Bornean orangutans (Pongo pygmaeus) are currently found on the Southeast Asian island of Borneo and generally inhabits swampy and hilly tropical rainforests. Bornean orangutans have a patchy distribution throughout the island and is completely absent from the southeast region. Fossil evidence suggests that Bornean orangutans were once widespread throughout Southeast Asia and evenly distributed across the entire island of Borneo. Due to illegal logging and the destruction and conversion of tropical forest to agricultural land this once expansive range has decreased dramatically.
Biogeographic Regions: oriental (Native )
Other Geographic Terms: island endemic
Species distribution is now highly patchy throughout the island: it is apparently absent or uncommon in the south-east of the island, as well as in the forests between the Rejang River in central Sarawak and the Padas River in western Sabah (including the Sultanate of Brunei).
Bornean orangutans have orange-red hair and long arms, which are advantageous for traveling through the canopy. Bornean orangutans grasp with both their feet and hands, which suites their arboreal life. Both sexes have throat pouches for calling but the male’s throat pouches are larger than the females. Bornean orangutans are sexually dimorphic, with males having an average height and weight of 970 mm and 87 kg respectively, and females averaging 780 mm and 37 kg, respectively. Males also develop large cheek pads known as flanges and develop a sagittal crest where large temporal muscles attach.
Bornean orangutans exhibit bimaturism, or two different forms of mature males. These two types of males are denoted as being either flanged and unflanged. Flanged males are twice the size of females, have a large facial disk with flanges, and a large throat patch. Unflanged males look much more like the females as they are the same size and do not display the same calling behavior as flanged males. Both types of adult male orangutans reproduce in the population. Unflanged males may become flanged at any time, as it is a reflection of social hierarchy as well as age. Males between 8 and 15 years of age are generally unflanged and become flanged between 15 and 20.
Bornean orangutans are distinguishable from their Sumatran cousins in their morphology. After diverging 1.5 million years ago, Bornean orangutans have become heavier and thicker, have darker red coats, long course hair, and the males have larger flanges covered in bristly hair and larger throat pouches.
Average mass: 87 kg.
Average length: 970 mm.
Sexual Dimorphism: male larger; ornamentation
Other Physical Features: endothermic ; bilateral symmetry
Average mass: 64475 g.
Bornean orangutans are arboreal and rarely descend to the ground. They generally live in the old growth forests ranging from the lowland swampy areas to the dipterocarp forests. The peat swamps and flood-prone dipterocarp forests produce more fruit than the dry dipertocarp forests and have a higher density of Bornean orangutans because they migrate depending on fruit availability. Bornean orangutans inhabit the primary tropical rainforest and secondary forest at lower elevations and are rarely seen above elevations of 1000 meters.
Range elevation: 0 to 1000 m.
Average elevation: <500 m.
Habitat Regions: tropical ; terrestrial
Terrestrial Biomes: rainforest
Habitat and Ecology
The orangutan is the only primate species with two different forms of mature males (bimaturism). Flanged males are twice the size of the female; they possess a long coat of dark hair on the back, a facial disk, flanges and a throat sac used for “long calls”. These males are rather intolerant and aggressive towards other adult males. Unflanged males do not possess these secondary sexual characteristics; they are the size of an adult female, they do not emit long calls nor do they show mutual intolerance. These two types of male both sire offspring and contribute to the reproduction of a given population (Goossens et al. 2006a). The transition from the unflanged to the flanged form can happen anytime; this depends mostly on complex social cues that are not yet fully understood.
Bornean orangutan distribution is patchy throughout the island. Large rivers are impassable natural barriers and limit their dispersal (Goossens et al. 2005). The species occurs typically at relatively low abundance in the Bornean forests: from 0.5 to 4.0 ind./km² in most populations (review in Singleton et al. 2004, van Schaik et al. 2005). Bornean orangutans are more abundant in low-lying forests (below 500 meters asl) than in uplands. Flood-prone forests and peatswamps produce more regular and larger fruit crops than dry dipterocarp forests and harbour the highest orangutan densities. Bornean orangutans are vulnerable to habitat disturbances, although the taxon P. p. morio shows a relative and unexpected tolerance to habitat degradation in the northern part of the island (Ancrenaz et al. 2005).
