The wild orangutan, humankind's third-closest living relative, could become extinct in the next 20 years. Habitat destruction is threatening their existence, says Birut Galdikas, a biological anthropologist and conservationist from Simon Fraser University in Burnaby, British Columbia, Canada. Orangutans now can only be found in the forests of Sumatra and Borneo in Indonesia. Using satellite imaging and aerial photographs, researcher Carel van Schaik of Duke University, Sumatra, Indonesia, and his colleagues, estimated that the population dropped from 12,000 in 1993 to 6,500 in 1999. In a bid to save them, researchers and zookeepers have launched the Orangutan Network, under the leadership of van Schaik ( Science , Vol 288, No 5469).