Bornean orangutan

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Bornean orangutan
Dublin zoo Orangutang 2011.jpg
Male at Dublin Zoo
Bornean Orangutan mother and baby, Seneca Park Zoo.JPG
Female with infant at the Seneca Park Zoo
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Primates
Suborder: Haplorhini
Infraorder: Simiiformes
Family: Hominidae
Genus: Pongo
Species: P. pygmaeus
Binomial name
Pongo pygmaeus
(Linnaeus, 1760)
Subspecies
  • Pongo pygmaeus morio
  • Pongo pygmaeus pygmaeus
  • Pongo pygmaeus wurmbii
Mapa distribuicao pongo pygmaeus.png
Distribution of Pongo pygmaeus in Borneo
Synonyms

P. agris (Schreber, 1799)
P. batangtuensis (Selenka, 1896)
P. borneensis Röhrer-Ertl, 1983
P. borneo (Lacépède, 1799)
P. brookei (Blyth, 1853)
P. curtus (Blyth, 1855)
P. dadappensis (Selenka, 1896)
P. genepaiensis (Selenka, 1896)
P. landakkensis (Selenka, 1896)
P. morio (Owen, 1837)
P. owenii (Blyth, 1853)
P. rantaiensis (Selenka, 1896)
P. rufus (Lesson, 1840)
P. satyrus (Linnaeus, 1766) [in part]
P. skalauensis (Selenka, 1896)
P. sumatranus (Mayer, 1856)
P. tuakensis (Selenka, 1896)
P. wallichii (Gray, 1871)
P. wurmbii (Tiedemann, 1808)

The Bornean orangutan (Pongo pygmaeus) is a species of orangutan native to the island of Borneo. Together with the Sumatran orangutan and Tapanuli orangutan, it belongs to the only genus of great apes native to Asia. Like the other great apes, orangutans are highly intelligent, displaying tool use and distinct cultural patterns in the wild. Orangutans share approximately 97% of their DNA with humans.[2]

The Bornean orangutan is a critically endangered species, with deforestation, palm oil plantations and hunting posing a serious threat to its continued existence.

Taxonomy[edit]

The Bornean orangutan and the Sumatran orangutan diverged about 400,000 years ago,[3] with a continued low level of gene flow between them since then.[3] The two orangutan species were considered merely subspecies until 1996; they were elevated to species following sequencing of their mitochondrial DNA.

The Bornean orangutan has three subspecies:[4][5]

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).[6] 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).[6] 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.[6]

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 is no record that the province has orangutans.[7]

As a member of the family Hominidae, Bornean orangutans are one of the closest extant relatives to Homo sapiens.

This species was originally discovered by native Malaysians. There are several mentions of orangutans in Malaysian folklore. However, this species was originally named and described by notable zoologist Carl Linneus in 1799. Its original name was Simia satyrus meaning "satyr monkey" but was changed when scientists discovered that not all orangutans are one species. The holotype of this organism is located in the British Museum in London.[8]

The current species name P. pygmaeus is not Latin unlike most other Linnean classifications. The genus name Pongo is derived from the Bantu word mpongo used to indicate a large primate. It was originally used to describe chimpanzees in Western African dialects.[9] The species name pygmaeus is derived from the Greek word "pygmy" meaning dwarf.[10]

Physical description[edit]

The skull
The skeleton

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.[11] Body weights broadly overlap with the considerably taller Homo sapiens, but the latter is considerably more variable in size.[12] By comparison, the Sumatran orangutan is similar in size but, on average, is marginally lighter in weight.[13][14] 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.[15][16] While in captivity, orangutans can grow considerably overweight, up to more than 165 kg (364 lb).[17] 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.[18]

The Bornean orangutan has a distinctive body shape with very long arms that may reach up to 1.5 metres in length. It has grey skin, a coarse, shaggy, reddish coat[19] and prehensile, grasping hands and feet.[20] Its coat does not cover its face unlike most mammals, although Bornean orangutans do have some hair on their faces including a beard and mustache. It also has large, fatty cheek pads known as flanges as well as a pendulous throat sac.[21]

A male orangutan at Moscow Zoo. The male's face pad widens as he grows older.