Females generally give birth to a single infant after a gestation period of approximately 245 days (Nowak 1999). Female Bornean orangutans reach maturity between 10 and 15 years old and reproduce every six to eight years on average (Nowak 1999, Wich et al. in press).
Bornean orangutans are frugivorous, and spend two to three hours in the morning feeding avidly. Their diet consists of forest fruits, leaves and shoots, insects, sap, vines, spider webs, bird eggs, fungi, flowers, barks, and occasionally nutrient rich soils. Bornean orangutans have been documented eating more than 500 plant species as part of their diet. Fruits make up more than 60% of their total dietary intake and they will migrate depending on fruit availability.
Animal Foods: eggs; insects; terrestrial worms
Plant Foods: leaves; roots and tubers; wood, bark, or stems; fruit; nectar; flowers; sap or other plant fluids
Other Foods: fungus; detritus
Primary Diet: herbivore (Frugivore )
Since fruits make up more than 60% the Bornean orangutan diet, they play a vital role in seed dispersal, especially for the larger seeds which cannot be dispersed by smaller animals. Bornean orangutans play such a crucial role in seed dispersal that they have been given the title "gardeners of the forest".
Ecosystem Impact: disperses seeds
The only predator of Bornean orangutans are humans. Even hunting for traditional purposes at a 2% hunting rate, is not sustainable for the current population of orangutans. Bornean orangutans are not subject to predation from large felines like their Sumatran cousins, although clouded leopards are able take down a young Bornean orangutan.
- humans (Homo sapiens)
- clouded leopards (Neofelis nebulosa)
Anti-predator Adaptations: cryptic
Life History and Behavior
Bornean orangutans are not as social as other species of great apes and do not have as many social vocalizations. The most prominent form of communication for Bornean orangutans is the long-call, a one to two minute call performed only by flanged males. The long-call can be heard from several kilometers away in the right conditions. The main purposes of long-calls are to inform other males of the caller's presence (when unflanged males hear long-calls they flee the area) and to call out to sexually responsive females. Long-calls are spontaneous and do not follow any specific pattern. Some evidence suggests that the long-call can even suppress the development of unflanged males. When the unflanged males hear a long-call, stress hormones are produced which inhibit the development of the unflanged males. The other type of calling produced by Bornean orangutans is a fast-call, which is most often made after male-to-male conflict. In addition to the long and fast calls, Bornean orangutans smack their lips to produce sounds when in small social groups. When scared, Bornean orangutans will funnel their lips and scream.
Communication Channels: visual ; acoustic
Perception Channels: visual ; tactile ; acoustic ; chemical
Bornean orangutans are long lived like many of the other great ape species. They often live more than 50 years in the wild and have been documented to live up to 59 years in captivity.
Status: wild: 50 (high) years.
Status: captivity: 59 (high) years.
Status: captivity: 59.0 years.
Status: captivity: 57.3 years.
Status: wild: 59.0 years.
Status: captivity: 58.8 years.
Status: wild: 35.0 years.
Status: captivity: 50.0 years.
Lifespan, longevity, and ageing
Dominant flanged males often have an established territory that will encompass multiple females' territories. The multiple females within the male’s territory will copulate with him and produce his offspring. Younger unflanged males often cannot sustain a home range of their own and are forced to wander throughout the forests. When these small, wandering males come into contact with a female, the small unflanged male will force copulation. This is different from the flanged males which will long-call; a call to help receptive females locate him. Females prefer to mate with flanged males, which may be a way to ensure protection from unflanged males.
