10 Interesting Facts About Orangutans
An Endangered Cousin
We humans sometimes often like to think of ourselves as something special, somehow separate from the rest of life. Often when we refer to the animal kingdom, we think of it as some separate or even inferior concept. We have a tendency to refer to everything from bees to chimps as "animals" while keeping ourselves separate. It seems a rather odd thing to do because, in fact, we share more than 90 percent of our DNA with the great apes. We are more closely related to chimps and gorillas than lions are to tigers, and they can still breed with each other.
Over the years, we humans have gradually come to understand the wild habits of chimpanzees, gorillas and the other ape, the acrobatic gibbon, but the life of the orangutan, even to this day remains somewhat of a mystery even to the most passionate and devoted of experts. But at least here, in this article, we can acknowledge that we know a lot more about orangutans than we did half a century ago. Below, I will outline ten interesting and key facts that we definitely know about wild orangutans, as well as some of the most interesting and perplexing mysteries that still surround these so called 'men of the forest.'
The Orangutan SubspeciesClick thumbnail to view full-size
The Males Cheek Pads
Mother and Baby
- A solitary ape: In the wild, orangutans are generally solitary creatures, or semi-solitary at least, which is quite unlike any other ape, or indeed most other of the so-called ‘higher’ primates (apes and monkeys). Once they reach maturity, they spend most of their time alone, or in the case of females with their offspring. The large adult males with fully developed cheek pads take solitary living to the extreme, spending up to 90 percent of their time completely alone.
- Two sub-species of orang-utan: Orangutans today live on just two islands, Borneo and the northern area of Sumatra. The two populations have lived separately from each other for nearly two million years, and in that time have evolved into separate subspecies. At first glance, it can be hard to tell them apart, but there are some subtle differences. The Bornean’s have quite a square head, while the Sumatran’s heads are generally taller, more diamond shaped, with much smaller cheek pads and vocal sacs. The Sumatran’s also boast splendid beards which are absent in the Bornean subspecies. The Bornean and Sumatran orangutans are actually relics of a range of subspecies that once inhabited great swathes of Asia including southern China, Java, Vietnam and southern Sumatra, but sadly the rise of the human population and the loss of habitat mean that the species is now entirely absent from its prehistoric range.
- The largest arboreal animal: Orangutans are the largest arboreal or tree dwelling animals on the planet, while it is true that even large male gorillas occasionally climb trees in order to feed, they are not a true arboreal animal and spend most of their time on the ground. Adult male orangutans, on the other hand, spend over 90 percent of their time in the canopy despite weighing around 300Ib’s. Adult females spend even more time in the canopy, mostly eating ripe fruit, young leaves and maybe the occasional vine or termite.
- Cheek-pads: Adult male orangutans develop cheek pads, which serve to frame the face, making their heads appear much larger than they actually are. In captivity, males have been known to develop cheek pads as young as 13, but more typically the pads don’t appear until around the age of 30. Once a male has gained his cheek pads, he will not tolerate any other males in his immediate vicinity and will compete with them for the attention of the females. The cheek pads also help to enhance the males’ booming call, which he uses to broadcast his presence through the dense forest.
- Males and females: Of all the primates, the orangutan experiences the most pronounced sexual dimorphism, with the large males being three times bigger than the females. As well as their cheek pads, they also sport a throat pouch that acts as a resonating chamber for his loud call. He also possesses a highly muscular body which forms as a result of a testosterone surge in the latter stages of adolescence.
- Mother and young: Orangutans have the most intense relationship between mother and young of any mammal except humans. Females will carry their offspring for around five years and may suckle them for up to seven years. For a young orangutan, its mother is the only companion it will have for about eight years. In fact, mother and young will sleep together in the nest every single night until another infant is born. All in all, it can take as much as 13 or 14 years, for a young orang-utan to feel confident enough to leave its mother.
- Time between births: Of all mammals, the orangutan has the longest birth interval, often giving birth on average, once every eight years. Although, in Sumatra, some females may wait as long as a decade between births. In fact, this is one of the factors that make orangutans especially vulnerable to extinction; the other key factor is that females often don’t start breeding until the age of 17, which means that if a significant number of adult females are killed, then it can take decades for a population to recover.
