The orangutans are the only surviving species of the subfamily Ponginae, which diverged genetically from the other hominids (gorillas, chimpanzees, and humans) between 19.3 and 15.7 million years ago.

Threats to wild orangutan populations include poaching (for bushmeat and retaliation for consuming crops), habitat destruction and deforestation (for palm oil cultivation and logging), and the illegal pet trade.

[3]) In Western sources, the first printed attestation of the word for the apes is in Dutch physician Jacobus Bontius' 1631 Historiae naturalis et medicae Indiae orientalis.

[14][8]: 24–25  Battel's "Pongo", in turn, is from the Kongo word mpongi[15][16] or other cognates from the region: Lumbu pungu, Vili mpungu, or Yombi yimpungu.

[18] In 2001, P. abelii was confirmed as a full species based on molecular evidence published in 1996,[19][20]: 53 [21] and three distinct populations on Borneo were elevated to subspecies (P. p. pygmaeus, P. p. morio and P. p.

Israfil and colleagues (2011) estimated based on mitochondrial, Y-linked, and X-linked loci that the Sumatran and Bornean species diverged 4.9 to 2.9 mya.[26]: Fig.

Millions of years ago, orangutans travelled from mainland Asia to Sumatra and then Borneo as the islands were connected by land bridges during the recent glacial periods when sea levels were much lower.

[38] Females and juveniles have relatively circular skulls and thin faces while mature males have a prominent sagittal crest, large cheek pads or flanges,[35] extensive throat pouches and long canines.

[40] Orangutan hands have four long fingers but a dramatically shorter opposable thumb for a strong grip on branches as they travel high in the trees.

[62] 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.

[40][20]: 100 Unflanged males wander widely in search of oestrous females and upon finding one, may force copulation on her, the occurrence of which is unusually high among mammals.

[83] Orangutans can learn to mimic new sounds by purposely controlling the vibrations of their vocal folds, a trait that led to speech in humans.

[93] Primatologist Carel P. van Schaik and biological anthropologist Cheryl D. Knott further investigated tool use in different wild orangutan populations.

[98] 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.

[99] 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".

[101][102] 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".

[107] 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.

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.

[8]: 108–09 Thomas Love Peacock's 1817 novel Melincourt features Sir Oran Haut Ton, an orangutan who lives among English people and becomes a candidate for Member of Parliament.

[8]: 110–11  In Frank Challice Constable's The Curse of Intellect (1895), the protagonist Reuben Power travels to Borneo and captures an orangutan to train it to speak so he can "know what a beast like that might think of us".

[8]: 114–15  Orangutans are featured prominently in the 1963 science fiction novel Planet of the Apes by Pierre Boulle and the media franchise derived from it.

[8]: 118–19, 175–76 Orangutans are sometimes portrayed as antagonists, notably in the 1832 Walter Scott novel Count Robert of Paris and the 1841 Edgar Allan Poe short story The Murders in the Rue Morgue.

[8]: 145  Disney's 1967 animated musical adaptation of The Jungle Book added a jazzy orangutan named King Louie, who tries to get Mowgli to teach him how to make fire.

[8]: 266  The 1986 horror film Link features an intelligent orangutan which serves a university professor but has sinister motives; he plots against humanity and stalks a female student assistant.

[110][111] 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.

He was nicknamed "the hairy Houdini" and was the subject of a fan club, T-shirts, bumper stickers and a song titled The Ballad of Ken Allen.

[116] 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.

[118][119][120] They are legally protected from capture, harm or killing in both Malaysia and Indonesia,[121] and are listed under Appendix I by CITES, which prohibits their unlicensed trade under international law.

[118][119] Orangutans may be killed for the bushmeat trade[125] and bones are secretly sold in souvenir shops in several cities in Indonesian Borneo.