There has been a probable 50%-plus range reduction in last 10 years (C. Groves pers. comm.), and oil palm plantations are expanding rapidly in the country. In Thailand there is extensive conversion of forests to rubber plantations and other crops (even inside protected areas), as well as hunting for the pet trade.
The species occurs in a number of protected areas, including Bukit Barisan National Park, Kerinci Seblat National Park, Selantan National Park, and Way Kambas National Park in Indonesia; Mudah Wildlife Reserve in Malaysia; and Hala Bala Sanctuary in Thailand. Unfortunately, many of these are merely proposed or gazetted, and their actual protected status is uncertain. Moreover, many of the Sumatran reserves are in montane regions where the species occurs only at low densities. In Bukit Barisan Selatan National Park in southwestern Sumatra, populations are presently secure and healthy but will depend on the regaining of control by the Indonesian government over illegal deforestation of its parks for their continued survival (O'Brien et al. 2004).
As the validity of the subspecies is questionable, a research priority is to clarify this issue so that the species can be further assessed.
Relevance to Humans and Ecosystems
Economic Importance for Humans: Negative
There is no known negative economic effect of this species on humans.
Economic Importance for Humans: Positive
Hylobates agilis is not an important economic resource for humans. These animals are sometimes hunted for food, and they are illegally captured for the pet trade. Poaching is a threat to H. agilis, for animals that are caught often die in transport from mishandling. Illegal poaching for meat and the pet trade are contributing factors in the declining numbers of H. agilis.
Positive Impacts: pet trade ; food
The agile gibbon (Hylobates agilis), also known as the black-handed gibbon, is an Old World primate in the gibbon family. It is found in Indonesia on the island of Sumatra, Malaysia, and southern Thailand. The species is listed as endangered on the IUCN Red List due to habitat destruction and the pet trade.
The species is generally thought not to have subspecies, but some experts recognise a mountain form and a lowland form.
The agile gibbon has fur varying in color from black to red-brown. Its brow is white, and the male can be recognized by its white or light-grey cheeks. Additionally, the male is slightly larger than the female. The agile gibbon weighs from 4 to 6 kg (8.8 to 13 lb) with an average of 5 kg (11 lb), though in captivity it can reach 8 kg (18 lb). It has a head and body length of 44–63.5 cm (17–25.0 in). Like all gibbons it is tailless.
With its long arms they swing on branches, brachiating at a fast pace. Like all gibbons, it lives in serially monogamous pairs in a strictly enforced territory, which is defended with vigorous visual displays and songs. The diet of the agile gibbon is generally frugivorous but have also been observed eating leaves, flowers, and insects.
Females give birth to a single offspring after seven months' gestation. The young gibbon is weaned at barely 2 years of age. When fully mature, at about 8 years, it leaves its family group in order to look for a mate.
Distribution and habitat
The agile gibbon is found on Sumatra southeast of Lake Toba and the Singkil River, in a small area on the Malay Peninsula, and south Thailand near the Malaysian border. It predominantly lives arboreally in rain forests and rarely comes to the ground.
- Groves, C. P. (2005). Wilson, D. E.; Reeder, D. M. eds. Mammal Species of the World (3rd ed.). Baltimore: Johns Hopkins University Press. pp. 179. OCLC 62265494. ISBN 0-801-88221-4. http://www.bucknell.edu/msw3/browse.asp?id=12100758.
- Geissmann, T. & Nijman, V. (2008). Hylobates agilis. In: IUCN 2008. IUCN Red List of Threatened Species. Retrieved 4 January 2009.
- Kuester, J. (2000). "Hylobates agilis". Animal Diversity Web. http://animaldiversity.ummz.umich.edu/site/accounts/information/Hylobates_agilis.html. Retrieved 6 January 2012.
- "Fact sheet: agile gibbon" (pdf). EAZA Ape Campaign. 2010. http://www.apecampaign.org/wp-content/uploads/2010/06/gibbon-agilis-fact-sheet.pdf. Retrieved 6 January 2012.