page_title: Orangutan
section_title: Social life
hierarchical_section_title: Orangutan / Ecology and behaviour / Social life
caption_attribution_description: English: wild orang utans, Gunung Leuser NP, Sumatra
context_page_description: Orangutans are great apes native to Indonesia and Malaysia. They are found in the rainforests of Borneo and Sumatra, but during the Pleistocene they ranged throughout Southeast Asia and South China. Classified in the genus Pongo, orangutans were originally considered to be one species. From 1996, they were divided into two species: the Bornean orangutan and the Sumatran orangutan. In 2017, a third species, the Tapanuli orangutan, was identified. The orangutans are the only surviving species of the subfamily Ponginae, who split from humans, chimpanzees and gorillas 19.3 to 15.7 million years ago.
  The most arboreal of the great apes, orangutans spend most of their time in trees. They have proportionally long arms and short legs and their hair is reddish-brown. Adult males may develop distinctive cheek pads or flanges and make long calls that attract females and intimidate rivals; younger males do not and resemble adult females. Orangutans are the most solitary of the great apes, social bonds occurring primarily between mothers and their dependent offspring, who remain together for the first two years.
context_section_description: The social structure of the orangutan can be best described as solitary but social; they live a more solitary lifestyle than the other great apes. Bornean orangutans are generally more solitary than Sumatran orangutans. 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. Interactions between adult females range from friendly to avoidance to antagonistic. The home ranges of resident males can overlap greatly, though encounters are relatively rare and hostile. Adult males are dominant over sub-adult males, the latter of which keep their distance.
  Orangutans disperse and establish their home ranges by age 11. Females tend to settle close to their mothers, while males disperse much farther but may include their natal (birth) range within their new 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. They are often consortships between an adult male and a female. Social grooming is uncommon among orangutans.
  Orangutans communicate with various sounds. Males will make long calls, both to attract females and to advertise themselves to other males. These are divided into three parts; they begin with grumbles, climax with pulses and end with bubbles. Both sexes will try to intimidate conspecifics with a series of low guttural noises known collectively as the "rolling call". When annoyed, an orangutan will suck in air through pursed lips, making a kissing sound known as the "kiss squeak". Mothers produce throatscrapes to keep in contact with their offspring. Infants make soft hoots when distressed. Orangutans are also known to produce smacks or blow raspberries when making a nest.
caption: Orangutans are the least social of the great apes.
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