Meet the world's endangered primates-photos

Nearly half of all primates are in danger of becoming extinct, according to a study by the International Union for the Conservation of Nature. Habitat destruction and hunting for food and the illegal wildlife trade are the main threats to the world's 634 primate species – 303 of which are now classed as vulnerable, endangered and critically endangered. Here are some of the species under threat
 
The grey-shanked douc langur (Pygathrix cinerea) is found in Vietnam. In Asia, more than 70% of primates are classified on the IUCN 'red list' as vulnerable, endangered or critically endangered; in both Vietnam and Cambodia, approximately 90% of primate species are considered at risk of extinction

The yellow-cheeked crested gibbon (Nomascus gabriellae) was upgraded from vulnerable to endangered. In south-east Asia, populations of gibbons, leaf monkeys and langurs have dropped due to rapid habitat loss and hunting to satisfy the Chinese medicine and pet trade

The Qinling golden snub-nosed monkey (Rhinopithecus roxellana qinlingensis), found in China, has been reclassified from vulnerable to endangered. Habitat destruction, through the burning and clearing of tropical forests, is a major threat to primates. Other threats include the hunting of primates for food and an illegal wildlife trade Photograph: Russell A Mittermeier/Conservation Internationall
 
Kirk's red colobus (Procolobus kirkii) is one of the 13 species of red colobus monkey assessed in Africa, of which 11 were listed as endangered or critically endangered. Two may already be extinct: Bouvier’s red colobus (Procolobus pennantii bouvieri) has not been seen in 25 years, and no living Miss Waldron’s red colobus (Procolobus badius waldroni) has been seen by a primatologist since 1978, despite occasional reports that some still survive
 
 There was some good news for primates: conservation efforts in Brazil have helped targeted species, such as this golden lion tamarin (Leontopithecus rosalia), to recover, and their status has been upgraded from critically endangered to endangered
 
The fortunes of the Javan gibbon (Hylobates moloch), found in Indonesia, have improved, and it has been moved from critically endangered to endangered
 
An adolescent mountain gorilla (Gorilla gorilla beringei) looks skyward. The scientists came close to downlisting the mountain gorilla to endangered following population increases in their forest habitat, which spans the borders of Rwanda, Uganda and the Democratic Republic of Congo. However, political turmoil in the region and an incident in which eight animals were killed in 2007 led them to delay the planned reclassification
 

The male Sclater's black lemur (Eulemur flavifrons) is also known as the blue-eyed back lemur Photograph: Nora Schwitzer/Bristol Conservation and Science Foundation

 

A greater bamboo lemur (Prolemur simus) in Madagascar Photograph: Haroldo Castro/Conservation International

 
This female hoolock gibbon at the Wildlife Rescue Centre near Kaziranga, India, still has her juvenile pelage, or fur Photograph: Russell A Mittermeier/Conservation Internatiol

 
The yellow-tailed woolly monkey (Oreonax flavicauda) of Peru Photograph: Conservation International

 

A young silky sifaka lemur (Propithecus candidus), which live in Madagascar and the islands of the Indian Ocean Photograph: Russell A Mittermeier/Conservation International 

 

This northern sportive lemur (Lepilemur septentrionalis) was spotted in Tsaratanana-be forest, a few kilometres north-west of Ankavonagana in Madagascar Photograph: Russell A Mittermeier/Conservation International

 

A pig-tailed langur or simakobu (Simias concolor) hangs out in the Peleonan forest of the Indian Ocean island of Siberut Photograph: Russell A Mittermeier/Conservation International

 

A quartet of saddleback tamarins Photograph: Haroldo Castro/Conservation International