Illiger, 1811 14 species, see text Gibbons are small apes that are traditionally grouped in the genus Hylobates. The genus is divided into four subgenera based on their diploid chromosome number: Hylobates (44), Bunopithecus (38), Nomascus (52), and Symphalangus (50). Hylobates is the only genus in the family Hylobatidae. 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 Lar Gibbon or White-handed 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 subgeneric and species names Symphalangus and syndactylus.

Classification

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

External links

• Gibbon Conservation Center