Re-introduction of the Sumatran orangutan in Sumatra, Indonesia

Summary

The Sumatran orangutan (Pongo abelii), Critically Endangered with roughly 6,600 remaining and named one of the world's 25 most endangered primates, is the subject of the only Sumatran orangutan reintroduction effort, the Sumatran Orangutan Conservation Program (SOCP), a partnership between Indonesia's forestry department, the PanEco Foundation, Frankfurt Zoological Society and Yayasan Ekosistem Lestari. Confiscated ex-pet orangutans are first treated at a medical quarantine center near Medan, North Sumatra, opened in 2002, where veterinarians screen for tuberculosis, hepatitis and parasites, implant microchips, and gradually socialize animals in group cages, often their first contact with other orangutans since their mothers were killed by poachers. After field surveys between 1996 and 2000 identified the Bukit Tigapuluh National Park buffer zone, a 350,000-hectare lowland forest tract from which orangutans had been absent since the 1800s, as suitable habitat with fruit densities matching thriving wild populations, the first orangutans were transferred there in 2002 and released beginning January 2003. Over 100 orangutans have since been released, individually or in pairs timed to fruiting season, with at least three wild conceptions and births confirmed among attentive mothers; each is tracked from night-nest to night-nest to record ranging, diet and social behavior, supported by a permanent wildlife protection patrol. Major difficulties included incomplete monitoring coverage, ongoing habitat conversion to plantations even within buffer zones, and weak prosecution of orangutan trafficking. The project rates itself Successful, citing a new wild population in habitat unoccupied for up to 150 years.