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Orangutan

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This article is about the primate. For the chess opening, see Sokolsky Opening.

Orangutans[1]
Scientific classification
Kingdom:
Animalia
Phylum:
Chordata
Class:
Mammalia
Order:
Primates
Family:
Hominidae
Subfamily:
Ponginae

Elliot, 1912
Genus:
Pongo

Type species
Simia pygmaeus
Linnaeus, 1760
Species

Pongo pygmaeus
Pongo abelii

Orangutan distribution

The orangutans are two species of great apes known for their intelligence and their long arms and reddish-brown hair. Native to Indonesia and Malaysia, they are currently found only in rainforests on the islands of Borneo and Sumatra, though fossils have been found in Java, Vietnam and China. They are the only extant species in the genus Pongo and the subfamily Ponginae (which also includes the extinct genera Gigantopithecus and Sivapithecus). Their name derives from the Malay and Indonesian phrase orang hutan, meaning "person of the forest".[2][3]

Etymology

The word orangutan (also written orang-utan, orang utan and orangutang) is derived from the Malay and Indonesian words orang meaning "person" and hutan meaning "forest", thus "man of the forest". Orang Hutan is the common term in these two national languages, although local peoples may also refer to them by local languages. Maias and mawas are also used in Malay, but it is unclear if those words refer only to orangutans, or to all apes in general.

The word was first attested in English in 1691 in the form orang-outang, and variants with -ng instead of -n as in the Malay original 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 by some.[4] However, dictionaries such as the American Heritage Dictionary regard forms with -ng as acceptable variants.

The name of the genus, Pongo, comes from a 16th century account by Andrew Battell, an English sailor held prisoner by the Portuguese in Angola, which describes two anthropoid "monsters" named Pongo and Engeco. It is now believed that he was describing gorillas, but in the late 18th century it was believed that all great apes were orangutans; hence Lacépède's use of Pongo for the genus.[5]

Ecology and appearance

Orangutans are the most arboreal of the great apes, spending nearly all of their time in the trees. Every night they fashion nests to sleep in from branches and foliage. They are more solitary than the other apes, with males and females generally coming together only to mate. Mothers stay with their babies until the offspring reach an age of six or seven years. There is significant sexual dimorphism between females and males: females can grow to around 4 ft 2 in or 127 centimetres and weigh around 100 lbs or 45 kg, while fully mature males can reach 5 ft 9 in or 175 centimetres in height and weigh over 260 lbs or 118 kg.[6] Fully mature males can be distinguished by their prominent cheek flanges and longer hair.

Bimodal Male Development

Adult male

Adult male orangutans exhibit two modes of physical development, flanged and unflanged. Flanged adult males have a variety of secondary sexual characteristics, including cheek pads (called "flanges"), throat pouch, and long fur, that are absent from both adult females and from unflanged males. Flanged males establish and protect territories that do not overlap with other flanged males' territories. Adult females, juveniles, and unflanged males do not have established territories. A flanged male's mating strategy involves establishing and protecting a territory, advertising his presence, and waiting for receptive females to find him. Unflanged males are also able to reproduce; their mating strategy involving finding females in estrus and forcing copulation. Males appear to remain in the unflanged state until they are able to establish and defend a territory, at which point they can make the transition from unflanged to flanged within a few months.[7] The two reproductive strategies, referred to as "call-and-wait" for flanged male and "sneak-and-rape" for the unflanged male, were found to be approximately equally effective in one study group.[8]

Diet

Orangutans eat mostly fruit which makes up 60% of their diet. Fruits with sugary or fatty pulp are favored. The fruit of fig trees are also commonly eaten since it is easy to both harvest and digest. Other food items include: young leaves, shoots, seeds and bark. Insects and bird eggs are also included.[9]

Orangutans are thought to be the sole fruit disperser for some plant species including the climber species Strychnos ignatii which contains the toxic alkaloid strychnine.[10] It does not appear to have any effect on orangutans except for excessive saliva production.

Behaviour and language

Orangutans at Singapore Zoo

Like the other great apes, orangutans are remarkably intelligent. Although tool use among chimpanzees was documented by Jane Goodall in the 1960s, it was not until the mid-1990s that one population of orangutans was found to use feeding tools regularly. A 2003 paper in the journal Science described the evidence for distinct orangutan cultures.[11]

According to recent research by Harvard University psychologist, James Lee, orangutans are the world's most intelligent animal other than man, with higher learning and problem solving ability than chimpanzees, which were previously considered to have greater abilities. A study of orangutans by Carel van Schaik, a Dutch primatologist at Duke University, found them capable of tasks well beyond chimpanzees’ abilities — such as using leaves to make rain hats and leakproof roofs over their sleeping nests. He also found that, in some food-rich areas, the creatures had developed a complex culture in which adults would teach youngsters how to make tools and find food.[12]

A two-week old orangutan

The first orangutan language study program, directed by Dr. Francine Neago, was listed by Encyclopedia Britannica in 1988. The Orangutan language project at the Smithsonian National Zoo in Washington, D.C., uses a computer system originally developed at UCLA by Neago in conjunction with IBM.[13] .

Orangutan "laughing"

Zoo Atlanta has a touch screen computer where their two Sumatran Orangutans play games. Scientists hope that the data they collect from this will help researchers learn about socializing patterns, such as whether they mimic others or learn behavior from trial and error, and hope the data can point to new conservation strategies. [14]

Although orangutans are generally passive, aggression toward other orangutans is very common; they are solitary animals and can be fiercely territorial. Immature males will try to mate with any female, and may succeed in forcibly copulating with her if she is also immature and not strong enough to fend him off. Mature females easily fend off their immature suitors, preferring to mate with a mature male.