Mating System: polygynous
Bornean orangutans do not have a breeding season, but females show higher ovarian function during periods of food abundance. Ovulation in Bornean orangutans occurs on the 15th day of a 30-day cycle. Copulation generally occurs with both parties hanging with their arms and facing each other. Bornean orangutan's gestation period lasts about nine months after which they give birth to a single infant, although twins have been recorded. Research shows that female orangutans only breed every 6 to 8 years, and the young are nursed until age 6 and remain at the mother's side until the next birth. The offspring has contact with its mother after birth, but once female offspring start to display sexual behaviors, they begin traveling separately. Once the female offspring is separated from its mother completely, it will move off and establish a territory nearby its mother’s territory. Adolescence in Bornean orangutans starts at 5 years of age and lasts until around 8 years of age. Male offspring remain socially immature despite being sexually mature. The young males avoid contact with mature males and start to wander the forests until they become a flanged male and establish their own resident territory. Female Bornean orangutans will reach menopause around the age of 48 years.
Breeding interval: Female orangutans breed every 8 years.
Breeding season: Bornean orangutans breed year-round.
Range number of offspring: 1 to 2.
Average number of offspring: 1.
Range gestation period: 233 to 263 days.
Average gestation period: 245 days.
Range weaning age: 36 to 84 months.
Average weaning age: 42 months.
Range time to independence: 5 to 8 years.
Average time to independence: 7 years.
Range age at sexual or reproductive maturity (female): 5.8 to 11.1 years.
Range age at sexual or reproductive maturity (male): 8 to 15 years.
Key Reproductive Features: iteroparous ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous
Average birth mass: 1736.5 g.
Average number of offspring: 1.
Female Bornean orangutans invest a lot of time in their offspring, taking care of them until they reach adolescence at around 6 years of age. Since Bornean orangutans are semi-solitary in nature, the males have very little contact and no investment in their young. From birth, the offspring will be in constant contact with the mother for 4 months and will be carried everywhere the mother goes. The offspring remains completely dependent upon the mother for the first 2 years of life. At about 5 years of age, the offspring will begin to make short trips on its own, usually staying within sight of the mother. The orangutan young may start to build its own nests as play, and will eventually start sleeping in the nests it builds. The offspring are usually weaned by 4 years of age and will begin adolescence soon after. The offspring will generally stay around the mother until the next offspring are born. After this, the young females establish their own territory and the young males travel the forest until they can establish their own home territory.
Parental Investment: precocial ; female parental care ; pre-weaning/fledging (Provisioning: Female, Protecting: Female); pre-independence (Provisioning: Female, Protecting: Female); extended period of juvenile learning
Evolution and Systematics
The teeth of great apes help them survive times of food scarcity because they are diverse in type and material characteristics, allowing consumption of fallback foods.
"Lucas and colleagues recently proposed a model based on fracture and deformation concepts to describe how mammalian tooth enamel may be adapted to the mechanical demands of diet (Lucas et al.: Bioessays 30 2008 374-385). Here we review the applicability of that model by examining existing data on the food mechanical properties and enamel morphology of great apes (Pan, Pongo, and Gorilla). Particular attention is paid to whether the consumption of fallback foods is likely to play a key role in influencing great ape enamel morphology. Our results suggest that this is indeed the case. We also consider the implications of this conclusion on the evolution of the dentition of extinct hominins." (Constantino et al. 2009:653)
Learn more about this functional adaptation.
Molecular Biology and Genetics
Barcode data: Pongo pygmaeus
Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.
See the BOLD taxonomy browser for more complete information about this specimen and other sequences.
-- end --
Download FASTA File
Statistics of barcoding coverage: Pongo pygmaeus
Public Records: 3
Specimens with Barcodes: 14
Species With Barcodes: 1
Bornean orangutans are an endangered species. Since all Bornean orangutans are totally depenent on the trees for survival, forest degradation is devastating to the population. Even though the fruiting trees are not the coveted timber, the removal of trees from the area still negatively influences the overall quality of the forest. Because Bornean orangutans have to travel to find the fruiting trees, a patchy forest hinders travel and dispersal and increases competition for these limited resources.
If the Bornean orangutan is going to recover, habitat destruction must be stopped. These orangutans also need to be protected, and any harvesting for meat or for illegal pet trade must be stopped. Both of these current practices are not sustainable and may lead to the extinction of the Bornean orangutans.
