Gibbon

For other uses, see Gibbon (disambiguation).

Gibbons are small apes that are grouped in the family Hylobatidae. The family is divided into four genera based on their diploid chromosome number: Hylobates (44), Bunopithecus (38), Nomascus (52), and Symphalangus (50). One unique aspect of gibbon physiology is that the wrist is comprised of a ball and socket joint, allowing for biaxial movement. Such a joint greatly reduces the amount of energy needed in the upper arm and torso, while also reducing stress on the shoulder joint itself.

Also called the lesser apes, gibbons differ from great apes (chimpanzees, gorillas, orangutans and humans) in being smaller, pair-bonded, in not making nests, and in certain anatomical details in which they superficially more closely resemble monkeys than the great apes do. They occur in tropical and subtropical rainforests from northeast India to Indonesia and north to southern China. Gibbons are masters of their primary mode of locomotion, brachiation, allowing them to swing from branch to branch distances of up to 50 feet, at speeds as much as 35 mph. Strongly territorial, they defend their boundaries with vigorous visual and vocal displays. The vocal element, which can often be heard for long distances, consists of a duet between the mated pair, the young animals sometimes joining in. This eerie song can make them an easy find for poachers who engage in the illegal wildlife trade and sales of body parts for use in traditional medicine. Most species are threatened or endangered, and the most important reason is degradation or loss of their forest habitat.

The species include the Siamang, the White-handed or Lar Gibbon, and the Hoolock Gibbon. The Siamang, which is the largest of the 14 species, is distinguished by having two fingers on each hand stuck together, hence the generic and species names Symphalangus and syndactylus.

Classification

• Family Hylobatidae: gibbons
  • Genus Hylobates
    • Lar Gibbon or White-handed Gibbon, Hylobates lar
    • Agile Gibbon or Black-handed Gibbon, Hylobates agilis
    • Bornean White-bearded Gibbon, Hylobates albibarbis
    • Müller's Bornean Gibbon, Hylobates muelleri
    • Silvery Gibbon, Hylobates moloch
    • Pileated Gibbon, Hylobates pileatus
    • Kloss Gibbon or Bilou, Hylobates klossii
  • Genus Bunopithecus
    • Hoolock Gibbon, Bunopithecus hoolock
  • Genus Symphalangus
    • Siamang, Symphalangus syndactylus
  • Genus Nomascus
    • Concolor or Black Crested Gibbon, Nomascus concolor
      • Nomascus concolor concolor
      • Nomascus concolor nasutus
      • Nomascus concolor lu
      • Nomascus concolor jingdongensis
      • Nomascus concolor furvogaster
    • Hainan Gibbon, Nomascus hainanus
    • Northern White-cheeked Gibbon, Nomascus leucogenys
    • Southern White-cheeked Gibbon, Nomascus siki
    • Red-cheeked Gibbon, Nomascus gabriellae

External links

• Gibbon Conservation Center