/ ©: naturepl.com / Anup Shah / WWF-Canon

Orangutans

The lowland forest habitats of Asia's only great ape are quickly disappearing. The are being cut down for timber or burned to make way for oil palm plantations and other agricultural developments.

 / ©: naturepl.com / Anup Shah / WWF-Canon
© naturepl.com / Anup Shah / WWF-Canon
 rel=
Sumatran orangutan (Pongo abelii) female swinging through the trees with male baby. Gunung Leuser National Park, Sumatra, Indonesia.
© naturepl.com/Anup Shah / WWF

Key facts

  • Species

    Sumatran orangutan (Pongo abelii), Bornean orangutan (Pongo pygmaeus)

  • Location

    Sumatra (Indonesia), Borneo (Malaysia and Indonesia)

  • Status

    Endangered to Critically Endangered

Victims of logging and fire

Orangutans share a preference with humans for fertile alluvial plains and lowland valleys – a habitat once rich in tropical forests but now being replaced with logging and agricultural concessions.
 
Each of the two orangutan species is found only on the island from which it derives its name: Sumatra or Borneo. With numbers having fallen drastically over the past century and human pressures increasing, orangutans may be lost from the wild forever within a few decades.

Physical description 

The orangutan is the world's largest tree-climbing mammal. The animals have a characteristic ape-like shape, shaggy reddish fur and grasping hands and feet. Their long arms that can reach as much as 2 meters in length. Orangutans's legs are relatively short and weak, but their hands and arms are powerful.

There are 2 different types of adult male orangutan: "flanged" & "unflanged". Flanged males have a long coat of dark hair on their back, a facial disk, flanges and a throat sac used for “long calls". The unflanged male looks like an adult female. Both reproduce and an unflanged male can change to a flanged male for reasons that are not yet fully understood. Orangutans are the only primate in which this biological phenomenon occurs.

Size: 1.25-1.5m in length;  females weigh 30-50kg, males weigh 50-90kg

Colour: Reddish brown

The 'man of the forest'

Orangutans live in primary and secondary forests. Although they can occur up to 1,500 meters above sea level, most are found in lowland areas and prefer forests in river valleys or floodplains.

Orangutans travel about by moving from one tree to another, and usually avoid climbing down to the ground - although there are differences between the two species. When on the ground, they move on "all fours", with clenched fists placed on the ground.

Orangutans make a nest of vegetation to sleep in at night, and rest in smaller nets during the day to rest.

Social structure
Adult orangutans are generally solitary, although temporary aggregations are occasionally formed. The large home ranges of males overlap with the ranges of several adult females. Adult males are generally hostile to one another, although they do not display territoriality. 

Life cycle
Orangutans usually give birth to a single young, or occasionally twins. 

After weaning at about 3.5 years of age, young individuals become gradually independent of their mother after she gives birth to a second young. 

Orangutan females first reproduce at around 10-15 years of age, depending on the species/subspecies. Females give birth probably not more than once every 5 years, and the interbirth interval can be as long as 10 years.

The long time taken to reach sexual maturity, the long interbirth periods, and the fact that orangutans normally give birth to just a single young mean that orangutans have an extremely low reproductive rate. This makes orangutan populations highly vulnerable to excessive mortality, and means that populations take a long time to recover from population declines. 

Diet
About 60% of the orangutan's diet includes fruit (e.g. durians, jackfruit, lychees, mangosteens, mangoes and figs), while the rest comprises of young leaves and shoots, insects, soil, tree bark, woody lianas, and occasionally eggs and small vertebrates. They obtain water not only from fruit, but also from tree holes. 

Population & distribution

Previous population & distribution
Pleistocene fossil records in southern China, northern Vietnam, Lao PDR, and Java indicate that the genus once had a  wide distribution in Southeast Asia.

Orangutans are now only found on the islands of Borneo and Sumatra, with populations on each island belonging to separate species. A century ago there were probably more than 230,000 orangutans worldwide.

Current population & distribution
Both orangutan species have experienced sharp population declines over the past few decades.