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. In females, the flanges are mostly composed of muscle. Males have relatively larger canines and premolars. Males have a more pronounced beard and mustache. The throat sac in males is also considerably larger. There are two body types for sexually mature males: smaller or larger. Larger males are more dominant but smaller males still breed successfully. There is little sexual dimorphism at birth.[21]

Habitat and distribution[edit]

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.[22] This species lives throughout the canopy of primary and secondary forests, and moves large distances to find trees bearing fruit.[22]

It can be found in the two Malaysian states of Sabah and Sarawak, and three of the four Indonesian Provinces of Kalimantan.[4] 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 Rajang River in central Sarawak and the Padas River in western Sabah.[4]

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. It differed from modern orangutans only in that its body was proportionately smaller compared to its head. This fossil and others confirm that orangutans once inhabited continental Southeast Asia even though currently, Bornean orangutans are only found in Malaysia.[23]

Behavior and ecology[edit]

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 heath forests, and mixed dipterocarp forests.[2]

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.[24] Although orangutans are not territorial, adult males will display threatening behaviors upon meeting other males, and only socialize with females to mate.[25] Males are considered the most solitary of the orangutans. The Bornean orangutan has a lifespan of 35–45 years in the wild;[3] in captivity it can live to be about 60.[26]

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.[27]

Diet[edit]

The Bornean orangutan diet is composed of over 400 types of food, including wild figs, durians (Durio zibethinus and D. graveolens),[28] leaves, seeds, bird eggs, flowers, honey, insects, and, to a lesser extent than the Sumatran orangutan, bark.[2][16] They have also been known to consume the inner shoots of plants and vines.[2] They get the necessary quantities of water from both fruit and from tree holes.[22]

A orangutan peeling a banana with its foot.

Bornean orangutans have been sighted using spears to attempt (unsuccessfully) to catch fish.[29] 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.[30] 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.[2] On rare occasions, orangutans will prey upon other, smaller primates, such as slow lorises.[2]

Reproduction[edit]

A rehabilitated female with her young baby in Sepilok Orang Utan Rehabilitation Centre, Sabah, Malaysia

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.[24] Dominant flanged males will call and advertise their position to receptive females, who prefer mating with flanged males.[24] Adult males will often target females with weaned infants as mating partners because the female is likely to be fertile.[31]

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.[24] The estrous cycle lasts between 22 and 30 days and menopause has been reported in captive orangutans at about age 48.[24] 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.[24] During this period, they will also actively seek other young orangutans to play with and travel with. On average, juveniles do not become completely independent until they are about seven years of age. The birth rate for orangutans has been decreasing largely due to a lack of sufficient nutrients as a result of loss of habitat.

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.[32]

Conservation status[edit]

The Bornean orangutan is more common than the Sumatran, with about 54,500 individuals in the wild, whereas about 15,000 Sumatran orangutans are left in the wild.[citation needed] Orangutans 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.[33]

The Bornean orangutan is critically endangered[4][34] 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.[4] 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 Rajang River in central Sarawak and the Padas River in western Sabah (including the Sultanate of Brunei).[4] A population of around 6,900 is found in Sabangau National Park, but this environment is at risk.[35] 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.[36]

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.[37] When forests are burned down to clear room for palm oil plantations, not only does the Bornean orangutan suffer from habitat loss, but several individuals have been burned and killed in fires. Palm oil is accounts for over one tenth of Indonesia's export earnings. It is in high demand because it is used in several packaged foods, deodorants, shampoos, soaps, candies, and baked goods.[38]

Climate change is another threat to Bornean orangutan conservation. The affects 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.[39] 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.[39]

However, the Indonesian government rarely prosecutes or punishes perpetrators.[40] 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.[41]

A young captive orangutan sleeping.

Rescue and rehabilitation centers[edit]

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.