US Federal List: endangered
CITES: appendix i
IUCN Red List of Threatened Species: endangered
IUCN Red List Assessment
Red List Category
Red List Criteria
- 1994Endangered(Groombridge 1994)
- 1990Endangered(IUCN 1990)
- 1988Endangered(IUCN Conservation Monitoring Centre 1988)
- 1986Endangered(IUCN Conservation Monitoring Centre 1986)
Date Listed: 06/02/1970
Lead Region: Foreign (Region 10)
Where Listed: Borneo,Sumatra
Population location: Borneo,Sumatra
Listing status: E
For most current information and documents related to the conservation status and management of Pongo pygmaeus , see its USFWS Species Profile
Follow link below for Tables 1a, b and c: population size estimates for P. p. wurmbii, P. p. pygmaeus and P. p. morio.
Major threats include:
1. Habitat losses with the destruction of vast areas of tropical forest throughout the island and their conversion to agriculture (mostly oil palm plantations - Elaeis guineensis, but also acacia, rice, subsistence crops, cocoa, etc). An overall loss of 15.5 million hectares of forest (24% of total forest area) was recorded between 1985 and 1997 in Sumatra and Kalimantan, while 37% of the total forest area was lost in Sabah between 1950 and 2000 (FAO 2000). In the lowlands (prime orangutan habitat) this figure is higher and reaches more than 60% (Holmes 2000). We consider that today only 86,000 km² of habitat remains available to the species throughout the island (which is about 740,000 km²). Protected areas home to significant orangutan populations are also threatened by habitat loss (Curran et al. 2003).
The rapid expansion of oil palm plantations in Borneo in response to international demand (the oil is used for cooking, cosmetics, mechanics, and more recently as source of bio-diesel) has accelerated habitat losses. Between 1984 and 2003, the area planted with palm oil on Borneo increased from 2,000 km² to 27,000 km²: about 10,000 km² is located in Kalimantan; 12,000 km² in Sabah and 5,000 km² in Sarawak. Many areas used to be prime habitat for the orangutans: eastern lowlands of Sabah, the plains between the Sampit and Seruyan rivers in central Kalimantan, etc.
2. Fires. The El Niño climatic event has been occurring repeatedly in the last few decades, and is associated with severe droughts and forest fires. Ninety percent of Kutai National Park was lost to massive fires in 1983 and 1998 and its orangutan population was reduced from an estimated 4000 individuals in the 1970s to a mere 500 today (Rijksen and Meijaard 1999). Over 400,000 ha of peatland forest in South Kalimantan were burnt to ashes in six months during 1997-98 following the collapse of the Mega-Rice project, representing an estimated loss of 8,000 orangutans (Page et al. 2002). Large numbers of orangutans are also killed by people while fleeing the flames and smoke during and after the fires. As a result of the 1997-98 fires, we estimate that the Bornean orangutan population was reduced by 33% in just one year. The most recent drought of 2006 in Kalimantan is thought to have killed several hundred orangutans in just six months. Forest fires can also result in the arrival of “refugees” in surrounding remnant and the resulting crowding effect can have serious negative impacts on the resident population (Husson et al. 2005).
3. Habitat exploitation and illegal logging. Although recent work in Sabah and East Kalimantan shows that orangutans can adapt and survive (at least in the short term) in commercial forest reserves exploited for timber according to sustainable logging practices (reduced-impact logging; FSC certification), it is well established that more aggressive and conventional logging practices have a negative impact on orangutan populations. Rampant legal and illegal logging results in the destruction of key food sources that sustain orangutans, and in the fragmentation of remnant subpopulations which subsequently become more prone to local extinction and catastrophes.
4. Habitat fragmentation. Recent results from the orangutan PHVA show that Bornean orangutan populations of fewer than 50 individuals are not viable in the long-term and will most probably go extinct in the next 100 years (Singleton et al. 2004, Marshall et al. in prep.). Forest fragmentation further reduces the size of orangutan populations and makes them more prone to genetic drift and inbreeding as well as to local catastrophes, such as floods, fires, outbreak diseases, hunting pressure.