- Asia’s great ape: Orangutans are the only great apes to be found anywhere in Asia. Their far distant ancestors originally lived in Africa, but dispersed from there some 15 million years ago during the Miocene period. At this time, there were many different species of ape living all across Africa, Asia and even parts of Europe which enjoyed a balmy climate at this point. However, the coming of the ice ages would spell the end for most of these ape species, except of course the ancestors of the modern great apes, including us.
- Gentle giants: Orangutans, along with gorillas are the most gentle natured of all the apes and will often sit for hours simply gazing at nothing in particular. Attacks by orangutans on humans are virtually unheard of; contrast this to the chimpanzee whose aggression towards each other and humans is well documented. This aggression can manifest itself even in chimps that have been lovingly cared for by humans in captivity.
- Intelligence: Like all great apes, orangutans are exceptionally smart and can easily match their more high profile African cousins in cognitive tests. In captivity especially, they demonstrate exceptional tool making ability and versatility. One captive bred orangutan was even taught how to chip a stone hand axe. In the wild, one particular population makes and uses tools specifically for extracting fruit, except that, unlike chimps, they hold the tools in their mouths.
Amazing Footage of an Orangutan Narrated by Sir David Attenborough
What We Don't Know About Orangutans
1. Why are they orange? So why are orangutans orange when their chimp and gorilla cousins are black? Well, whilst their fur blazes bright orange in direct sunlight, once they retreat into cover, their tan skin absorbs the light, so you don’t see their sparse hair, but rather their dark skin, so effectively, they become black. Perhaps this remarkable change in colour is somehow adaptive in some way, or is the bright orange fur some sort of signalling device for when these normally solitary primates come into contact with other individuals.
2. Their life expectancy in the wild? In captivity, orangutans routinely live well into their 60's. Studies have shown that females born in the late 1960’s in parts of northern Sumatra are still fit, healthy and bearing offspring. It could well be that they live as long as 70, but truthfully we cannot say for certain.
3. How far do the males travel in a lifetime? Male orangutans travel much greater distances during their lifetime than the females. According to experts, they may travel as much as several hundred miles from their mother’s home range. Indeed, one particular male in northern Sumatra was documented as having travelled more than 20 miles away from his mother in just one year. So it’s likely, that a large portion of males may travel more at least 100 miles away from their mothers.
4. Have they always been solitary? It’s possible that back in prehistory the orangutan was far more gregarious than they are at present, and indeed captive-bred individuals that have been released back into the wild tend to be more gregarious than their wild contemporaries. Perhaps, in the past when orangutans lived in fertile lowland areas with abundant food, they were far more social and gregarious. Since then though, humans have steadily destroyed the forests to make way for agriculture, those fertile and abundant areas soon disappeared along with the social orang-utan, that it’s if they existed in the first place.
5. Extinction- will they survive? This is the million dollar question when it comes to orangutans. In a comparatively short space of time, vast swathes of their habitat in Borneo and Sumatra have been catastrophically destroyed. Many people are working very hard to save the species and its habitat, but as is always the case with conservation there are many forces and factors that hinder any sort of protection and recovery. Indeed, it seems that many of these forces and factors just simply work against the orangutan. It may well be that, if we are lucky we can save maybe one of two wild populations, with the rest living out their lives in a captive environment.
More on Orangutan Conservation
- Orangutan Land Trust | Sustainable solutions for the long-term survival of the orangutan in the wild
An organisation that serves to provide permanent solutions for the survival of the orangutan in the wild by safeguarding suitable habitat.
- Orangutan Foundation, Conservation, Research, Education, Rehabilitation
Orangutan Foundation is the world's foremost orangutan conservation organisation, saving Asia's endangered great ape by protecting their tropical forest habitat, working with local communities and promoting research and education.
- Orangutan Foundation International - Research, Conservation, Education
Learn all about orangutans and what we are doing to protect and study them and their only habitat, the tropical rainforests of Borneo and northern Sumatra.