The Orang Utans of Sepilok

Dear Readers,  when I was choosing a place to visit for my sixtieth birthday it was the orang-utans of Borneo that finally made up my mind. I have spent time in the past with chimpanzees and gorillas, but have never had the opportunity to meet one of these ‘men of the forest’. So, my holiday started off with several visits to Sepilok Orang Utan Rehabilitation Centre, a 43 sq kilometre protected reserve in Sabah. This was founded in 1964 to look after orphaned orang-utans, and the need has never been greater. We shall (sadly) return to this subject over the next few days, but as you probably know, logging and palm oil production has destroyed the majority of Malaysia and Indonesia’s primary forest, and so the orang utans are left homeless. When the mother apes wander into the palm oil plantations they are often killed, and babies fetch a high price if sold to the idle rich in many countries – a man was recently apprehended at the airport with a drugged baby orang in a rattan basket. Fortunately, this little one was rehabilitated and will be released into the wild.

Sepilok has been remarkably successful at rehabilitating the baby orangs that it rescues. At first, the babies are completely cared for by humans, but once they are well they go through a programme of ‘skills training’, teaching them to climb, to identify the many different types of food that are available in the forest – each new baby is paired up with an older ‘buddy’ who teaches them the ropes. Eventually, they are released into protected forest, either at Sepilok or further afield. Visitors can only access a small part of the reserve and are confined to walkways. We are not allowed to get closer than 15 metres to any orangs that are hanging around – a Sepilok employee with a small bamboo stick will try to encourage the visitors to step back or move on, though some idiots do seem to think that their photos are more important. Generally the best views are at the feeding platforms – some food is left at these sites twice a day, so that newly released apes have a chance to supplement their diets. Apparently the food left here is deliberately monotonous, so that the orangs become bored and go elsewhere to forage.

While we were there, a wild mother brought her baby to the feeding sites. It is so moving to see the way that the baby was always in physical contact with his mum, keeping one hand entangled in her fur at all times.

A female baby will stay with her mother for about eight years, but the boys hang around for ten to twelve years – the outside world is a dangerous place for a young inexperienced male. There are no real predators of adult orang utans, apart from the odd enormous python (one that was nine metres long turned up at a logging camp), though clouded leopards will take a baby if they get a chance.

Orangs have the greatest difference in size between male and female of any ape – the big ‘flanged males’ are double the size of the females. Why has this happened? Firstly, not all males develop the typical fatty pads around their necks and throat that dominant males do – some males remain in a state of arrested development and are much less conspicuous. It’s these smaller, subordinate males that will force themselves upon  a lone female if they happen to find one. Females may prefer the big flanged males because they offer them more protection, and seem to be generally more appealing than the little guys – big males also have some unique vocalisations that they use to attract females, so maybe they are also honey-voiced seducers.

But why don’t all males develop fully? One reason probably relates to the nature of the forest that they live in. The majority of the trees there are known as dipterocarps (meaning ‘winged fruit’ – their seeds resemble those of the sycamore). These trees only fruit occasionally, sometimes every ten years, and all the trees in an area come into flower at the same time. This provides an occasional bonanza, but the rest of the time it’s slim pickings for all the animals. I suspect that the forest couldn’t support a population of orangs where all the males reached full maturity. I wasn’t lucky enough to see an adult male on this visit, but they are magnificent animals.

Photo One by Eric Kilby from Somerville, MA, USA / CC BY-SA (

Dominant Bornean Orang Utan male (Photo One)

Photo Two by Bernard Dupont, from

Subordinate male (Photo Two)

It was a real privilege to be able to watch these extraordinary animals at Sepilok, and we were very lucky – the reserve was closed to visitors because of Covid-19  the day after we left. I was pleased to see how carefully the staff were managing their interactions with the apes – keeping their distance and wearing proper face masks when they had to have hands-on contact with the youngest babies. Apes are extremely susceptible to our diseases, and even a coronavirus such as the common cold can be fatal for great apes – I dread to think what Covid-19 could do. I note that treks to see the mountain and lowland gorillas in Rwanda and Uganda have been suspended for a while, which is a relief. We have barely come to terms with the effect of the disease on other humans, let alone our closest relations.

Wild mother orang and baby at the nursery feeding station

Mother visiting the feeding station and spending time with her adolescent son.

Youngster just hanging around…

And I wouldn’t be Bugwoman if I wasn’t also intrigued by the insects. How about this chap?

Lantern bug

This is a true ‘bug’ of the Fulgoridae family, but although it is called a lantern bug it isn’t actually luminescent, and as far as I can see no one has worked out what the ‘nose’ is for. Still, it is a splendid insect, and apparently its mouthparts can tap directly into the sap of the tree. Very little is known about these insects, as is often the case in the tropics – there is such an abundance of species, and the habitat is so challenging, that these creatures are very under-studied. How splendid they are, though!

Malayan Owl butterfly (Neorina iowii)

And I managed to get a shot of the Malayan owl butterfly (Neorina iowii) – there were many, many beautiful butterflies and moths, but most of theme seemed to be on a mission and it was very difficult to keep up with them as they zoomed through the undergrowth. Plus, did I mention that Borneo has leeches? One wouldn’t want to career through a shrub without one’s leech socks on. Still, this butterfly, with its very pale eyespots, was most obliging. Its wings were like black-blue velvet.So, tomorrow we will remain at Sepilok, but we will leave the orang utans and make haste to see the sun bears at their rehabilitation centre just across the way. In the meantime, have an imaginary glass of Bornean ginger beer (ginger grows everywhere) and I’ll ‘see’ you soon.

3 thoughts on “The Orang Utans of Sepilok

  1. Anne

    Thank you. It has been a delight to tag along with you. I have only seen an orang utan at a zoo and that was decades ago.

  2. Pingback: Borneo – A Mother | Bug Woman – Adventures in London

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