Reintroduction of Orangutans: A New Approach. A Study on the Behaviour and Ecology of Reintroduced Orangutans in the Sungai Wain Nature Reserve, East Kalimantan Indonesia

The reintroduction of ex-captive orangutans Pongo pygmaeus) is part of a comprehensive conservation program to preserve this species and it’s habitat. During the last decades the orangutan has been under severe threat throughout it’s range- Northern Sumatra, Kalimantan and East Malaysia- due to massive habitat destruction, hunting pressure and the illegal pet trade. The predecessor of orangutan reintroduction was ‘rehabilitation’ of the ex-captive apes. Rehabilitation has been described as “the training of behaviourally inadequate animals in skills which allow them to survive with greater independence” (Hannah and McGrew 1985). The first attempt to rehabilitate ex-captive orangutans came from Mrs. Barbara Harrisson in the 1960s in Sarawak (Harrisson 1962) when it was first realized that the orangutan was threatened with extinction. In 1964 a rehabilitation centre for orangutans-Sepilok- was set up in Sabah by the Wildlife Department (de Silva 1971). In 1971 a rehabilitation centre was established in addition to a research project on the wild orangutan population in the Ketambe area in the Gunung Leuser National Park, Northern Sumatra (Rijksen 1974, 1978). That same year a rehabilitation centre was initiated for Bornean orangutans in the Tanjung Puting Reserve in Central Kalimantan together with a long term study on the wild population (Galdikas-Brindamour 1975). In 1973 the Frankfurt Zoological Society sponsored another rehabilitation project also in the Gunung Leuser National Park (Aveling 1982; Borner 1979). Then in 1977 the Semenggok centre (originally for gibbons) was opened in Sarawak (Aveling and Mitchell 1982).