The Orangutan

The Orangutan is found in South-East Asia, mainly Sumatra (Indonesia), and Borneo (Malaysia). They are the largest tree dwelling animals in the world and their preferred habitat is low-lying marshy swamps. They have adapted so that for some reason they never live in altitudes of over 800m.

They are frugivorous and over 400 food types have been recorded as part of an orangutan’s diet. In times of scarce food resources, the orangutans will not relocate, but will simply lower its food quality, to things like bark, termites and leaves. As well as acting as seed dispersers, orangutans allow light to reach the forest floor, which helps the plants growing below the canopy.

Fossils suggest that during the Pleistocene era (1.8 million years - 11,500 years ago) orangutans lived throughout much of Southeast Asia, from Java in the south, up into Laos and southern China.  In 1900, there were roughly 315,000 orangutans.

There are two different species of orangutan, the Sumatran orangutan, and the Bornean orangutan. Both have slightly different physical characteristics: Sumatran orangutans have a narrower face and longer beard than the Bornean species.  Bornean orangutans are slightly darker in colour and the males have wider cheek pads than their Sumatran relatives. Under the IUCN Red List, the Sumatran orangutan is classified as critically endangered and the Bornean as endangered.

The orangutan is semi-solitary — the largest group being a mother and two offspring.  Courtship lasts between 3-10 days and it is the female, who, not wanting to share her food, signals the “divorce”. The orangutan needs to forage for 60% of the day, with the other 40% spent sleeping and resting.

Orangutans are the slowest breeding of all primates and, at eight years, have the longest inter-birth interval of any land-based mammal. A  female orangutan will normally have her first infant between the ages of 12 and 15. Offspring are dependent on their mothers for at least five years and with a life expectancy of 45 years plus, females will normally have no more than three offspring. With these factors combined, the orangutan population, especially small fragmented populations, are at considerable risk.  They don’t have the capacity to recover from disasters that may strike a population. A slight rise in the adult female mortality rate by just 1-2% could drive a local population to extinction.

Illegal Logging In Indonesia, illegal logging has been a major and complex problem. An estimated 73-88% of all timber logged in Indonesia is illegal (2). Illegal logging has devastated protected areas, the last strongholds of orangutans. It occurred in 37 of 41 Indonesian national parks (2).

Oil Palm Plantations Indonesia and Malaysia are world’s largest palm oil producers and global demand for this commodity is increasing every year partly due to the expanding biofuel market. Orangutan populations are threatened because it is their habitat, tropical rainforest, which is being destroyed and converted to oil palm plantations. By the beginning of 2004, there were 6.5 million hectares of oil palm plantations across Sumatra and Borneo. Of this total area, almost 4 million hectares had previously been forested (3). Orangutans and the majority of biodiversity supported by tropical rainforests cannot co-exist with oil palm plantations. The use of fire to clear land for plantations is an additional risk to this already serious threat.

Forest Fires The fires of 1997 and 1998, and more recently in 2006, caused terrible destruction to Indonesia’s forests and killed, orphaned and displaced many orangutans. A combination of factors; dry debris from logging; use of fire by palm oil companies; and El Nino (which resulted in a longer than normal dry season) caused the fire to devastate a huge area of forest. Indonesia is the world’s third-largest emitter of greenhouse gases with 75% of its emissions as a result of deforestation. Forest fires and the decomposition of peatland add 2,000 million tons of CO2 to the atmosphere a year (4).


Illegal Mining Mining has caused irreversible damage to Indonesia’s forests. Tanjung Puting National Park, Indonesian Borneo has been exploited by illegal open cast mining for gold. It has turned the lush primary rainforest into a barren and lifeless desert. Mercury, used in the mining process, contaminates the river systems, killing fish & other wildlife.

The main threat to orangutans is habitat loss. However, this process of land clearing exposes wild orangutans and consequently some are shot. If infant orangutans survive the death of their mothers, they either end up as orphans in one of the rehabilitation centres or occasionally as a domestic pet.

Orangutan Rehabilitation

Rehabilitation is the process by which orphaned, confiscated or injured orangutans are returned to a life in the wild.  Usually, it starts when Forestry Department officials seize an illegally held orphan (orangutans are protected under law in Indonesia and Malaysia) and transfer he or she to a rehabilitation centre. Depending on the orangutans’ health and age they may require months of hand rearing and nursing. This can often mean 24-hour care. The young orangutans are subsequently given the opportunity to learn how to live in the wild. They are taken out into forests to taste wild fruit and practise climbing and to encounter the sights, sounds and smells they will eventually meet in the wild.  Once they are considered strong, healthy, proficient climbers, can make their own nests and find their own food, they will be moved to protected release sites.

Conservation or Welfare?
A common perception is that orangutan rehabilitation and orangutan conservation are one in the same. This is only partly true. The fundamental basis of orangutan conservation is habitat protection. If deforestation could be stopped so could the need for rehabilitation – as the number of orangutans being brought into care is only a reflection of the rate of habitat loss.  As Dr. Biruté Galdikas, President of Orangutan Foundation International (OFI), says “In the final analysis, orangutan rehabilitation has to be seen as a symptom of our failure to get to the underlying cause of the problem.”  While the plight of the orphan orangutans is a welfare crisis, the fact is reintroduced orangutans will not replace a wild population.
Originally rehabilitation was seen as a means of law enforcement, and thus as a form of conservation, as it allowed the authorities to confiscate illegally held animals.  However, after more than 40 years of orangutan rehabilitation, the number of orangutans in care is increasing, not decreasing, causing some people to question the efficiency of rehabilitation and whether it is actually helping save the species. 


Of course, the issue that underlies rehabilitation is that wild orangutans need to be better protected. Until they are, however, orangutans will continue to be killed and orphans will need to be rescued, so there remains the question of what to do with these animals?  They need to be taken into care – that is welfare.  But rehabilitation can potentially lead to direct conservation gains. Release sites need to be large and secure. Some reserves have been established especially for this purpose, thereby increasing the overall size of the protected area network.