[3] 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.

Its original name was Simia satyrus, meaning "satyr monkey", but was changed when scientists discovered that not all orangutans are one species.

It has grey skin, a coarse, shaggy, reddish coat[17] and prehensile, grasping hands and feet.

[19] Bornean orangutans are highly sexually dimorphic and have several features that differ between males and females.

Males have much larger cheek pads, or flanges, that are composed of muscle and large amounts of fat.

[20] This species lives throughout the canopy of primary and secondary forest, and moves large distances to find trees bearing fruit.

[1] The first complete orangutan skeleton that was discovered was in the Hoa Binh province in Vietnam and thought to be from the late Pleistocene epoch.

Additional features such as shade, waterproof roof, "pillow", and "blanket", all of which are made from branches, twigs and leaves, may also be added.

[28] The Bornean orangutan diet is composed of over 400 types of food, including wild figs, durians (Durio zibethinus and D. graveolens),[29] leaves, seeds, bird eggs, flowers, sap, vines,[30] honey, fungi, spider webs,[30] insects, and, to a lesser extent than the Sumatran orangutan, bark.

[32] In some regions, orangutans occasionally eat soil to get minerals that may neutralize the toxins and acids they consume in their primarily vegetarian diets.

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 hair.

The birth rate for orangutans has been decreasing largely due to a lack of sufficient nutrients as a result of habitat loss.

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.

[38] 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 palm oil plantations, orangutans are critically endangered, and if the current trend continues, they will become extinct.

It is in high demand because it is used in several packaged foods, deodorants, shampoos, soaps, candies, and baked goods.

The effects that human activity have had on Indonesian rainfall have made food less abundant and so Bornean orangutans are less likely to receive full nutrients so that they can be sufficiently healthy to breed.

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.

[41] 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.

[42] 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 plantation, to protect the crop, with a payment of $100 for a dead orangutan and $22 for a monkey.

The Borneo Orangutan Survival Foundation (BOS) founded by 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.

[44] Orangutan Foundation, founded by Ashley Leiman, operates programmes in Central Kalimantan, Indonesian Borneo.

The Foundation rescues orphaned orangutans and enters them into their soft-release programme, allowing them to develop the skills necessary to survive in the wild.

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.

[48] During this time, this event's dry climate during the Late Pleistocene attributed to a more abundant genetic exchange.

[49] Therefore, natural geographic barriers are attributed to be the reason as to why the Bornean orangutans were eventually isolated and ended up colonizing other regions.

[48] This article incorporates text from the ARKive fact-file "Bornean orangutan" under the Creative Commons Attribution-ShareAlike 3.0 Unported License and the GFDL.