The orangutan - the only great ape found in Asia - may vanish from the wild within a decade, unless illegal logging of its habitat and poaching can be greatly reduced, according to research funded by the Bronx Zoo-based Wildlife Conservation Society (WCS).
The study documents the decline in orangutans throughout their range. Northern Sumatra, Indonesia, which supported 12,000 orangutans in 1993 - the largest population in the world - lost nearly half its animals over a seven year period.
"The alarming decline in...orangutan numbers implies that the world's largest natural orangutan population will be extinct in a decade or so, unless the current trend is stopped," says the study's lead author, Dr. Carel van Schaik, a WCS research associate from Duke University who has studied wild orangutans for more than 20 years.
Ironically, area where this dramatic decline has occurred includes Sumatra's largest protected area, Leuser National Park, where rampant logging is backed by the Indonesian military and police. "All remaining forests that are accessible by road or river are subject to a seemingly unstoppable pandemic of illegal logging, regardless of their protection status," van Schaik says.
Van Schaik found that orangutan densities decreased more than 60 percent in areas that have been selectively logged, due mostly to a decline in trees that produce fruit - a critical food source for orangutans - as well as the loss of canopy trees they use for travel.
The situation in Borneo, the only other island where orangutans are found, is no better. Up to one third of Borneo's orangutans died during the wave of forest fires that swept through the area in 1997 and 1998. And a similar rash of illegal logging continues to affect the region - all fueled by the state of political instability throughout Indonesia.
To alleviate this desperate situation, WCS is calling for a moratorium on logging in old-growth forests until the political situation has stabilized, as well as renewed commitment to national parks. Conservation groups have pledged their support of government initiatives to improve protection, and work with local communities and governments to stop illegal logging.
Leuser orangutans differ from their Bornean counterparts in having higher densities, and a tendency toward more social behavior. Van Schaik has documented routine use of at least two kinds of feeding tools to extract honey from tree holes and seeds from a woody fruit protected by stinging hairs. The geographical distribution of this tool use implies that it is handed down from generation to generations.