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.

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

Shibai Xiao / Hainan black-crested gibbon (Nomascus hainanus) young male in tree, Bawangling National Nature Reserve, Hainan Island, China.

Heather Angel / Chinese white cheeked gibbon (Nomascus leucogenys) female hanging, carrying baby aged two weeks. Parents released into wild from captive breeding programme. Wild Elephant Valley / Xishuangbanna, Yunna...

Heather Angel / Chinese white cheeked gibbon (Nomascus leucogenys) female walking whilst carrying baby aged two weeks, holding on to vines for support. Parents released into wild from captive breeding programme. Wild...

Heather Angel / Northern white cheeked gibbon (Nomascus leucogenys) female hanging from tree with baby aged two weeks. Wild Elephant Valley / Xishuangbanna, Yunnan Province, China.

Suzi Eszterhas / Buff-cheeked gibbon (Nomascus gabriellae). Native to Asia. Captive.

Suzi Eszterhas / Buff-cheeked gibbon (Nomascus gabriellae) looking out from behind tree trunk. Native to Asia. Captive.

Ernie Janes / Yellow-cheeked gibbon (Nomascus gabriellae) female, close up of foot against glass. Captive, occurs in Vietnam, Laos, and Cambodia

Magnus Lundgren / Wild Wonders of China / Central Yunnan black crested gibbon (Nomascus concolor jingdongensis) moving through trees, silhouetted. Wuliangshan Nature Reserve, Jingdong, Yunnan Province, China.

Magnus Lundgren / Wild Wonders of China / Central Yunnan black crested gibbon (Nomascus concolor jingdongensis), dominant male vocalising. Wuliangshan Nature Reserve, Jingdong, Yunnan Province, China.