Once widespread throughout the forests of Asia, orangutans are now found on just two islands, Sumatra and Borneo. There are two genetically distinct species: the Sumatran orangutan (Pongo abelii) and the Bornean orangutan (Pongo pygmaeus). The two species look slightly different: Sumatran orangutans have lighter hair and a longer beard than their Bornean relatives, and Sumatran males have narrower cheekpads. Both species are highly endangered due to habitat loss and poaching.
Orangutans breed more slowly than any other primate, with the female having a baby on average only once every 7-8 years. Infants are dependent on their mothers for at least five years, learning about survival in the forest. Orangutans live for around 45 years in the wild, and a female will usually have no more than 3 offspring in her lifetime. This means that orangutan populations grow very slowly, and take a long time to recover from habitat disturbance and hunting.
The orangutan is one of our closest relatives in the animal kingdom, sharing 96.4% of our DNA. Indigenous peoples of Indonesia and Malaysia call this ape "Orang Hutan" which literally translates as "Person of the Forest".
Orangutans are unique in many ways. They are the only Great Ape in Southeast Asia, and the only Great Ape (other than humans) found outside Africa. They are the only 'red' ape, and the only strictly arboreal ape, meaning that they spend their lives in the forest canopy, even building nests in the trees in which to sleep. The other Great Apes (chimpanzees, bonobos and gorillas) do climb and build nests in the trees, but tend to spend their lives on the ground.
Orangutans also differ from the other Great Apes in that they do not live in family groups. The largest family unit is a female and two offspring, and males and females usually meet up only to breed. This semi-solitary lifestyle is thought to have evolved due to the unpredictability of available food. Orangutans primarily eat fruit, and spend up to 60% of their time foraging and eating.
Orangutans are highly intelligent and gentle animals. They use tools in the wild and have excellent memories, making mental maps of their forest home in order to find fruiting trees throughout the seasons.
Click here to find out why orangutans are critically endangered.
If you've ever wondered what an orangutan's longcall sounds like - listen to this!