LONDON , England ( CNN ) -- Almost 50 percent of the world 's primates are in danger of extinction , according to a report from an international conservation group that cites habitat destruction and hunting as the two greatest threats . The golden-headed lion tamarin has been brought back from the edge of extinction . The situation is especially dire in Asia , where the report says more than 70 percent of monkeys , apes , and other primates are classified as vulnerable , endangered , or critically endangered . `` We 've raised concerns for years about primates being in peril , but now we have solid data to show the situation is far more severe than we imagined , '' said Russell Mittermeier , president of Conservation International and chairman of the IUCN Primate Specialist Group . `` Tropical forest destruction has always been the main cause , but now it appears that hunting is just as serious a threat in some areas , even where the habitat is still quite intact , '' he said . The report from Conservation International , issued at this week 's International Primatological Society Congress in Edinburgh , Scotland , looked at the world 's 634 kinds of primates , mankind 's closest relatives . Conservation International funded the review along with the Margot Marsh Biodiversity Foundation , Disney 's Animal Kingdom , and the Swiss-based IUCN , or International Union for Conservation of Nature . The report found that about 90 percent of primate species in Vietnam and Cambodia were at risk of extinction . Populations of gibbons , leaf monkeys , langurs and other species had dwindled , the report said , because of `` rampant habitat loss exacerbated by hunting for food and to supply the wildlife trade in traditional Chinese medicine and pets . '' Jean-Christophe Vie , deputy head of the IUCN Species Program , called the situation in southeast Asia terrifying . `` To have a group of animals under such a high level of threat is , quite frankly , unlike anything we have recorded among any other group of species to date , '' he said in a news release . Great apes like gorillas and bonobos still faced challenges in Africa , the report said , but it was the smaller primates -- such as the red colobus monkey , with its striking white , black and rust-colored coat -- that could die out first . In Africa , 11 of the 13 kinds of red colobus monkeys assessed in the report were listed as critically endangered or endangered , and two may already be extinct , the report said . Bouvier 's red colobus has not been seen in 25 years , and despite occasional sightings , no primatologist has recorded a living Miss Waldron 's red colobus since 1978 , the report says . Primates are important to the health of their surrounding ecosystems , the report 's authors say , supporting a wide range of plant and animal life in the world 's tropical forests . Healthy forests , in turn , provide vital resources for local human populations . Reforestation is crucial to restoring primate populations because it restores their habitat , the report said . It cites the cases of the black lion tamarin and golden lion tamarin in Brazil , which were downgraded from critically endangered to endangered after three decades of conservation efforts . `` If you have forests , you can save primates , '' said Anthony Rylands , a scientist with Conservation International and the deputy chair of the IUCN Primate Specialist Group . `` The work with lion tamarins shows that conserving forest fragments and reforesting to create corridors that connect them is not only vital for primates , but offers the multiple benefits of maintaining healthy ecosystems and water supplies while reducing greenhouse gas emissions that cause climate change . ''
Report : Almost 50 percent of world 's primates in danger of extinction . Situation is especially dire in Asia , where 70 percent of primates threatened . 90 percent of primate species in Vietnam and Cambodia at risk of extinction .