Hundreds of species of primates, man's closest living relatives, are being pushed to the brink of extinction by human activity. A press release by Conservation International reports that 'deforestation, commercial bushmeat hunting, and the illegal animal trade' have brought one in four primate species within risk of exinction.

A report put together at the 20th Congress of the International Primatological Society, Primates in Peril: The World's 25 Most Endangered Primates, lists the following 25 primates as most threatened and in need of protection:

Madagascar
1. Greater bamboo lemur (Prolemur simus)
2. White-collared lemur (Eulemur albocollaris)
3. Silky sifaka (Propithecus candidus)
4. Perrier’s sifaka (Propithecus perrieri)

Africa
5. Mt. Rungwe galago (Galagoides sp.)
6. Bioko red colobus (Procolobus pennantii pennantii)
7. Tana River red colobus (Procolobus rufomitratus)
8. White-naped mangabey (Cercocebus atys lunulatus)
9. Sanje mangabey (Cercocebus sanjei)
10. Eastern gorilla (Gorilla beringei)
11. Cross River gorilla (Gorilla gorilla diehli)

Asia
12. Horton Plains slender loris, Ceylon Mountain slender loris (Loris lydekkerianus nycticeboides)
13. Pig-tailed langur, Pagai pig-tailed snub-nosed monkey, Siberut pig-tailed snub-nosed monkey (Simias concolor)
14. Miller’s grizzled surili (Presbytis hosei canicrus)
15. Delacour’s langur, white-rumped black leaf monkey (Trachypithecus delacouri)
16. Golden-headed langur, Tonkin hooded black langur (Trachypithecus poliocephalus poliocephalus)
17. Western purple-faced langur (Semnopithecus vetulus nestor)
18. Grey-shanked douc (Pygathrix nemaeus cinerea)
19. Tonkin snub-nosed monkey (Rhinopithecus avunculus)
20. Hainan black-crested gibbon (Nomascus nasutus hainanus)
21. Sumatran orangutan (Pongo abelii)

Neotropics
22. Black-faced lion tamarin (Leontopithecus caissara)
23. Buffy-headed tufted capuchin (Cebus xanthosternos)
24. Brown spider monkey (Ateles hybridus brunneus)
25. Northern muriqui (Brachyteles hypoxanthus)

Find out more:

• Primates on the Brink (Conservation International)
• Quarter of Primates Face Abyss (BBC News)
• Primates in Peril (PDF) (Conservation International)
• Primates in Peril Snapshots (Conservation International)

Photo © Ferenc Cegledi / Shutterstock.