Habitat loss is by far the greatest threat to orang-utans. Huge tracts of forest have been cleared throughout their range and the land used for agriculture, particularly palm oil plantations.

Road development, illegal timber harvesting and unsustainable logging, mining and human encroachment also contribute to habitat loss, degradation and fragmentation. Today, more than 50% of orang-utans are found outside of protected areas in forests under management by timber, palm oil and mining companies.

But even protected areas are not secure since their boundaries are often not clearly delineated, which makes them difficult to safeguard and patrol. Furthermore, many parks are understaffed and underfunded. Consequently, oil palm companies and logging firms have been able to encroach on protected areas.

Along with the destruction of their forest homes, orang-utans up to the age of seven are sought after for the illegal pet trade. When infants are targeted, the traffickers usually kill their mothers so the trade represents a real threat to wild orang-utan populations.
 
In addition, orang-utans are hunted in some areas for food or occasionally killed when they venture onto agricultural areas and damage crops. Fire is also a major threat.
 

Conserving orang-utan habitat: We are working in both Borneo and Sumatra to secure well-managed protected areas and wider forest landscapes connected by corridors.
 
Promoting sustainable palm oil production: In 2004, WWF helped set up the Roundtable on Sustainable Palm Oil. This promotes the production and use of sustainable palm oil, which ensures that income is filtered down to local people and forests that are deemed to be of ‘high conservation value’ are not cut down to make way for oil palm plantations.
 
Engaging with timber companies: WWF is working with companies to mitigate the negative impacts of logging and timber plantations on habitats and orangutan populations. For example, studies show that Bornean orang-utans can fare well in logged forests if the impact is reduced through measures such as selective logging, keeping fruit trees intact, and controlling hunting.

Halting the illegal pet trade: WWF works with TRAFFIC (the wildlife trade monitoring network) to help governments enforce restrictions on the trade in live animals and orang-utan products. We also help to rescue orang-utans from traders.

Reducing human orang-utan conflicts: We work with governments, communities and plantation owners on practical methods to keep orangutans out of plantations as well on regional land use planning to ensure that agricultural areas are developed as far away from orang-utan habitat as possible.
 

Physicial description

Orang-utans have a characteristic ape-like shape, shaggy reddish fur and grasping hands and feet. Their powerful arms are stronger and longer than their legs, and their hands can touch their ankles when they stand.

There are two different types of adult male orang-utan: flanged and unflanged. Flanged males have prominent cheek pads called flanges and a throat sac used to make loud verbalizations called 'long calls'. They also have a long coat of dark hair on their back.
 
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.

Male orang-utans can tip the scales at 90 kg, while females weigh between 30-50 kg. 

Life cycle

Orang-utans can live up to 50 years in the wild. Females first reproduce between 10-15 years of age. They give birth at most once every 5 years, and the interval between babies can be as long as 10 years.
 
Orang-utans usually give birth to a single young or occasionally twins. Orang-utans stay with their mothers for the first 7-11 years of their life. An infant rides on its mother and sleeps in her nest until it is able to survive on its own.

The long time taken to reach sexual maturity, the long interbirth periods, and the fact that orang-utans normally give birth to just a single young mean that orangutans have an extremely low reproductive rate.
 
This makes orang-utan populations highly vulnerable to excessive mortality, and means that populations take a long time to recover from population declines.
 
About 60% of the orang-utan's diet includes fruit, such as durians, jackfruit, lychees, mangosteens, mangoes and figs. The rest comprises 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 and distribution

Orangutans were once distributed widely across Southeast Asia, roaming as far north as southern China, and as far south as the Indonesian island of Javar. But today Asia's great ape is confined to just two islands, Borneo and Sumatra.

A century ago, there were probably 230,000 orangutans - around four times as many as there are today.

Their dense forest home makes it difficult to determine population sizes, but the Bornean orangutan is estimated to number around 54,000 individuals, while there are an estimated 6,600 Sumatran orangutans.

The Sumatran orangutan is now restricted to the north of Sumatra. It depends on high-quality primary forests, and is less able to tolerate habitat disturbance than Bornean orangutans. Sumatran orangutan densities reportedly fall by up to 60% with even selective logging.

The population is fragmented into 13 populations but only 6 of them boast more than 250 animals and are therefore regarded as viable in the long term. However, even these populations are under threat due to ongoing habitat loss.

The Bornean orangutan was once distributed throughout large areas of Kalimantan (Indonesia) and Sarawak and Sabah (Malaysia) on the island of Borneo. But its population has fallen by more than 50% over the past 60 years, while at least 55% of its habitat has disappeared over the last 20 years.

Most Bornean orangutans are now found in Kalimantan, especially along the east coast. The majority of wild populations are located outside of protected areas, in forests that are exploited for timber production or are in the process of being converted to agriculture.

Three subspecies live in different parts of the island - the Northwest Bornean orangutan is the most threatened, the Northeast Bornean orangutan is the smallest in size, and the Central Bornean orangutan is the most common.