for National Geographic News
Two new populations of rare primate species, both numbering in the thousands, have been discovered in a Cambodia preserve.
A 2008 survey estimates 42,000 black-shanked doucs and 2,500 yellow-cheeked crested gibbons live in Cambodia's Seima Biodiversity Conservation Area.
"These Cambodian animals represent undoubtedly the largest [known] remaining global populations of either species," said lead report author Tom Clements, a researcher at the nonprofit Wildlife Conservation Society (WCS), which led the survey.
Before this survey, the largest known populations of either species were 600 black-shanked doucs and 200 yellow-cheeked crested gibbons in neighboring Vietnam—the only other country where the two species are found. (See a photo of another rare primate group found recently in Vietnam.)
The primates are listed as endangered on the International Union for Conservation of Nature (IUCN)'s Red List of Threatened Species.
They are among the more than 70 percent of Asia's primate species in sharp decline.
Sporting long white whiskers, the black-shanked douc lives high in the trees and feasts on leaves and fruit.
Yellow-cheeked crested gibbons are also tree dwellers, eating and sleeping in the upper canopy of evergreen forests.
Between 2005 and 2008, Clements and his team conducted annual surveys in a 300-square-mile (789-square-kilometer) area of Cambodia.
The surveys are the first known attempts to obtain accurate population estimates for the region's native wildlife.
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