Sepilok, a reserve of 43 square kilometres of lowland primary rainforest and mangrove, was set up in 1964 to protect the orang-utan from extinction. It is the first and largest of only four orang-utan sanctuaries in the world and now has 40,000 visitors a year. Logging has seriously threatened Sabah’s population of wild orang-utan, as has their capture for zoos and as pets. The orang-utan lives on the islands of Borneo and Sumatra and there are estimated to be as few as 10,000 still in the wild. In Sabah there are populations of orang-utan in the Kinabatangan basin region, Danum Valley Conservation Area and a few other isolated tracts of jungle.
Sepilok is an old forest reserve that was gazetted as a forestry experimentation centre as long ago as 1931 and by 1957 logging had been phased out. Orphaned or captured orang-utans that have become too dependent on humans through captivity are rehabilitated and protected under the Fauna Conservation Ordinance and eventually returned to their natural home. Many, for example, may have been captured by the oil-palm planters because they eat the young oil palm trees.