Bernard Castelein / Coquerel's sifaka (Propithecus coquereli) in tree, relaxing, Ankarafantsika National Park, Madagascar

Bernard Castelein / Silky sifaka (Propithecus candidus) in tree, Marojejy National Park, Madagascar. Critically endagered species.

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...

Lucas Bustamante / Toque Macaques (Macaca sinica) Polonnaruwa, Central Province, Sri Lanka

Cyril Ruoso / Ringed-tailed lemur (Lemur catta) amongst granite rocks in cave. Lemurs lick minerals from the rocks. Anja Community Reserve, Madagascar.

John Shaw / Snow monkey or Japanese macaque (Macaca fuscata) female with baby clinging to her back. Jigokudani, Japan, February.

Bernard Castelein / Rhesus macaque (Macaca mulatta), mixed group of female and juveniles, walking along a track, Keoladeo National Park, Bharatpur, India

Bernard Castelein / Rhesus macaque (Macaca mulatta), juveniles playing in tree, Keoladeo NP, Bharatpur, India

Bernard Castelein / Guianan brown capuchin (Sapajus apella) chewing on branch, Pampas del Yacuma Protected Area, Bolivia

Bernard Castelein / Bolivian red howler (Alouatta sara), Pampas del Yacuma Protected Area, Bolivia

Suzi Eszterhas / Bornean Orangutan (Pongo pygmaeus) next to signs which say 'Silence please. Respect the orangutans' and 'No Smoking' Tanjung Puting National Park, Borneo, Indonesia.

Suzi Eszterhas / Red-shanked douc langur (Pygathrix nemaeus) infant sucking thumb while caretaker holds it. Animal was rescued from illegal wildlife trade, Endangered Primate Rescue Center, Cuc Phuong National Park, V...

Lorraine Bennery / White-fronted brown lemur (Eulemur albifrons) in tree, Rainforests of the Atsinanana, Marojejy National Park, Madagascar. Endangered species, endemic.

Lorraine Bennery / Red-bellied lemur (Eulemur rubriventer) huddling together in tree branches. Anjozorobe Special Reserve, Madagascar. Vulnerable species, endemic.

Lorraine Bennery / White-fronted brown lemur female (Eulemur albifrons), sitting in tree, Rainforests of Atsinanana, Marojejy National Park. Madagascar, Endangered, endemic.

Matthew Maran / Delacour's langurs (Trachypithecus delacouri) resting, Van Long Nature Reserve,Ninh Binh, Vietnam. Critically endangered

Matthew Maran / Red shanked douc langur (Pygathrix nemaeus) Son Tra Nature Reserve, Vietnam

Eric Baccega / Chimpanzee female (Pan troglodytes schweinfurthii) sleeping in a nest built in a tree, Kibale National Park, Uganda, January.

Eric Baccega / Chimpanzee juvenile (Pan troglodytes schweinfurthii) in a tree. Kibale National Park, Uganda. January.

Eric Baccega / Chimpanzee male (Pan troglodytes schweinfurthii) sleeping on the forest floor with feet up, Kibale National Park, Uganda. January.

Eric Baccega / Mountain gorilla (Gorilla beringei) juvenile aged 2 years, hanging from branch, member of the Nyakagezi group, Mgahinga National Park, Uganda. January.

Andrew Walmsley / Sumatran orangutan (Pongo abelii) mother and baby Bukit Lawang, North Sumatra.

Robin Chittenden / Tufted grey langur (Semnopithecus priam priam) baby, Sri Lanka.

Ernie Janes / Celebes crested macaque (Macaca nigra) infant, captive.

Ernie Janes / Black howler (Alouatta caraya) male and female, captive, occurs in Brazil and Paraguay. With digitally added leaf pattern.

Jabruson Motion / Conservation workers carrying a sedated Sumatran orangutan (Pongo abelii) towards vehicles and a transport box, part of a relocation programme, Sei Serdang, Prima, Batang Serangan, Langkat, North Suma...

Jed Weingarten / Wild Wonders of China / Tibetan macaque (Macaca thibetana) carrying young baby, Tangjiahe Nature Reserve, Sichuan Province, China

Lorraine Bennery / White-fronted brown lemur (Eulemur albifrons) climbing tree, looking at camera. Rainforests of the Atsinanana, Marojejy National Park, Madagascar.

Lorraine Bennery / Blue-eyed lemur (Eulemur flavifrons) male looking down from branch. Sahamalaza, Madagascar.

Lorraine Bennery / Blue-eyed lemur (Eulemur flavifrons) female in tree. Sahamalaza, Madagascar.

Lorraine Bennery / Ankarana sportive lemur (Lepilemur ankaranensis) looking out from hole in tree. Analamera National Park, Madagascar.

Lorraine Bennery / Crowned lemur (Eulemur coronatus) jumping in forest canopy. Analamera National Park, Madagascar.

Lorraine Bennery / Black lemur (Eulemur macaco macaco) female sitting in tree. Lokobe Reserve, Nosy Be, Madagascar.

Mary McDonald / Adult Mountain gorilla (Gorilla beringei beringei) holding baby, Hirwa group, Volcanoes National Park, Rwanda

Claudio Contreras / Central American spider monkey (Ateles geoffroyi) juveniles hanging by tails and playing, Calakmul Biosphere Reserve, Yucatan Peninsula, Mexico, August

Patricio Robles Gil / Kashir grey langur (Semnopithecus ajax) Dachigam National Park, Jammu & Kashmir, India.

Tim Laman / Tapanuli orangutan (Pongo tapanuliensis) Togus, adult flanged male, Batang Toru Forest. Sumatran Orangutan Conservation Project, North Sumatran Province, Indonesia.

Tim Laman / Tapanuli Orangutan (Pongo tapanuliensis). Togus, adult flanged male Batang Toru Forest Sumatran Orangutan Conservation Project North Sumatran Province Indonesia

Tim Laman / Tapanuli Orangutan (Pongo tapanuliensis). Togus, adult flanged male. Batang Toru Forest, Sumatran Orangutan Conservation Project, North Sumatran Province, Indonesia.

Tim Laman / Tapanuli Orangutan (Pongo tapanuliensis) Beti, juvenile female, daughter of Beta, in the trees, Batang Toru Forest, Sumatran Orangutan Conservation Project, North Sumatran Province, Indonesia

Houdin and Palanque / Decken's sifaka (Propithecus deckenii) grooming each other, Tsimembo area, Madagascar. Lenses for Conservation project.

Houdin and Palanque / Decken's sifaka (Propithecus deckenii) female and her young playing, Tsimembo area, Madagascar. Lenses for Conservation project.

Houdin and Palanque / Decken's sifaka (Propithecus deckenii) female and her young playing, Tsimembo area, Madagascar. Lenses for Conservation project.

Houdin and Palanque / Decken's sifaka (Propithecus deckenii) Tsimembo area, Madagascar. Lenses for Conservation project.

Houdin and Palanque / Decken's sifaka (Propithecus deckenii) grooming each other, Tsimembo area, Madagascar. Lenses for Conservation project.

Houdin and Palanque / Pale fork-marked lemur (Phaner pallescens) in search for food at night, Kirindy Deciduous Forest, Madagascar. Lenses for Conservation project.

Houdin and Palanque / Madame Berthe's Mouse Lemur (Microcebus berthae), the worlds smallest primate, Kirindy forest, Madagascar. Lenses for Conservation project.

Lorraine Bennery / Sifaka de Decken (Propithecus deckenii), sitting in tree, Tsingy de Bemaraha National Park, Madagascar, Endangered, endemic.