Heather Angel / Northern white cheeked gibbon (Nomascus leucogenys) female standing in tree with baby aged two weeks. Parents captive bred and released. Wild Elephant Valley / Xishuangbanna, Yunnan Province, China, 2...

Magnus Lundgren / Wild Wonders of China / Central Yunnan black crested gibbon (Nomascus concolor jingdongensis), mother and baby hanging in canopy. Wuliangshan Nature Reserve, Jingdong, Yunnan Province, China.

Sandesh Kadur / Western hoolock gibbon (Hoolock hoolock) male hanging from branch, Assam, India.

Tim Laman / Skywalker hoolock gibbon (Hoolock tianxing) formerly described as Eastern hoolock gibbon (Hoolock leuconedys) Gaoligong Mountains National Nature Reserve, Yunnan Province, China.

Tim Laman / Skywalker hoolock gibbon (Hoolock tianxing) formerly described as Eastern hoolock gibbon (Hoolock leuconedys) Gaoligong Mountains National Nature Reserve, Yunnan Province, China.

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 / Young male Northern White-cheeked Crested Gibbon (Nomascus leucogenys) Northern Vietnam. Critically Endangered, Captive