The Sepilok Orang Utan Rehabilitation Centre near Sandakan in the state of Sabah in Malaysian Borneo opened in 1964 as the first official orangutan rehabilitation project.[42]

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.[43]

Humans can protect Bornean orangutans by supporting political efforts against orangutan hunting, against climate change, and using products that do not contain palm oil.

In late 2014, Nyaru Menteng veterinarians failed to rescue the life of a female orangutan. An operation was performed in which 40 air-rifle pellets were removed from her body. The orangutan was found at a palm oil plantation in Indonesian Borneo.[44]

Genome[edit]

Genomic information
NCBI genome ID 10714

The genome of the Bornean orangutan is programmed to be sequenced.

See also[edit]

References[edit]

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

  1. ^ Ancrenaz, Mark; Gumal, M.; Marshall, Andrew; Meijaard, Erik; Wich, Serge A.; Hussons, Steve J. (2016). "Pongo pygmaeus". IUCN Red List of Threatened Species. 2016.1. International Union for Conservation of Nature: e.T17975A17966347. doi:10.2305/IUCN.UK.2016-1.RLTS.T17975A17966347.en. Retrieved 5 September 2016. 
  2. ^ a b c d e f "Orangutan Facts". Orangutan Foundation International. Retrieved 2012-03-17. 
  3. ^ a b c Locke, Devin P.; et al. (2011-01-26). "Comparative and demographic analysis of orang-utan genomes". Nature. 469 (7331): 529–533. Bibcode:2011Natur.469..529L. doi:10.1038/nature09687. PMC 3060778 Freely accessible. PMID 21270892. Retrieved 2011-04-09. 
  4. ^ a b c d e f Ancrenaz, M.; Marshall, A.; Goossens, B.; van Schaik, C.; Sugardjito, J.; Gumal, M.; Wich, S. (2008). "Pongo pygmaeus". IUCN Red List of Threatened Species. International Union for Conservation of Nature. 2008: e.T17975A7640635. doi:10.2305/IUCN.UK.2008.RLTS.T17975A7640635.en. 
  5. ^ Groves, C.P. (2005). Wilson, D.E.; Reeder, D.M., eds. Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Baltimore: Johns Hopkins University Press. pp. 183–184. ISBN 0-801-88221-4. OCLC 62265494. 
  6. ^ a b c Bradon-Jones, D.; Eudey, A.A.; Geissmann, T.; Groves, C.P.; Melnick, D.J.; Morales, J.C.; Shekelle, M.; Stewart, C.B. (2004). "Asian primate classification" (PDF). International Journal of Primatology. 25 (1): 97–164. doi:10.1023/B:IJOP.0000014647.18720.32. Retrieved 2011-03-02. 
  7. ^ "Ternyata di Kalsel Ada Populasi Orangutan". October 10, 2014. 
  8. ^ Brandon-Jones, Douglas; Groves, Colin P.; Jenkins, Paulina D. (2016-09-09). "The type specimens and type localities of the orangutans, genus Pongo Lacépède, 1799 (Primates: Hominidae)". Journal of Natural History. 50 (33-34): 2051–2095. doi:10.1080/00222933.2016.1190414. ISSN 0022-2933. 
  9. ^ London, Zoological Society of (1905). Proceedings of the General Meetings for Scientific Business of the Zoological Society of London. Longmans, Green. 
  10. ^ "Definition of PYGMY". www.merriam-webster.com. Retrieved 2017-12-02. 
  11. ^ EDGE :: Mammal Species Information. Edgeofexistence.org. Retrieved on 2012-08-21.
  12. ^ Novak, R. M. 1999. Walker's Mammals of the World. 6th edition. Johns Hopkins University Press, Baltimore. ISBN 0-8018-5789-9
