There are just over 40,000 orangutans left on the island of Borneo. But history has shown that population could decline rapidly if forest habitats continue to be destroyed at the current rate. Poaching also continues to be a threat to Borneon orangutan populations. WWF is actively involved in global efforts to protect habitat and halt the illegal trade in orangutans.
Common namesBornean orangutan; Orangoutan de Borneo(Fr); Orangután de Borneo(Sp)
HabitatTropical and Subtropical Moist Broadleaf Forests
PopulationCentral Bornean = 38,000; NW Bornean = 3,000
StatusEndangered (EN - A2cd; IUCN) CITES: Appendix I
Little resilience in the face of logging and fireThe Bornean orangutan is now recognised as a different species from its Sumatra relative. Three subspecies are recognized: Pongo pygmaeus pygmaeus, P.p. morio, and P. p. wurmbii, the most common Bornean subspecies. Although extensive, the latter's habitat is increasingly fragmented in the remaining swamp and lowland dipterocarp forests of Central and West Kalimantan.
It is estimated that about one third of Borneo's orangutan populations were lost during the 1997/ 98 forest fires. On the Indonesian side of Borneo, populations of this subspecies are not faring well either.
Although some populations live inside protected areas, illegal logging still takes place within these areas and hence remains a major threat to the survival of this species.
Tropical and Subtropical Moist Broadleaf Forests
Borneo Lowland and Montane Forests
Adult orangutans are generally solitary, although temporary aggregations are occasionally formed. The large home ranges of males overlap the ranges of several adult females. Adult males are generally hostile to one another, although they do not display territoriality.
After weaning at about 3.5 years of age, young individuals become gradually independent of their mother after she gives birth to a second young. The age of first reproduction in the Borneo orangutan is around 10-15 years of age, but there may be differences between the various sub-species.
Orangutans usually give birth to a single young, or occasionally twins, probably not more than once every five years. For the Bornean orangutan, the inter-birth interval can be as low as 5 years in high quality habitats.
About 60% of the orangutan's diet includes fruit (e.g. durians, jackfruit, lychees, mangosteens, mangoes and figs), while the rest comprises young leaves and shoots, insects, soil, tree bark, woody lianas, and occasionally eggs and small vertebrates. They obtain water not only from fruit, but also from tree holes.
Previous population and distribution
A ten-year ongoing census of orangutans in the Sebangau Ecosystem recorded a 50% decline in numbers, from 12,000 individuals in 1995 to 6,000 in 2004. In Kutai National Park, perhaps only 10% of the area is still forested, and the orangutan population there was reduced from an estimated 4,000 in 1970 to 500 today.
The Bornean orangutan is found in Kalimantan, and Sarawak and Sabah (Malaysia); most individuals occur in Kalimantan, where extensive areas of forest still exist, especially along the east coast.
Orangutan distribution on Borneo (Indonesia, Malaysia). The distribution of Orangutan on Borneo is rapidly decreasing, as humans reduce the available habitat for the apes. The loss of forest, through logging, clearing and burning, means reduced opportunities for hiding and food collection. In addition, orangutans are hunted for food and to be held in captivity.
Inspired by Krista Oragutan