orangutanScientific Name: Pongo pygmaeus (Bornean) Pongo abelii (Sumatran)

Status: Both sub-species are endangered

Appearance

Orangutans are covered in long red-brown hair that looks like it is in dreadlocks. They have a large body, thick neck, very long arms, short bowed legs and they have no tail. They have a large head with a big mouth area. The adult male orangutans have large cheek flaps and these get bigger as the orangutan gets older. The arms of an orangutan are twice as long as what their legs are. They have curved fingers and toes that can help them to grip onto branches better. Orangutans walk on their fists not their knuckles like gorillas and chimpanzees.

The average height of a male orangutan is 1.4 metres and they weigh about 90 kilograms. The female orangutan is much smaller and their average height is about 1 metre and they weigh about 50 kilograms. They have an opposable thumb on their foot which they can use just like a hand to grab onto branches to move through the rainforest.

Lifespan

Orangutans live to about 35 to 40 years in the wild and they can live up to 60 years in captivity.

Diet

Fruit is the main part of the orangutans diet and makes up about 65 – 90 percent of what they eat. They mostly favour ficus fruits because they are easy to get and easy to digest. The lowland forests are where they like to live because there is a lot of fruit there. Orangutans have been known to eat leaves, shoots, insects, honey and bark. Orangutans don’t have to leave the trees to be able to drink because they get water that has collected in the holes in the trees. They also drink from rivers if they are near to them.

Habitat

Orangutans in the wild are now only found in tropical rain forests on the islands of Borneo and Sumatra in Indonesia. They have been exterminated from lowland forests in Sumatra, and same has nearly happened in Borneo. This is because the forests are being cleared to agriculture to produce such things as palm oil, rubber and pulp. Farming, logging and burning of the forests have destroyed about 80% of the rain forests where the orangutans used to live. Palm oil plantations are also responsible for a lot of the loss of habitat of the orangutan because it is used in many everyday products that we use and the forests are cleared to make way for these plantations. Also poachers kill some of the orangutan mothers and then sell their young for pets illegally.

Reproduction

Males reach the age of maturity and are ready to reproduce at about 15 years of age and females are ready at about 12 years of age. Female orangutans have a menstrual cycle of about 22-30 days. The gestation period for the orangutan is about nine months. The females only give birth to a baby about every six or eight years. They usually have one baby at a time sometimes two. The average size at birth is 1.5 to 2 kilograms. When a baby orangutan is born it can’t do anything for itself. They usually stay with their mother for around eight years before they go on their own, this is because they don’t live in large groups so they have to learn how to survive from their mother. For the first few weeks of life the baby hangs onto its mothers stomach and then when it gets older it learns to piggyback on its mother.

Orangutan

Behaviour

Orangutans are more solitary creatures than any of the other great apes. Adult males and male and female adolescents live alone. Females live in home ranges with their offspring and these usually overlap with the home ranges of other females which may be relatives such as their mothers or sisters. Even though they generally live a solitary life they are still quite social, and when they cross each others path they will have brief social interactions.

They communicate using hoots and hollers, and the males communicate with a special vocalization called a long call. This call lasts up to about two minutes and is probably used to warn other males and to signal females during the mating season.

The orangutan is the ape most inclined to a life of the trees. They will rarely descend from the tree tops.

Predators of the orangutan include clouded leopards, wild dogs, crocodiles and their biggest threat the tiger. Bornean orangutans are found on the ground more as there are no tigers on this island.

Quick Facts

Orangutans arm spam is longer than their height, which is good for their lifestyle of living in the trees.

Orangutan means ‘person of the forest’ which is derived from Malayan of orang (person) and utan (forest).

When they are about 15 years old the males develops cheek pads, and the female orangs find these very attractive.