5. Hunting. In some parts of the island, hunting has been a major threat and is directly responsible for local extinctions (Rijksen and Meijaard 1999). Even low levels of hunting for traditional purposes strongly reduce orangutan population densities (Marshall et al. 2006). Indeed, recent vortex models showed that a 2% hunting rate is not sustainable for this species (Singleton et al. 2004, Marshall et al. in prep.). Major reasons for hunting include: bushmeat trade, wanton killing as part of poaching for other forest products (such as gaharu or aloe wood), use of body parts for traditional medicine, pet trade and to mitigate conflicts with agriculture.
6. Pet trade. Illegal export of animals continues. In early 2004 about 100 individuals of Bornean origin were confiscated in Thailand and 50 of them were repatriated to Kalimantan in 2006. Several hundred Bornean orangutan orphans who were confiscated by local authorities have been entrusted to different orphanages in both Malaysia and Indonesia. They are in the process of being rehabilitated into the wild.
Although some major populations are found within the network of protected areas existing in Borneo, it is now well established that the vast majority of Bornean orangutans live outside protected forests. New mechanisms to ensure their long-term survival outside protected forests are urgently needed.
Relevance to Humans and Ecosystems
Bornean orangutans have the highest density in areas where there is valuable timber such as the peat swamps. In the second half of the 19th century, the Bornean orangutans lost 80% of its viable habitat. These forests are also being illegally logged, as people are logging before the 30 to 40 year rest period is over. Palm oil tree saplings are eaten after logging occurs and the orangutans are searching for another food source. The Bornean orangutans also compete with humans for durian fruit and will on rare occasions attack humans.
Negative Impacts: injures humans; crop pest
The Bornean orangutans keep the forests healthy by dispersing seeds, and eco tourism for the Bornean orangutans draws in important revenue for orangutan conservation agencies.
Positive Impacts: ecotourism
The Bornean orangutan, Pongo pygmaeus, is a species of orangutan native to the island of Borneo. Together with the Sumatran orangutan, it belongs to the only genus of great apes native to Asia. Like the other great apes, orangutans are highly intelligent, displaying advanced tool use and distinct cultural patterns in the wild. Orangutans share approximately 97% of their DNA with humans.
The Bornean orangutan is an endangered species, with deforestation, palm oil plantations and hunting posing a serious threat to its continued existence.
The Bornean orangutan and the Sumatran orangutan diverged about 400,000 years ago, with a continued low level of gene flow between them since then. The two orangutan species were considered merely subspecies until 1996; they were elevated to species following sequencing of their mitochondrial DNA.
- Northwest Bornean orangutan P. p. pygmaeus – Sarawak (Malaysia) & northern West Kalimantan (Indonesia)
- Central Bornean orangutan P. p. wurmbii – Southern West Kalimantan & Central Kalimantan (Indonesia)
- Northeast Bornean orangutan P. p. morio – East Kalimantan (Indonesia) & Sabah (Malaysia)
There is some uncertainty about this, however. The population currently listed as P. p. wurmbii may be closer to the Sumatran orangutan (P. abelii) than to the Bornean orangutan. If this is confirmed, P. abelii would be a subspecies of P. wurmbii (Tiedeman, 1808). In addition, the type locality of P. pygmaeus has not been established beyond doubt; it may be from the population currently listed as P. wurmbii (in which case P. wurmbii would be a junior synonym of P. pygmaeus, while one of the names currently considered a junior synonym of P. pygmaeus would take precedence for the taxon in Sarawak and northern West Kalimantan). Bradon-Jones et al considered P. morio to be a synonym of P. pygmaeus, and the population found in East Kalimantan and Sabah to be a potentially unnamed separate taxon.
In early October 2014, researchers from domestic and foreign countries found about 50 orangutans separate in several groups in South Kalimantan Province, although previously there are no record that the province has orangutan.
