Taxonomic Classification:
Family: Hylobatidae
Genera: Hylobates, Hoolock, Nomascus, Symphalangus
Species: Hylobates lar, H. agilis, H. muerlleri, H. moloch, H. pileatus, H. klossii, Hoolock hoolock, H. leuconedys, Symphalangus syndactylus, Nomascus concolor, N. nasutus, N. leucogenys, N. siki, N. gabriellae
Common Name: Gibbon
Physical Description:
Gibbons have low sexual dimorphism, and range in size from 16.5 to 35.0 inches and weigh between 9.7 and 32.6 pounds. They are small, long-armed, brachiating, bipedal, and tailless apes with gracile bodies, an upright posture, and long hands and feet. They are the most diverse of the living apes, and are known for their wrists, which are composed of a ball and socket joint for biaxial movement. Their fur color ranges greatly, but it is usually brown, gray, or black with markings on the head and face. Gibbons
generally have a brain size of about 100 cc and their dentition is as follows: 2:1:2:3.
Gibbons are omnivores and spend about 32.6% of their time gathering food from sources around their territories. They rely mostly on figs and other fruit as their main source of nutrition. They also consume other plant parts such as leaves (depending on the available sources), flowers, and sprouts. For protein they eat eggs or small invertebrates and rarely invertebrates such small birds or mammals.
The percentage makeup of their diet is the following and differs slightly from species to species:
57-79% – Fruit and Flowers (25% of this is figs)
4-17% – Leaves
10% – Invertebrate Animal Matter

Geographic Location:
Gibbons are found in Southeast Asia. They have four genera and ten to twelve species which are located from the Brahmaputra to Southern China to Sumatra to Borneo and Java.
Social Organization: The average group size for Gibbons is about 6. The groups consist of a monogamously mated pair, and roughly 4 offspring. The adult female is the dominant as opposed to the male. In fact, the hierarchy for a group is this: Female, male offspring, then the adult male.
Gibbons are known for their song. Their song is used to announce location, defend territory, and maintain bonds.
Gibbons are monogamous. They form carefully chosen pair bonds which they keep for life. If one member dies, the other will not find a new partner. Each pair bond (and the resulting offspring) lives in their own territory. The characteristic songs they sing are used to bond within the pair and communicate between groups.
Female estrus swellings occur during ovulation about every 27.3 days
Infants are born signally after a gestation period of 210-235 days and reach sexual maturity at age six or seven. At this point they break off from their family group and find a mate of their own. Depending on the available food sources, infants are born up to once every two to three years.

Parental  Care:
Gibbons are physically independent at about three, mature at about six, and usually leave the family group at about eight, though they may spend up to ten years in their family group.
Language/communication skills:
Gibbons communicate mainly through song. Mated pairs will sing duets together every morning as part of their routine. They also have special warning songs telling other gibbons to stay out of their territory and songs to warn others of predators. Their songs can carry for miles, and they vary by group, but warning songs are understood by all.

Evidence of Culture:
Young gibbons learn to swing between branches by watching their parents and other older gibbons, and learn to sing in their group’s particular style by listening to the parent of the same sex. Gibbons’ songs vary by group, and offspring will sing with some qualities of both parents. Mothers are very affectionate and protective of her young and her mate.

“Gibbons.” Grzimek’s Encyclopedia: Mammals. Vol. 2. McGraw-Hill , 1990. Print.
Gron KJ. 2009 April 6. Primate Factsheets: Lar gibbon (Hylobates lar) Taxonomy, Morphology, & Ecology . <;. Accessed 2010 September 26.
Grzimek’s Animal Life Encyclopeda, 2nd dition. Volume 14, Mammals III, edited by Michael Hutchins, Devra G. Kleiman, Valerius Geist, and Melissa C. McDade. Farmington Hills, MI: Gale Group 2003.
Hodgkiss, S., Thetford, E., Waitt, C. and Nijman, V. (2010), Female reproductive parameters in the Javan gibbon (Hylobates moloch). Zoo Biology, 29: 449–456. doi: 10.1002/zoo.20277

Photographer unknown
Second Photograph property of BBC

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One Response to Gibbons

  1. Megan M. says:

    Oh man, that’s a great pic. Nice work.

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