The Wild Bornean Orang Utans

Male Orang Utan (around 20 years old) in Danum Valley

The Bornean Orang Utan (Pongo pygmaeus) is a species of Orang Utan native to the island of Borneo.  Together with  the slightly smaller Sumatran Orang Utan, it belongs to the only genus of great apes native to Asia.

It is a big challenge to photograph Orang Utans in the wild, they are quite shy, and it is not often that you can get close enough to get a decent clear uncluttered view.  During my last 10-day trip to Sabah earlier this year I was privileged to encounter a total of 11 individuals including two females with juveniles, however, only in 2 cases did circumstances permit me to take decent images.

The Bornean Orang Utan lives in tropical and subtropical moist broadleaf forests in the Bornean lowlands as well as well in mountainous areas up to 1500 m elevation.  It needs to cover large distances to find trees bearing fruits.

About 60% of the Orang Utan’s diet includes fruit (durians, jackfruit, lychees, Laran, mangosteens, and figs), while the rest comprises young leaves, insects, tree bark, and occasionally eggs and small vertebrates.  They obtain water not only from fruit, but also from tree holes.  Orang Utans have been seen using spears to catch fish.

The Bornean Orang Utan travels on the ground more than its Sumatran counterpart, this may due to the fact that there is no need to avoid the large predators like Tigers, only existing in Sumatra.

They are generally solitary, and males and females normally come together only to mate.  Newborn Orang Utans nurse every 3 to 4 hours, and begin to take soft food from their mothers’ lips by four months.  During the first year of its life, the baby clings to its mother’s abdomen and gripping her fur. After weaning at about 3.5 years, young individuals become gradually independent of their mother after she gives birth to a 2nd young.  Babies often stay with their mothers until they are 8 to 9 years old!

Mother with juvenile in Laran tree @ Kinabatangan River

The long period taken to reach sexual maturity, the long inter-birth periods, and the fact that Orang Utans normally give birth to just a single young, mean that they have an extremely slow reproductive rate.  This makes the Orang Utan population highly vulnerable to excessive mortality, and means that populations take a long time to recover from population declines.

Today the species continues to be threatened by habitat degradation as a result of legal and illegal logging, forest fires, and conversion to agriculture – in particular oil palm plantations.  More than 80% of  Orang Utan habitat has been changed or destroyed by these factors over the past 40 years.

Orang Utan distribution on Borneo (Indonesia & Malaysia).  As can be seen the distribution of Orang Utan is repidly decreasing, as humans reduce the available habitat for the apes.  Copyright Hugo Ahlenius, UNEP/GRID-Arendal

Individuals having lost their natural habitat sometimes enter oil palm estates, where they are often shot as pests, with mother and babies being particularly vulnerable.  Mothers are often killed and the infants sold into the illegal pet trade.  The species are also hunted for meat in some areas. Many of the remaining populations are very fragmented putting them at considerable risk.

According to the IUCN, it is expected that in 10-30 years Orang Utans will be extinct if there is no serious effort to overcome the threats they are facing.  This view is also supported by the United Nations Environment Programme.

Male battle-scarred Orang Utan with Cheek pads, around 26 years old, eating Laran fruits.

Over the years I have been particularly impressed with the conservation efforts of WWF, however, NGO’s like Malaysia Nature Society has also been successful in putting pressure on authorities in Indonesia and Malaysia to give forest preservation and restoration a much higher priority.  Let us continue to give these NGO’s our full support.  Below are some useful websites, please support them!


4 replies
  1. -
    - says:

    The Orang Utan babies are around 2.5 years old, and are a bit on the slim side, however, during my visit there was enough fruiting trees, but this is of course very seasonal!


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