Orangutan

Most Western sources attribute the name "orangutan" (also written orang-utan, orang utan, orangutang, and ourang-outang) to the Malay words , meaning 'person', and , meaning 'forest'. The Malay used the term to indicate forest-dwelling humans; the first recorded Malay use of "" referring to the ape identifies it as a Western term. The word appeared in several German-language descriptions of Indonesian zoology in the 17th century. It has been argued that the word comes specifically from the Banjarese variety of Malay, but the age of the Old Javanese sources mentioned above makes Old Malay a more likely origin for the term. Cribb and colleagues (2014) suggest that Bontius's account referred not to apes (as this description was from Java where the apes were not known to be from) but to humans suffering some serious medical condition (most likely cretinism) and that his use of the word was misunderstood by Nicolaes Tulp, who was the first to use the term in a publication a decade later. The word was first attested in English in 1693 by physician John Bulwer in the form Orang-Outang, and variants ending with -ng are found in many languages. This spelling (and pronunciation) has remained in use in English up to the present but has come to be regarded as incorrect. The loss of "h" in and the shift from -ng to -n has been taken to suggest the term entered English through Portuguese. or other cognates from the region: Lumbu , Vili mpungu, or Yombi yimpungu. == Taxonomy and phylogeny ==

The orangutan was first described scientifically in 1758 in the Systema Naturae of Carl Linnaeus as Homo troglodytes. In 2001, P. abelii was confirmed as a full species based on molecular evidence published in 1996, The description in 2017 of a third species, P. tapanuliensis, from Sumatra south of Lake Toba, came with a surprising twist: it is more closely related to the Bornean species, P. pygmaeus than to its fellow Sumatran species, P. abelii. , Sumatran and Tapanuli orangutans The Sumatran orangutan genome was sequenced in January 2011. Following humans and chimpanzees, the Sumatran orangutan became the third species of great ape whose genome was sequenced. Subsequently, the Bornean species's genome was sequenced. Bornean orangutans (P. pygmaeus) exhibit less genetic diversity than Sumatran orangutans (P. abelii), despite the latter's population being six to seven times greater. The researchers hope these genetic data may help conservationists preserve the endangered ape, as well as learn more about human genetic diseases. By contrast, the 2011 genome study suggested that these two species diverged as recently as circa 400,000 years ago. The study also found that orangutans evolved at a slower pace than both chimpanzees and humans. Fossil record The three orangutan species are the only extant members of the subfamily Ponginae. This subfamily also includes extinct apes such as Lufengpithecus, which occurred 8–2 mya in southern China and Thailand; These animals likely lived in drier and cooler environments than orangutans do today. Khoratpithecus piriyai, which lived 5–7 mya in Thailand, is believed to be the closest known relative of the living orangutans and inhabited similar environments. Pongo is found as part of the faunal complex in the Pleistocene cave assemblage in Vietnam, alongside Giganopithecus, though it is known only from teeth. Some fossils described under the name P. hooijeri have been found in Vietnam, and multiple fossil subspecies have been described from several parts of southeastern Asia. It is unclear if these belong to P. pygmaeus or P. abelii or, in fact, represent distinct species. In 2025, two other distinct species from Pleistocene deposists in the Làng Tráng and Kéo Lèng caves in Vietnam were described as P. grovesei and P. nguyenbinheri. During the Pleistocene, Pongo had a far more extensive range than at present, extending throughout Sundaland and mainland Southeast Asia and South China. Teeth of orangutans are known from Peninsular Malaysia that date to 60,000 years ago. The range of orangutans had contracted significantly by the end of the Pleistocene, most likely because of the reduction of forest habitat during the Last Glacial Maximum. They may have nevertheless survived into the Holocene in Cambodia and Vietnam. == Characteristics ==

Orangutans display significant sexual dimorphism; females typically stand tall and weigh around , while adult males stand tall and weigh . The tallest orangutan recorded was a . Compared to humans, they have proportionally long arms, a male orangutan having an arm span of about , and short legs. They are covered in long reddish hair that starts out bright orange and darkens to maroon or chocolate with age, while the skin is grey-black. Though largely hairless, males' faces can develop some hair, giving them a beard. Orangutans have small ears and noses; the ears are unlobed. The cranium is elevated relative to the face, which is incurved and prognathous. Females and juveniles have relatively circular skulls and thin faces while mature males have a prominent sagittal crest, large cheek pads or flanges, The throat pouches act as resonance chambers for making long calls. Their feet have four long toes and an opposable big toe, giving them hand-like dexterity. The hip joints also allow for their legs to rotate similarly to their arms and shoulders. Compared to their relatives in Borneo, Sumatran orangutans are more slender with paler and longer hair and a longer face. Tapanuli orangutans resemble Sumatran orangutans more than Bornean orangutans in body build and hair colour. They have shaggier hair, smaller skulls, and flatter faces than the other two species. == Ecology and behaviour ==