The Bornean orangutan is the third-heaviest living primate after the two species of gorilla, and the largest truly arboreal (or tree-dwelling) animal alive today. Body weights broadly overlap with the considerably taller Homo sapiens, but that species, of course, is more variable in size. The Sumatran orangutan is similar in size, but is on average marginally lighter in weight. A survey of wild orangutans found that males weigh on average 75 kg (165 lb), ranging from 50–100 kg (110–220 lb), and 1.2–1.4 m (3.9–4.6 ft) long; females average 38.5 kg (85 lb), ranging from 30–50 kg (66–110 lb), and 1–1.2 m (3.3–3.9 ft) long. While in captivity, orangutans can grow considerably overweight, up to more than 165 kg (364 lb). The heaviest known male orangutan in captivity was an obese male named "Andy", who weighed 204 kg (450 lb) in 1959 when he was 13 years old.
The Bornean orangutan has a distinctive body shape with very long arms that may reach up to 1.5 metres in length. It has a coarse, shaggy, reddish coat and prehensile, grasping hands and feet.
Habitat and distribution
The Bornean orangutan lives in tropical and subtropical moist broadleaf forests in the Bornean lowlands, as well as mountainous areas up to 1,500 metres (4,900 ft) above sea level. This species lives throughout the canopy of primary and secondary forests, and moves large distances to find trees bearing fruit.
It can be found in the two Malaysian states of Sabah and Sarawak, and three of the four Indonesian Provinces of Kalimantan. Due to habitat destruction, the species distribution is now highly patchy throughout the island; the species has become rare in the southeast of the island, as well as in the forests between the Rejang River in central Sarawak and the Padas River in western Sabah.
Behavior and ecology
In history, orangutans ranged throughout Southeast Asia and into southern China, as well as on the island of Java and in southern Sumatra. They primarily inhabit peat swamp forests, tropical health forests, and mixed dipterocarp forests.
Bornean orangutan are more solitary than their Sumatran relatives. Two or three orangutans with overlapping territories may interact, but only for short periods of time. Although orangutans are not territorial, adult males will display threatening behaviors upon meeting other males, and only socialize with females to mate. Males are considered the most solitary of the orangutans. The Bornean orangutan has a lifespan of 35–45 years in the wild; in captivity it can live to be about 60.
Despite being arboreal, the Bornean orangutan travels on the ground more than its Sumatran counterpart. This may be in part because no large terrestrial predators could threaten an orangutan in Borneo. In Sumatra, orangutans must face predation by the fierce Sumatran tiger.
The Bornean orangutan diet is composed of over 400 types of food, including wild figs, durians, leaves, seeds, bird eggs, flowers, honey, insects, and, to a lesser extent than the Sumatran orangutan, bark. They have also been known to consume the inner shoots of plants and vines. They get the necessary quantities of water from both fruit and from tree holes.
Bornean orangutans have been sighted using spears to attempt (unsuccessfully) to catch fish. The species has been observed using tools such as leaves to wipe off faeces, a pad of leaves for holding spiny durian fruit, a leafy branch for a bee swatter, a bunch of leafy branches held together as an "umbrella" while traveling in the rain, a single stick as backscratcher, and a branch or tree trunk as a missile. And in other regions, orangutans occasionally eat soil to get minerals that may neutralize the toxins and acids they consume in their primarily vegetarian diets. On rare occasions, orangutans will prey upon other, smaller primates, such as slow lorises.
Males and females generally come together only to mate. Subadult males (unflanged) will try to mate with any female and will be successful around half the time. Dominant flanged males will call and advertise their position to receptive females, who prefer mating with flanged males. Adult males will often target females with weaned infants as mating partners because the female is likely to be fertile.
Females reach sexual maturity and experience their first ovulatory cycle between about six and 11 years of age, although females with more body fat may experience this at an earlier age. The estrous cycle lasts between 22 and 30 days and menopause has been reported in captive orangutans at about age 48. Females tend to give birth at about 14–15 years of age. Newborn orangutans nurse every three to four hours, and begin to take soft food from their mothers' lips by four months. During the first year of its life, the young clings to its mother's abdomen by entwining its fingers in and gripping her fur. Offspring are weaned at about four years, but this could be much longer, and soon after they start their adolescent stage of exploring, but always within sight of their mother. During this period, they will also actively seek other young orangutans to play with and travel with.
