除此之外，報告中亦顯示，小如鼠狐猴，大至山地大猩猩之間的物種，其生存皆倍受威脅。非洲大陸上13種紅疣猴中，已有11種經評估後被列名於嚴重瀕絕或瀕絕名單。其中Procolobus pennantiibouvieri與Procolobus badius waldroni兩物種可能已經絕種，前者已有25年不曾為人類所目睹；而靈長類學家上一次發現後者的時間則早在1978年之遙。
Monkeys, apes and other primates are vanishing from the face of the Earth, with some "literally being eaten to extinction," according to the world's foremost primate authorities gathered this week at the 22nd International Primatological Society Congress in Edinburgh.
Habitat destruction, through the burning and clearing of tropical forests, which also emits at least 20 percent of global greenhouse gases, is a major threat to primates. Other threats include the hunting of primates for food and the illegal wildlife trade.
The first comprehensive review in five years of primate conservation status presented at the conference shows that of the 634 kinds of primates in the world, almost half are in danger of going extinct, according to the criteria of the Red List of Threatened Species compiled by the IUCN.
All great apes - all gorillas, all chimpanzees, all orangutans, all bonobos - are either Endangered or Critically Endangered. In both Vietnam and Cambodia, 90 percent of primate species are considered at risk of extinction. Populations of gibbons, leaf monkeys, langurs and other species have dwindled due to habitat loss worsened by hunting for food and to supply the wildlife trade in traditional Chinese medicine and pets.
Elsewhere, the survival of species from tiny mouse lemurs to massive mountain gorillas is in jeopardy, the report shows. In Africa, 11 of the 13 kinds of red colobus monkeys assessed were listed as Critically Endangered or Endangered. Two may already be extinct: Bouvier's red colobus, Procolobus pennantiibouvieri, 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.
Non-human primates are important to the health of their surrounding ecosystems, the report points out.
Through the dispersal of seeds and other interactions with their environments, primates help support plant and animal life in tropical forests. Healthy forests provide vital resources for local human populations, and also absorb and store carbon dioxide that causes climate change.
Despite the grim assessment, conservationists point to one success in helping targeted species recover. In 2003, two Brazilian primates - the black lion tamarin and the golden lion tamarin which were downlisted to Endangered from Critically Endangered are now well-protected but remain small, and conservationists say there is an urgent need for reforestation to provide new habitat for their long-term survival.
Scientists also considered reclassifying the mountain gorilla to Endangered from Critically Endangered due to increasing populations in their only habitat - the protected mountain jungles of Rwanda, Uganda and Democratic Republic of Congo. But the slayings of eight mountain gorillas in 2007 and continuing political turmoil in the region delayed the planned reclassification.
In total, the gorillas, bonobo and chimpanzees occur in 21 African nations. Of the orangutans, one species is wedged into northernmost Sumatra, and the other, divided into three subspecies, survives on the island of Borneo.