, Malaysia, Borneo island) Orangutans are mainly arboreal and inhabit tropical rainforest, particularly lowland dipterocarp and old secondary forest. Orangutans occasionally enter grasslands, cultivated fields, gardens, young secondary forest, and shallow lakes. They start the day feeding for two to three hours in the morning. They rest during midday, then travel in the late afternoon. When evening arrives, they prepare their nests for the night. Orangutans also use the plant species Dracaena cantleyi as an anti-inflammatory balm. Captive animals may suffer an upper respiratory tract disease. Diet and feeding Orangutans are primarily fruit-eaters, which can take up 57–80% of their foraging time. Even during times of scarcity, fruit is 16% of their feeding time. Fruits with soft pulp, arils or seed-walls are consumed the most, particularly figs but also drupes and berries. Orangutans also include leaves in their diet, which take up 25% of their average foraging time. Leaves are eaten more when fruit is less available, but even during times of fruit abundance, orangutans will eat leaves 11–20% of the time. They appear to depend on the leaf and stem material of Borassodendron borneensis during times of low fruit abundance. Other food items consumed by the apes include bark, honey, bird eggs, insects and small vertebrates including slow lorises. Most social bonds occur between adult females and their dependent and weaned offspring. Resident females live with their offspring in defined home ranges that overlap with those of other adult females, which may be their immediate relatives. One to several resident female home ranges are encompassed within the home range of a resident male, who is their main mating partner. Flanged males are often hostile to both other flanged males and unflanged males, while unflanged males are more peaceful towards each other. Orangutans disperse and establish their home ranges by age 11. Females tend to live near their birth range, while males disperse farther but may still visit their birth range within their larger home range. They enter a transient phase, which lasts until a male can challenge and displace a dominant, resident male from his home range. Both resident and transient orangutans aggregate on large fruiting trees to feed. The fruits tend to be abundant, so competition is low and individuals may engage in social interactions. Orangutans will also form travelling groups with members moving between different food sources. Social grooming is uncommon among orangutans. Orangutan calls display consonant- and vowel-like components and they maintain their meaning over great distances. They also display recursion via three layers of rhythmic sounds. Mother orangutans and offspring also use several different gestures and expressions such as beckoning, stomping, lower lip pushing, object shaking and "presenting" a body part. These communicate goals such as "acquire object", "climb on me", "climb on you", "climb over", "move away", "play change: decrease intensity", "resume play" and "stop that". Reproduction and development Males become sexually mature at around age 15. They may exhibit arrested development by not developing the distinctive cheek pads, pronounced throat pouches, long fur, or long calls until a resident dominant male is absent. The transformation from unflanged to flanged can occur quickly. Flanged males attract females in oestrous with their characteristic long calls, which may also suppress development in younger males. Non-ovulating females do not usually resist copulation with unflanged males, as the chance of conception is low. Unlike females of other non-human great ape species, orangutans do not exhibit sexual swellings to signal fertility. Gestation is around nine months long and infants are born at a weight of . Unlike many other primates, male orangutans do not seem to practise infanticide. This may be because they cannot ensure they will sire a female's next offspring, because she does not immediately begin ovulating again after her infant dies. There is evidence that females with offspring under six years old generally avoid adult males. Females do most of the caring of the young. The mother will carry the infant while travelling, suckle it and sleep with it. After two years of age, juvenile orangutans will begin to move away from their mothers temporarily. They reach adolescence at six or seven years of age and are able to live alone but retain some connections with their mothers. Typically, orangutans live over 30 years both in the wild and in captivity. Construction of a night nest is done by following a sequence of steps. Initially, a suitable tree is located. Orangutans are choosy about sites, though nests can be found in many tree species. To establish a foundation, the ape grabs the large branches under it and bends them so they join. The orangutan then does the same to smaller, leafier branches to create a "mattress". After this, the ape stands and braids the tips of branches into the mattress. Doing this increases the stability of the nest. Orangutans make their nests more comfortable by creating "pillows", "blankets", "roofs" and "bunk-beds". == Intelligence ==

