Orangutan: Man of the Forest

It’s time we learnt a little about these very special creatures in the Borneo Rainforest, that we are observing at the moment here on the blog.

Yesterday we were wooed by all the cute photos of hairy mammals swinging from tree to tree and throwing bananas at each other. Today it’s time to learn a little about the man of the forest: The Orangutan.

Why is the Orangutan the Man of the Forest?

In Bahasa Indonesia (Indonesian language) orang means “man” and hutan means “forest”. Over time the ‘h’ was dropped and it became orang-utan: man of the forest. This name is very fitting as the orangutan is one of the closest living relatives to the modern human, sharing 96.4% of DNA.

The man of the forest is one of the largest primates in the world, measuring up to 1.25m in height and weighing up to 90kg, and is the only member of the great ape family that is found outside of Africa. Orangutans are found only in the rainforests of Borneo and Sumatra.

The orangutan was considered to be just one species until 1996 when it was divided into two species: the Bornean orangutan and the Sumatran orangutan. Of course, what we are observing in Borneo is the Bornean orangutan.


The Orangutan and its Habitat

The orangutan can’t survive just anywhere and has very specific habitat requirements. Part of the reason it is endangered is due to human activity destroying its natural habitat plus the orangutan’s lack of ability to adjust.

The orangutan lives in tropical and sub-tropical broadleaf forests in the Bornean lowlands. Being the most arboreal (tree-dwelling) of the great apes, it spends nearly all its time in the trees. The orangutan lives throughout the canopy of primary and secondary forests, and moves large distances to find trees bearing fruit.


Orangutans sleep in nests high in the trees. They make these nests every day and never use the same one for more than a few days.

Young orangutans learn nest-building from watching their mothers.

Orangutans are selective about the site of their nests even though many tree species are utilised.

The foundation is built by pulling together branches and joining them. After the foundation has been built, the orangutan bends smaller, leafy branches onto the foundation. This is called the “mattress”. Then the orangutan braids the tips of branches into the mattress. This increases the stability of the nest.


Orangutans may add additional features such as pillows, blankets, roofs and bunk-beds to their nest. Orangutans make “pillows” by clumping together leafy branches. They bite the twigs to blunt sharp ends. A “blanket” consists of large leafy branches with which they cover themselves after lying down. They may also create a waterproof overhead shelter for the nest by braiding together a loose selection of branches.

Much of these behavioural habits were not known until a few decades ago when research of orangutans began to take place and their behaviour studied. Primatologists like Dr. Birute Galdikas (founder of Camp Leakey in Tanjung Puting) are responsible for much of what we know today about orangutans.


The orangutan is an omnivorous mammal, though most of its diet constitutes fruit, nuts and leaves.

Being such a large creature, the orangutan spends much of its time eating or searching for food. The orangutan is an opportunistic forager, whose diet varies markedly from month to month depending on what is available.


Fruit makes up 65–90% of the orangutan diet, and those with sugary or fatty pulp are favoured. They eat both ripe and unripe fruits including mangoes, lychees, durian and figs which grow in abundance in the rainforest.

The durian is known as the “king of fruits”, possibly for its large size, strong smell, and unusual taste (ever seen those signs in hotels banning durians? That’s because they smell like a combination of sour milk, garlic and feet). The durian is one of the preferred fruits of orangutans. They discard the skin, eat the flesh, and spit out the seeds, acting as major seed dispersers for this fruit as well as for many others. In fact, orangutans are thought to be the sole fruit disperser for some plant species.


Semi-wild orangutans in Tanjung Puting are offered the chance to supplement their diet with bananas. Every day bananas are brought in by the boat-load and delivered to the feeding stations around Tanjung Puting National Park.

Each feeding station has its own feeding time and visitors to the national park can go to the feeding platforms to observe the orangutans as they climb down from the trees and help themselves.

As this is supplementary to the orangutans’ diet, the orangutans are free to come and go as they please and sometimes none show up at all at banana o’clock. And some show up only to gawp at the humans below gawping up at them. This is a good thing as it means that the orangutans are getting enough nourishment from the forest itself.

Reproduction and family

You might have noticed in many of my orangutan photos that often an adult orangutan appears with a baby orangutan clinging to it. This is because the young orangutan stays with the mother until up to 7 or 8 years of age.


In reproduction, orangutans are the primates most similar to humans: sexual maturity is reached at about 15 years of age and pregnancy lasts for nine months. Orangutans give birth to one offspring at a time and they have the longest inter-birth period of all the great apes: approximately eight years. A female orangutan has an average of three offspring during her lifetime.

An orangutan is completely dependent on its mother for the first two years of its life.  The mother will carry the infant during travelling, as well as feed it and sleep with it in the same nest. After two years it begins to learn to climb and will start to swing through the trees holding hands with other orangutans.

The young orangutan learns everything about survival, nest-building and climbing from its mother. The young one clings to its mother’s hair as she climbs the trees. The mother does not give birth to more young until the previous one is self-sufficient and independent.

The male orangutan plays no role in raising the young.

More about orangutans

If you want to learn more about these fascinating creatures, I recommend you check out the Orangutan Foundation International website.

And if you haven’t seen it yet, check out my photo post: Orangutan Antics.

This is just one post of twenty that make up the Rainforest Blog.
Read the rest of it here.
I would like to remind you that all the photos used on InMyShoesTravel are my own unless otherwise stated.
You can see my whole collection of Travel Photos here.

Filed Under: asiafeaturedIndonesiaKalimantanRainforestWildlife

About the Author: Based in Mallorca, obsessed with the world and have a lot to say about both... Step into my shoes and join me on a journey...

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