Their dense forest homes make it difficult to precisely determine population sizes, however the Bornean orangutan is estimated to number about 41,000 individuals, while the Sumatran orangutan is estimated to number about 7,500 individuals.
Male Bornean Orang-utan (Pongo pygmaeus) / ©: David Lawson / WWF-UK
Flanged male Bornean orangutan (Pongo pygmaeus)
© David Lawson / WWF-UK

Habitat

Major habitat type
Tropical and Subtropical Moist Broadleaf Forests

Biogeographic realm
Indo-Malayan

Range States
Indonesia, Malaysia

Ecological Region
Borneo Lowland and Montane Forests, Kinabalu Montane Shrublands, Sundaland Rivers and Swamps
Tree emerging from tropical rainforest. Gunung Leuser National Park, Sumatra, Indonesia.  / ©: Alain Compost / WWF-Canon
Tree emerging from tropical rainforest. Gunung Leuser National Park, Sumatra, Indonesia.
© Alain Compost / WWF-Canon

What are the main threats?

Habitat loss
Habitat destruction and fragmentation is by far the greatest threat to orangutans.

Huge tracts of forest have been cleared throughout the their range, through legal and illegal logging and forest conversion for oil palm plantations and other agriculture. Fires related to these activities also pose a serious threat to both orangutans and their habitat.

Today, more than 50% of orangutans are found outside of protected areas, in forests under management by timber, palm oil and mining companies.

Hunting & illegal trade
Orangutans are an easy target for hunters, being large and slow targets. 

The animals are killed for food in some areas, or in retaliation when they move into agricultural areas and destroy crops. This occurs more in times of environmental stress when orangutans can't find the food they need in the forest.

Females in particular are most often hunted. When caught with offspring, the young are often kept as pets.

This pet trade is a major problem. It is thought that for each orangutan reaching Taiwan (China) as many as 3-5 additional animals die in the process. Recent enforcement of the law in Taiwan has reduced the importation of orangutans, but the trade remains a threat in Indonesia where there is still demand for orangutans as pets.

There is also trade in orangutan skulls in Kalimantan (Indonesian Borneo). 

 / ©: Alain COMPOST / WWF-Canon
Loggers clearing a swamp forest for a palm oil plantation. (Illegal logging) Central Kalimantan, Indonesia.
© Alain COMPOST / WWF-Canon
 / ©: Chris R. Shepherd - TRAFFIC Southeast Asia
A Sumatran orang-utan, confiscated in Aceh, stares through the bars of its cage
© Chris R. Shepherd - TRAFFIC Southeast Asia

What is WWF doing?

WWF has been working on orangutan conservation since the 1970s, in partnership with both international and local groups including research institutions, universities, government institutions and local communities. This work is guided by a specific Species Action Plan for orangutans, and includes:
  • Conserving orangutan habitat: We are working in both Borneo and Sumatra to secure well-managed protected areas and wider forest landscapes connected by corridors.
     
  • Promoting sustainable forestry and agriculture: Our work on sustainable production of commodities – including forest products and palm oil – also contributes towards the protection and conservation of major orangutan habitats on the islands, as well as to mitigating human-orangutan conflict.
     
  • Halting the pet trade. We work with TRAFFIC (the wildlife trade monitoring network) to help governments enforce restrictions on the trade in live animals and orangutan products. We also help to rescue orangutans from traders. Many are taken to refuges where they can recover and be rehabilitated, and are eventually released back into the wild. 

» More on our orangutan work in Borneo 
» More on our orangutan work in Sumatra

Priority species

As a great ape, orangutans are a WWF priority species. WWF treats priority species as one of the most ecologically, economically and/or culturally important species on our planet. As such, we are working to ensure orangutans can live and thrive in their natural habitats.

You can help

  • Adopt an orangutan through WWF-UK or WWF-US and support our work to protect orangutans (international adoptions possible)

Make a donation

Did you know?

    • Orangutans are “gardeners” of the forest, playing a vital role in seed dispersal.
       
    • Released captive orangutans have been reported to use sticks for digging, fighting, prying, eating, scratching, and many other purposes.
       
    • Some released individuals learned independently to untie complex knots that secured boats and rafts, and then to shove off, board, and ride the vessels across rivers.
       
    • Wild orangutans have also been observed making tools to scratch themselves, using leafy branches to shelter under, and using branches for foraging, honey collection etc. 

Please Donate

  • Our work is only possible with your support.

    Donate now

Subscribe to our mailing list

* indicates required
Donate to WWF

Your support will help us build a future where humans live in harmony with nature.