There are two sub-species of orangutan found in the world, both in Indonesia but one on the island of Borneo and the other on the island of Sumatra.

Sumatran orangutan spend most of their time up in the trees and very little time on the ground (they are arboreal). This is probably because unlike on Borneo, Sumatran orangutan share their forest with some fearsome ground-dwelling predators – the Sumatran tiger and rhino. So they prefer to stay up in the trees, feeding mostly on fruit, insects and small invertebrates. They can move easily through the forest swinging on their long arms, and build nests to sleep in and eat. The orangutans in Sumatra have been seen using tools, such as especially chosen and prepared sticks to fish termites out of their mounds or honey out of beehives, and using large leaves to protect themselves from heavy rain. Although there are similar situations and materials available on Borneo, orang-utans here have not been seen using tools.

Orangutans were for a long time thought to be solitary, but we now know that this only applies to those on Borneo. Sumatran orangutans are much more social, often gathering in large groups when certain fruits are in abundance. A female gives birth to one baby every 8-9 years, the longest interbirth rate of any of the great apes. This makes them relatively slow to reproduce the next generation and so more vulnerable to extinction; each individual becomes very key to the survival of the species.

Why are they endangered? 


The Sumatran Orangutan is endemic to Sumatra, which means it is only found on that island. Any endemic animal is particularly threatened with extinction because there is such a small population. Today it is only found in the north of the island, in the Aceh region. Orangutans are hunted, often to be kept as pets and status symbols in homes. But the primary reason for its decline is deforestation to make way for palm oil plants, which is used in a lot of food products. With no primary rainforest to live in, the orangutans have nowhere to call home.

Where can I find out more?

There are a lot of charities working with Sumatran Orangutans:
Sumatran Orangutan Society
Sumatran Orangutan Conservation Programme
Orang-utan Health Project

What can I do to help?

Stop using any product which contains palm oil, you’ll be surprised how many do. Telling your friends about it will help to spread the word, or look out for campaigns to add your name to. A lot of the charities working with orangutans have volunteer programmes, click on the links above.