The Bornean orang-utan (Pongo pygmaeus) and Sumatran orang-utan (Pongo abelii) are classified by the World Conservation Union (IUCN) as endangered and critically endangered respectively. Based on the data obtained from WWF, there are approximately 7,300 Sumatran orang-utans and between 45,000 to 69,000 Bornean orang-utans left in the wild.
The Malay word orang-utan means the “person of the forest.” These orang-utans are found only in Sumatra and Borneo. They are highly intelligent and are close relatives of humans sharing close to 97% of the genetic makeup of human beings.
Orang-utans have an enormous arm span. A male may stretch his arms approximately 2.1 meters from fingertip to fingertip. This is a reach considerably longer than his standing height of about 1.5 meters. When orang-utans do stand, their hands nearly touch the ground.
The arms of the orang-utans’ are well suited to their lifestyle because they spend close to 90% of their time in the trees of the tropical rainforest. They even sleep aloft in nests of leafy branches. They use large leaves as umbrellas and shelters to protect themselves from the common rains.
The orang-utans forage for food during daylight hours. And most of their diet consists of fruit and leaves gathered from the trees of the rain forest. On rare occasions, they eat bark, insects and meat.
In general, orang-utans are solitary primates. The males are loners. As they move through the forest, rumbling and howling calls are made to ensure that they stay out of each other’s way. These calls can be heard about 2 kilometres away.
On the other hand, mothers and their young, share a very strong bond. Infants will stay by their mother’s side for 6 or 7 years until they develop survival skills. Female orang-utans give birth only once every 8 years. This is the longest time period of any given animal. These primates are long-lived and can survive as long as 60 years in captivity.
As orang-utans live in only a few places, and because they are highly dependent on trees, they are especially vulnerable to logging, deforestation and other human activities, such as hunting and illegal pet trade. These activities have placed the orang-utan population in dangers of extinction.
Particularly the Sumatran orang-utans, which is considered critically endangered, if logging and hunting activities ceased, only populations of 250 or more will have prospects of long-term viability. However, if the activities persist on, the Sumatran orang-utan population will drop by 50% in a decade and by 97% in 50 years, eventually going extinct.
Geographical Location
Borneo
Borneo is the third largest island in the world and it is east of Singapore. It is divided among Brunei, Malaysia and Indonesia, with the majority in Indonesian territory. Borneo is home to one of the oldest rain forests in the world, at approximately 130 million years old.
Sumatra
Sumatra is an island in Indonesia and it is south of Singapore. It has lost almost half of its tropical rain forest in the last 35 years and many of its species are endangered. Besides the orang-utan, the Sumatran tiger and Sumatran rhino are endangered as well.