A 2011 study on female orangutans in free-ranging rehabilitation programs found that individuals that were supplemented with food resources had shorter interbirth intervals, as well as a reduced age, at first birth.
The Bornean orangutan is more common than the Sumatran, with about 54,500 individuals in the wild, whereas only about 6,600 Sumatran orangutans are left in the wild. Orangutan are becoming increasingly endangered due to habitat destruction and the bushmeat trade, and young orangutans are captured to be sold as pets, usually entailing the killing of their mothers.
The Bornean orangutan is endangered according to the IUCN Red List of mammals, and is listed on Appendix I of CITES. The total number of Bornean orangutans is estimated to be less than 14% of what it was in the recent past (from around 10,000 years ago until the middle of the 20th century), and this sharp decline has occurred mostly over the past few decades due to human activities and development. Species distribution is now highly patchy throughout Borneo; it is apparently absent or uncommon in the southeast of the island, as well as in the forests between the Rejang River in central Sarawak and the Padas River in western Sabah (including the Sultanate of Brunei). A population of around 6,900 is found in Sabangau National Park, but this environment is at risk. According to an anthropologist at Harvard University, in 10 to 20 years, orangutans are expected to be extinct in the wild if no serious effort is made to overcome the threats they are facing.
This view is also supported by the United Nations Environment Programme, which stated in its 2007 report that due to illegal logging, fire and the extensive development of oil palm plantations, orangutans are endangered, and if the current trend continues, they will become extinct.
A November 2011 survey, based on interviews with 6,983 respondents in 687 villages across Kalimantan in 2008 to 2009, gave estimated orangutan killing rates of between 750 and 1800 in the year leading up to April 2008. These killing rates were higher than previously thought and confirm that the continued existence of the orangutan in Kalimantan is under serious threat. The survey did not quantify the additional threat to the species due to habitat loss from deforestation and expanding palm-oil plantations. The survey found that 73% of respondents knew orangutans were protected by Indonesian law.
However, the Indonesian government rarely prosecutes or punishes perpetrators. In a rare prosecution in November 2011, two men were arrested for killing at least 20 orangutans and a number of long-nosed proboscis monkeys. They were ordered to conduct the killings by the supervisor of a palm oil plantantion, to protect the crop, with a payment of $100 for a dead orangutan and $22 for a monkey.
Rescue and rehabilitation centers
A number of orangutan rescue and rehabilitation projects operate in Borneo.
The Borneo Orangutan Survival Foundation (BOS) founded by Dr Willie Smits has rescue and rehabilitation centres at Wanariset and Samboja Lestari in East Kalimantan and Nyaru Menteng, in Central Kalimantan founded and managed by Lone Drøscher Nielsen. BOS also works to conserve and recreate the fast-disappearing rainforest habitat of the orangutan, at Samboja Lestari and Mawas.
Orangutan Foundation International, founded by Dr Birutė Galdikas, rescues and rehabilitates orangutans, preparing them for release back into protected areas of the Indonesian rain forest. In addition, it promotes the preservation of the rain forest for them.
A seven-year longitudinal study published in 2011 looked at whether the lifespan of zoo-housed orangutans was related to a subjective assessment of well-being, with the intent of applying such measures to assess the welfare of orangutans in captivity. Of the subjects, 100 were Sumatran (Pongo abelii), 54 Bornean (Pongo pygmaeus) and 30 were hybrid orangutans. 113 zoo employees, who were highly familiar with the typical behavior of the orangutans, used a four-item questionnaire to assess their subjective well-being. The results indicated that orangutans in higher subjective well-being were less likely to die during the follow-up period. The study concluded that happiness was related to longer life in orangutans.
In late 2014, Nyaru Menteng veterinarians fail to rescue life of a female orangutan, although medical operation has been done to pick 40 air-riffle pellets in her body. The orangutan is found at one of palm oil plantation in Indonesian Borneo.
|NCBI genome ID|
The genome of the Bornean orangutan is programmed to be sequenced.
This article incorporates text from the ARKive fact-file "Bornean orangutan" under the Creative Commons Attribution-ShareAlike 3.0 Unported License and the GFDL.
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