has a touch-screen computer on which their two Sumatran orangutans play games. A 2008 study of two orangutans at the Leipzig Zoo showed orangutans may practise "calculated reciprocity", which involves an individual aiding another with the expectation of being paid back. Orangutans are the first nonhuman species documented to do so. In a 1997 study, two captive adult orangutans were tested with the cooperative pulling paradigm. Without any training, the orangutans succeeded in pulling off an object to get food in the first session. Over the course of 30 sessions, the apes succeeded more quickly, having learned to coordinate. An adult orangutan has been documented to pass the mirror test, indicating self-awareness, while another test with a 2-year-old failed to reveal self-recognition. Studies in the wild indicate that flanged male orangutans plan their movements in advance and signal them to other individuals. Experiments have also suggested that orangutans can communicate about things that are not present: mother orangutans remain silent in the presence of a perceived threat but when it passes, the mother produces an alarm call to their offspring to teach them about the danger. Orangutans and other great apes show laughter-like vocalisations in response to physical contact such as wrestling, play chasing or tickling. This suggests that laughter derived from a common origin among primate species and therefore evolved before the origin of humans. Orangutans can learn to mimic new sounds by purposely controlling the vibrations of their vocal folds, a trait that led to speech in humans. Bonnie, an orangutan at the US National Zoo, was recorded spontaneously whistling after hearing a caretaker. She appears to whistle without expecting a food reward. Tool use and culture using a tool to extract orange-juice concentrate|alt=An orangutan using a stick to pick at a hole in a rock with a cup of orange-juice concentrate. Tool use in orangutans was observed by primatologist Biruté Galdikas in ex-captive populations. Orangutans in Suaq Balimbing were recorded to develop a tool kit for use in foraging which consisted of both insect-extraction sticks for use in the hollows of trees and seed-extraction sticks for harvesting seeds from hard-husked fruit. The orangutans adjusted their tools according to the task at hand, and preference was given to oral tool use. This preference was also found in an experimental study of captive orangutans. Orangutans have been observed to use sticks to poke at catfish, causing them to leap out of the water so the orangutan can grab them. Orangutan have also been documented to keep tools for later. When building a nest, orangutans appear to be able to determine which branches would better support their body weight. Primatologist Carel P. van Schaik and biological anthropologist Cheryl D. Knott further investigated tool use in different wild orangutan populations. They compared geographic variations in tool use related to the processing of Neesia fruit. The orangutans of Suaq Balimbing were found to be avid users of insect and seed-extraction tools when compared to other wild orangutans. The scientists suggested these differences are cultural as they do not correlate with habitat. The orangutans at Suaq Balimbing are closely spaced and relatively tolerant of each other; this creates favourable conditions for the spreading of new behaviours. Wild orangutans in Tuanan, Borneo, were reported to use tools in acoustic communication. They use leaves to amplify the kiss squeak sounds they produce. The apes may employ this method of amplification to deceive the listener into believing they are larger animals. In 2003, researchers from six different orangutan field sites who used the same behavioural coding scheme compared the behaviours of the animals from each site. They found each orangutan population used different tools. The evidence suggested the differences were cultural: first, the extent of the differences increased with distance, suggesting cultural diffusion was occurring, and second, the size of the orangutans' cultural repertoire increased according to the amount of social contact present within the group. Social contact facilitates cultural transmission. During a field observation in 2022, a male Sumatran orangutan, known to researchers as Rakus, chewed Fibraurea tinctoria vine leaves and applied the mashed plant material to an open wound on his face. According to primatologists who had been observing Rakus at a nature preserve, "Five days later the facial wound was closed, while within a few weeks it had healed, leaving only a small scar". Personhood In June 2008, Spain would become the first country to recognise the rights of some non-human great apes, based on the guidelines of the Great Ape Project, which are that chimpanzees, bonobos, orangutans, and gorillas are not to be used for animal experiments. In December 2014, a court in Argentina ruled that an orangutan named Sandra at the Buenos Aires Zoo must be moved to a sanctuary in Brazil to provide her "partial or controlled freedom". Animal rights groups like Great Ape Project Argentina argued the ruling should apply to all species in captivity, and legal specialists from the Argentina's Federal Chamber of Criminal Cassatio considered the ruling applicable only to non-human hominids. == Orangutans and humans ==