  13. ^ WWF – Sumatran Orangutan – Close relative in dire straits. Worldwildlife.org. Retrieved on 2012-08-21.
  14. ^ The Bornean and Sumatran Orangutans | Visuallens. Visuallens.wordpress.com (2008-08-02). Retrieved on 2012-08-21.
  15. ^ Wood, G. (1977). The Guinness Book of Animal Facts and Feats. New York: Sterling Pub. Co. ISBN 978-0-85112-235-9. 
  16. ^ a b Ciszek, D.; Schommer, M.K. (2009-06-28). "ADW: Pongo pygmaeus: Information". Animal Diversity Web. Retrieved 2009-07-03. 
  17. ^ Giza Zoo > Bornean Orangutan إنسان الغابة. Gizazoo-eg.com. Retrieved on 2012-08-21.
  18. ^ Wood, Gerald (1983). The Guinness Book of Animal Facts and Feats. ISBN 978-0-85112-235-9. 
  19. ^ Burnie, D. (2001). Animal. London: Dorling Kindersley. ISBN 140539109X. 
  20. ^ Macdonald, D. (2001). The New Encyclopedia of Mammals. Oxford: Oxford University Press. 
  21. ^ a b "Orangutan Fact Sheet". library.sandiegozoo.org. Retrieved 2017-12-02. 
  22. ^ a b c "Orangutans". WWF. Retrieved 2012-03-17. 
  23. ^ Bacon, A. M.; The Long, V. (September 2001). "The first discovery of a complete skeleton of a fossil orang-utan in a cave of the Hoa Binh Province, Vietnam". Journal of Human Evolution. 41 (3): 227–241. doi:10.1006/jhev.2001.0496. ISSN 0047-2484. PMID 11535001. 
  24. ^ a b c d e f Cawthon Lang, K.A. (2005). "Primate Factsheets: Orangutan (Pongo) Behavior". Primate Info Net. Retrieved 2011-03-02. 
  25. ^ "Orangutan". Sea World, Busch Gardens, & Discovery Cove. Retrieved 2012-03-17. 
  26. ^ "Primates: Orangutans". Smithsonian National Zoological Park. Archived from the original on 2011-04-14. Retrieved 2011-01-27. 
  27. ^ Cawthon Lang, K.A. (2005). "Primate Factsheets: Orangutan (Pongo) Taxonomy, Morphology, & Ecology". Primate Info Net. Retrieved 2011-07-23. 
  28. ^ Mackinnon, John (February 1974). "The behaviour and ecology of wild orang-utans (Pongo pygmaeus)" (PDF). Animal Behaviour. Elsevier Ltd. 22 (1): 3–74. doi:10.1016/S0003-3472(74)80054-0. ISSN 0003-3472. Retrieved 22 November 2017. 
  29. ^ Bleiman, B. (2008-04-29). "Orangutan "Spear Fishes"". Zooillogix. ScienceBlogs. Archived from the original on 2009-05-01. Retrieved 2009-07-03. 
  30. ^ Parker, S.T.; Mitchell, R.W.; Miles, H.L. (1999). The Mentalities of Gorillas and Orangutans: Comparative Perspectives. Cambridge: Cambridge University Press. ISBN 978-0-521-58027-4. 
  31. ^ Fox, E.A. (2002). "Female tactics to reduce sexual harassment in the sumatran orangutan (Pongo pygmaeus abelii)". Behavioral Ecology and Sociobiology. 52 (2): 93–101. doi:10.1007/s00265-002-0495-x. 
  32. ^ Kuze, Noko; Pratje, Peter; Banes, Graham L.; Pratje, Peter; Tajima, Tomoyuki; Russon, Anne E. (2011). "Factors affecting reproduction in rehabilitant female orangutans: young age at first birth and short inter-birth. interval". Primates. 53 (2): 181–92. doi:10.1007/s10329-011-0285-z. PMID 22109351. 
  33. ^ Cawthon Lang, K.A. (2005). "Primate Factsheets: Orangutan (Pongo) Conservation". Primate Info Net. Retrieved 2011-03-02. 
