Ingo Arndt / White-handed gibbon {Hylobates lar} feeding in {Ficus sp} tree Khao Yai NP Thailand

Ingo Arndt / White-handed gibbon portrait {Hylobates lar} Thailand

Ingo Arndt / White-handed gibbon portrait {Hylobates lar} Khao Yai NP, Thailand

Roland Seitre / Pileated gibbon (Hylobates pileatus) female climbing through trees, Angkor Centre for Conservation of Biodiversity, Siem Reap, Cambodia. Endangered species.

Thomas Marent / Buff-cheeked Gibbon (Nomascus gabriellae) female, Phnom Tamao Wildlife Rescue Center, Cambodia

Roland Seitre / Muller's Bornean Gibbon (Hylobates muelleri) in tree, native to Borneo

Roland Seitre / Muller's Bornean Gibbon (Hylobates muelleri) in tree, native to Borneo

Roland Seitre / White-handed Gibbon (Hylobates lar) calling while hanging from branch, native to Asia

Roland Seitre / Dwarf Gibbon (Hylobates klossii) sub-adult in tree, native to Asia

Rod Williams / Northern / Chinese white-cheeked gibbon (Nomascus leucogenys) female head portrait, Laos, Vietnam, critically endangered species. Captive.

Bernard Castelein / Hoolock Gibbon (Hylobates hoolock) male hanging from a branch. Assam, India, February.

Thomas Marent / Bornean White-bearded Gibbon (Hylobates albibarbis) walking on liana, Tanjung Puting National Park, Borneo, Indonesia