presenting her book about the apes Orangutans were known to the native people of Sumatra and Borneo for millennia. The apes are known as maias in Sarawak and mawas in other parts of Borneo and in Sumatra. While some communities hunted them for food and decoration, others placed taboos on such practices. In central Borneo, some traditional folk beliefs consider it bad luck to look an orangutan in the face. Some folk tales involve orangutans mating with and kidnapping humans. There are even stories of hunters being captured by female orangutans. Little was known about orangutan behaviour until the field studies of Biruté Galdikas, who became a leading authority on the apes. When she arrived in Borneo in 1971, Galdikas settled into a primitive bark-and-thatch hut at a site she dubbed Camp Leakey, in Tanjung Puting. She studied orangutans for the next four years and developed her PhD thesis for UCLA. Galdikas became an outspoken advocate for orangutans and the preservation of their rainforest habitat, which is rapidly being devastated by loggers, palm oil plantations, gold miners, and unnatural forest fires. Along with Jane Goodall and Dian Fossey, Galdikas is considered to be one of Leakey's Angels, named after anthropologist Louis Leakey. In fiction " by Daniel Vierge Orangutans first appeared in Western fiction in the 18th century and have been used to comment on human society. Written by the pseudonymous A. Ardra, Tintinnabulum naturae (The Bell of Nature, 1772) is told from the point of view of a human-orangutan hybrid who calls himself the "metaphysician of the woods". Around 50 years later, the anonymously written work The Orang Outang is narrated by a pure orangutan in captivity in the US, writing a letter critiquing Boston society to her friend in Java. Zoos and circuses in the Western world would continue to use orangutans and other simians as sources for entertainment, training them to behave like humans at tea parties and to perform tricks. Notable orangutan "character actors" include: Jacob and Rosa of the Tierpark Hagenbeck in Hamburg, Germany, in the early 20th century; Joe Martin of Universal City Zoo in the 1910s and 1920s; and Jiggs of the San Diego Zoo in the 1930s and 1940s. Animal rights groups have urged a stop to such acts, considering them abusive. Starting in the 1960s, zoos became more concerned with education and orangutans' exhibits were designed to mimic their natural environment and let them display their natural behaviours. Galdikas reported that her cook was sexually assaulted by a captive male orangutan. The ape may have suffered from a skewed species identity and forced copulation is a standard mating strategy for low-ranking male orangutans. American animal trafficker Frank Buck claimed to have seen human mothers acting as wet nurses to orphaned orangutan babies in hopes of keeping them alive long enough to sell to a trader, which would be an instance of human–animal breastfeeding. == Conservation ==

Status and threats All three species are critically endangered according to the IUCN Red List of mammals. They are legally protected from capture, harm or killing in both Malaysia and Indonesia, and are listed under Appendix I by CITES, which prohibits their unlicensed trade under international law. The Bornean orangutan range has become more fragmented, with few or no apes documented in the southeast. The Sumatran orangutan is found only in the northern part of Sumatra, most of the population inhabiting the Leuser Ecosystem. By the 2000s, orangutan habitats decreased rapidly because of logging, mining and fragmentation by roads. A major factor has been the conversion of vast areas of tropical forest to palm oil plantations in response to international demand. Hunting is also a major problem, as is the illegal pet trade. and bones are secretly sold in souvenir shops in several cities in Indonesian Borneo. Conflicts between locals and orangutans also pose a threat. Orangutans that have lost their homes often raid agricultural areas and end up being killed by villagers. Locals may also be motivated to kill orangutans for food or because of their perceived danger. Mother orangutans are killed so their infants can be sold as pets. Between 2012 and 2017, the Indonesian authorities, with the aid of the Orangutan Information Center, seized 114 orangutans, 39 of which were pets. Estimates in the 2000s found that around 6,500 Sumatran orangutans and around 54,000 Bornean orangutans remain in the wild. A 2016 study estimates a population of 14,613 Sumatran orangutans in the wild, twice that of previous population estimates, while 2016 estimates suggest 104,700 Bornean orangutans exist in the wild. Fewer than 800 Tapanuli orangutans are estimated to still exist, which puts the species among the most endangered of the great apes. Conservation centres and organisations , Indonesia. Several organisations are working for the rescue, rehabilitation and reintroduction of orangutans. The largest of these is the Borneo Orangutan Survival (BOS) Foundation, founded by conservationist Willie Smits and which operates projects such as the Nyaru Menteng Rehabilitation Program founded by conservationist Lone Drøscher Nielsen. A female orangutan was rescued from a village brothel in Kareng Pangi village, Central Kalimantan, in 2003. The orangutan was shaved and chained for sexual purposes. Since being freed, the orangutan, named Pony, has been living with the BOS. She has been re-socialised to live with other orangutans. In May 2017, the BOS rescued an albino orangutan from captivity in a remote village in Kapuas Hulu, on the island of Kalimantan in Indonesian Borneo. According to volunteers at BOS, albino orangutans are extremely rare (one in ten thousand). This is the first albino orangutan the organisation has seen in 25 years of activity. Other major conservation centres in Indonesia include those at Tanjung Puting National Park, Sebangau National Park, Gunung Palung National Park and Bukit Baka Bukit Raya National Park in Borneo and the Gunung Leuser National Park and Bukit Lawang in Sumatra. In Malaysia, conservation areas include Semenggoh Wildlife Centre and Matang Wildlife Centre also in Sarawak, and the Sepilok Orangutan Rehabilitation Centre in Sabah. Major conservation centres headquartered outside the orangutans' home countries include Frankfurt Zoological Society, Orangutan Foundation International, which was founded by Galdikas, and the Australian Orangutan Project. Conservation organisations such as the Orangutan Land Trust work with the palm oil industry to improve sustainability and encourages the industry to establish conservation areas for orangutans. == See also ==