  34. ^ Bell, Loren (7 July 2016). "Bornean orangutan declared 'critically endangered' as forests shrink". The Guardian. Retrieved 2016-07-07. The Bornean orangutan (Pongo pygmaeus) is now critically endangered according to the International Union for Conservation of Nature (IUCN). 
  35. ^ Cheyne, S. M.; Thompson, C. J. H.; Phillips, A. C.; Hill, R. M. C.; Limin, S. H. (2007). "Density and population estimate of gibbons (Hylobates albibarbis) in the Sabangau catchment, Central Kalimantan, Indonesia" (PDF). Primates. 49 (1): 50–56. doi:10.1007/s10329-007-0063-0. PMID 17899314. Archived from the original (PDF) on 2009-03-26. 
  36. ^ Mayell, H. (2004-03-09). "Wild Orangutans: Extinct by 2023?". National Geographic. Retrieved 2011-03-03. 
  37. ^ Nellemann, C.; Miles, L.; Kaltenborn, B.P.; Virtue, M. & Ahlenius, H. (2007). The last stand of the orangutan – State of emergency: Illegal logging, fire and palm oil in Indonesia’s national parks (PDF) (Report). Norway: United Nations Environment Programme, GRID-Arendal. Retrieved 2011-03-03. 
  38. ^ "The Effects of Palm Oil – Orangutan Foundation International". Orangutan Foundation International. Retrieved 2017-12-02. 
  39. ^ a b Meijaard, Erik; Buchori, Damayanti; Hadiprakarsa, Yokyok; Utami-Atmoko, Sri Suci; Nurcahyo, Anton; Tjiu, Albertus; Prasetyo, Didik; Nardiyono; Christie, Lenny; Ancrenaz, Marc; Abadi, Firman; Antoni, I Nyoman Gede; Armayadi, Dedy; Dinato, Adi; Ella; Gumelar, Pajar; Indrawan, Tito P.; Kussaritano; Munajat, Cecep; Priyono, C. Wawan Puji; Purwanto, Yadi; Puspitasari, Dewi; Putra, M. Syukur Wahyu; Rahmat, Abdi; Ramadani, Harri; Sammy, Jim; Siswanto, Dedi; Syamsuri, Muhammad; Andayani, Noviar; Wu, Huanhuan; Wells, Jessie Anne; Mengersen, Kerrie; Turvey, Samuel T. (11 November 2011). Turvey, Samuel T, ed. "Quantifying Killing of Orangutans and Human-Orangutan Conflict in Kalimantan, Indonesia". PLoS ONE. 6 (11): e27491. Bibcode:2011PLoSO...627491M. doi:10.1371/journal.pone.0027491. PMC 3214049 Freely accessible. PMID 22096582. 
  40. ^ Marshall, Michael (15 November 2011). "Humans killing at least 750 Bornean orang-utans a year". The New Scientist. Retrieved 27 November 2011.  quoting Ashley Leiman, director of the Orangutan Foundation.
  41. ^ "Mass Slaughter of Orang-utans and Monkeys is Continuing in Kalimantan". November 24, 2011. 
  42. ^ Thompson, S. (2010). The Intimate Ape: Orangutans and the Secret Life of a Vanishing Species. Citadel Press. p. 54. ISBN 978-0-8065-3133-5. 
  43. ^ Weiss, A.; Adams, J. M.; King, E. J. (2011). "Happy orang-utans live longer lives". Biol. Lett. 7 (6): 872–874. doi:10.1098/rsbl.2011.0543. PMC 3210686 Freely accessible. 
  44. ^ "Killed by 40 Pellets". Retrieved December 10, 2014. 

Further reading[edit]

Russon, Anne E.; Compost, Alain; Kuncoro, Purwo; Ferisa, Agnes (December 2014). "Orangutan fish eating, primate aquatic fauna eating, and their implications for the origins of ancestral hominin fish eating". Journal of Human Evolution. 77: 50–63. doi:10.1016/j.jhevol.2014.06.007. PMID 25038033. 

External links[edit]

Retrieved from "https://en.wikipedia.org/w/index.php?title=Bornean_orangutan&oldid=857278631"