Orang Utan Borneo

Orangutans – The Great Apes of Borneo

Orangutans are native to Borneo & Sumatra

Orangutans habitat are found only in the rainforests of the Southeast Asian islands of Borneo and Sumatra. They spend nearly their entire lives in trees — swinging in tree tops and building nests for sleep.

The two species of orangutans, Bornean and Sumatran, are slightly different in appearance and behavior. While both have shaggy reddish fur, Sumatran orangutans have longer facial hair and seem to have closer social bonds than their Bornean cousins.

  • Pongo pygmaeus pygmaeus (From Borneo, with a round face and dark red hair)
  • Pongo pygmaeus abelii (From Sumatra, with a narrow face and paler hair)

The Bornean and Sumatran species have formed separate breeding populations over a million years, diverging in genetics, behaviour, diet, life history and morphology. Neither species is territorial, but fully developed adult males tend to avoid one another, and sometimes fight if they meet.

Bornean orangutans are more likely to descend from trees more often than the Sumatran and move around on the ground. Both species build fresh sleeping nests from branches and leaves almost every evening. Each evening, orangutans will construct a “nest” in the tree branches for the night in which they will curl up and sleep. These nests are made out of leaves and branches. Nests are shared by a mother and her nursing offspring. Sometimes, the orangutan will use a leaf as a “roof” to protect itself from the rain. Orangutans often nap in the afternoon after a morning spent obtaining food.

Orang Utan and Baby
Orangutan mother and child

Behaviours and Biology

Orangutans are shy, solitary animals that are active during the day (they are diurnal). They live alone in large territories. This is probably due to their eating habits; they need a large area in order to get enough food and too many orangutans in one area may result in slow starvation.

The only long-lasting orangutan social group is the mother and her child, who will live together for about 7 years. When mating, the male and female orang utan might stay together for only a few days.

Orangutans are mature and capable of reproducing beginning when they are 7 to 10 years old. Females are pregnant for 8.5 to 9 months and give birth to a single baby. Young orangutans are weaned from their mothers at about 6-7 years of age.

Fruits makes up about 60% of the orang utan’s diet.  In the wild these mostly include lychees, mangosteens, mangoes and figs. They also eat young leaves and shoots, insects, soil, tree bark, and occasionally eggs and small vertebrates.  Their water supply comes from fruit as well as from leaves and tree holes.

Mature Orang Utan
An orangutan eating fruit

An Endangered Species

The Bornean Orangutan is listed as “Endangered” with perhaps 41,000 population remaining, while the Sumatran orangutan is considered “Critically Endangered” with an estimated numbers of only 7,500 left. A century ago, it is likely that more than 230,000 orang utans roamed in the rainforests.

Orangutans populations are decreasing in numbers quickly as they lose habitat to people – especially from the incursion of large scale palm oil plantations. Further aggravating the problem, baby orangutans are caught and sold around the world as pets. Sanctuaries and rehabilitation centres such as the one at Sepilok have been setup in Malaysian Borneo to rescue young orang utan who have lost their natural habitat.

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