Orangutans have even shown laughter-like vocalizations in response to physical contact, such as wrestling, play chasing, or tickling.

Species

Adult female orangutan

The populations on the two isolated islands were classified as subspecies until recently, when they were elevated to full specific level, and the three distinct populations on Borneo were elevated to subspecies. Some suggest that the subspecies wurmbii is conspecific with the Sumatra population (P. abelii). In that case, the resulting species, which would be distributed in Sumatra and southwestern Borneo, would be known as Pongo wurmbii, as that is the older name.[citation needed]

In addition, a fossil species, P. hooijeri, is known from 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. abeli or, in fact, represent distinct species.

Conservation status

A captive orangutan

The Bornean species of orangutans is highly endangered,[15] and the Sumatran species is critically endangered,[16] according to the IUCN Red List of mammals, and both are listed on Appendix I of CITES. The Borneo population is estimated at about 50,000 in the wild, while the Sumatran species is estimated at 7000-7500 individuals. The orangutan is an official state animal of Sabah in Malaysia.

Orangutan habitat destruction due to logging, mining and forest fires has been increasing rapidly in the last decade.[17] A major factor in that period of time has been the conversion of vast areas of tropical forest to oil palm plantations, for the production of palm oil.[18] Some UN scientists believe that these plantations could lead to the extinction of the species by the year 2012.[19] Much of this activity is illegal, occurring in national parks that are officially off limits to loggers, miners and plantation development.[citation needed] There is also a major problem with the poaching of baby orangutans for sale into the pet trade; the trappers usually kill the mother to steal the baby.[citation needed]

Major conservation centres in Indonesia include those at Tanjung Puting National Park in Central Kalimantan, Kutai in East Kalimantan, Gunung Palung National Park in West Kalimantan, and Bukit Lawang in the Gunung Leuser National Park on the border of Aceh and North Sumatra. In Malaysia, conservation areas include Semenggoh Wildlife Centre in Sarawak and Matang Wildlife Centre also in Sarawak, and the Sepilok Orang Utan Sanctuary near Sandakan in Sabah.

See also

The critically endangered Sumatran Orangutan, a great ape endemic to the islands of Sumatra and Borneo

References

  1. ^ a b 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.
  2. ^ "Orangutan Foundation International: All About Orangutans". Retrieved 2006-08-01.
  3. ^ "Tracking Orangutans from the Sky". PLoS Biol. 3 (1): e22. 2004. doi:10.1371/journal.pbio.0030022 unflagged free DOI (link).
  4. ^ "Orangutan". alphadictionary.com. Retrieved 2006-12-20.
  5. ^ Groves, Colin (2002). "A history of gorilla taxonomy" (PDF). Gorilla Biology: A Multidisciplinary Perspective, Andrea B. Taylor & Michele L. Goldsmith (editors). Cambridge University Press: pp. 15–34. {{cite journal}}: |pages= has extra text (help)
  6. ^ "Sumatran Orangutan Society". Retrieved 2007-04-01.
  7. ^ "Orangutan". Primate Info Net. Retrieved 2008-08-08.
  8. ^ Harrison, Mark E. (2007). "The orang-utan mating system and the unflanged male: A product of increased food stress during the late Miocene and Pliocene?". Journal of Human Evolution. 52 (3). {{cite journal}}: Unknown parameter |month= ignored (help)
  9. ^ Cawthon Lang KA (2005-06-13). "Primate Factsheets: Orangutan (Pongo) Taxonomy, Morphology, & Ecology". Retrieved 2007-10-12. {{cite web}}: Check date values in: |date= (help)
  10. ^ Rijksen, H. D. (1978). "A Field Study on Sumatran Orang Utans (Pongo pygmaeus abelii, Lesson 1827): Ecology, Behaviour and Conservation". The Quarterly Review of Biology. 53 (4). {{cite journal}}: Unknown parameter |month= ignored (help)
  11. ^ "Roads through rainforest threaten our cultured cousins". 2003. {{cite web}}: |first= missing |last= (help); Missing pipe in: |first= (help)
  12. ^ [1]
  13. ^ "Orangutan Language Project". Think Tank Research Projects. Smithsonian National Zoological Park. Retrieved 2006-12-20.
  14. ^ Turner, Dorie (2007-04-12). "Orangutans play video games at GA. zoo". Retrieved 2007-04-12. {{cite web}}: Check date values in: |date= (help)
  15. ^ Template:IUCN2006
  16. ^ Template:IUCN2006 Database entry includes justification for why this species is critically endangered
  17. ^ Rijksen, H.D. and Meijaard, E. (1999). Our Vanishing Relative: The Status of Wild Orang-utans at the Close of the Twentieth Century. Boston: Kluwer Academic Publishers. {{cite book}}: Text "Dordrecht" ignored (help)CS1 maint: multiple names: authors list (link)
  18. ^ http://www.foe.co.uk/resource/reports/oil_for_ape_summary.pdf
  19. ^ http://observer.guardian.co.uk/world/story/0,,2042243,00.html
Wikimedia Commons has media related to Pongo.
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Wikispecies has information related to Pongo.

General Information

Orangutan protection

In Borneo

In Sumatra

Photos and video

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