Pongo pygmaeus and Pongo abelii - Orangutan

Pongo pygmaeus and Pongo abelii - Orangutan

ORANGUTAN


Bornean orangutan

SCIENTIFIC CLASSIFICATION

Kingdom

:

Animalia

Phylum

:

Chordata

Subphylum

:

Vertebrata

Class

:

Mammalia

Order

:

Primates

Family

:

Hominidae

Kind

:

I pose

Species

:

Pongo pygmaeus (Bornean Orangutan)

Species

:

Pongo abelii (Sumatran orangutan)

Common name

: orangutan

GENERAL DATA

  • Length: max 1.5 m with an arm span of up to 2.5 m
  • Weight: female 36 - 50 kg; male: 60-90 kg
  • Lifespan: 35 - 45 years even if in captivity it has been seen that they can live up to 60 years
  • Sexual maturity: female 7 years; male: 10-15 years

HABITAT AND GEOGRAPHICAL DISTRIBUTION

The Orangutan, belonging to the Pongo genus of the Hominidae family, includes two species: Pongo pygmaeus o Bornean orangutan which lives only on the island of Borneo e I place abelii, Sumatran orangutan, which lives on the island of Sumatra.

The Bornean orangutans are found in the woods and forests within 1500 m of altitude (most of them are found within 500 m) scattered irregularly throughout the island even if it seems absent in the south-eastern areas. Large rivers represent insuperable barriers for orangutans as they cannot swim.

Sumatran orangutans are found in the northernmost part of the island, in the primary forests of the tropical lowland, including mangrove forests and can be found up to 1500 m of altitude.

CHARACTER, BEHAVIOR AND SOCIAL LIFE

Orangutans are tree-dwelling animals and are considered to be the largest tree mammals on earth. The undergrowth of the forests where they live are extremely intricate and it would be difficult to move on the ground but this is not a problem for orangutans as it lives, feeds and sleeps on trees (particularly valid for the Sumatran orangutan while the orangutan Borneo occasionally goes ashore). In this lifestyle they are helped by the arms and legs, both with prehensile hands / feet that allow you to support yourself and move from one tree to another without any difficulty.

They are not particularly social animals and do not live in large groups. Generally, the females live alone with the young, at most with another female and more rarely with an adult male. Generally, males and females only meet to mate. Each group of females has its own territory of 2-6 sq km which, however, often overlaps that of other females and males, while the territory of a male never overlaps with that of another male.

They are diurnal animals therefore at night they sleep on beds that are prepared every night on the tops of the trees.

It has been seen that orangutans are extremely intelligent animals that are able to learn and interpret the behavior of other animals. For example, it has been seen that they often follow fruit-eating birds to discover new fruit trees, just as it has been seen that during the rain they can tear off a large leaf and put it on their heads to shelter from the water.

Orangutans are very sociable and curious animals. Check out this video where there are several orangutans playing in a shelter center.

PHYSICAL CHARACTERISTICS

The orangutan is an animal that has a certain sexual dimorphism as the male is larger than the females. The whole body is covered with reddish-brown hair, particularly thick and long in the shoulders, functioning as rainproof. Sumatran hair is much longer than the Bornean orangutan and typically features tufts of white hair on the face and groin.


Bornean orangutan


Sumatran orangutan (1)

They feature a receding forehead, prominent snout, and fleshy cheeks that can puff up to both impress females and scare off rivals.

The legs are not particularly long and not too sturdy, so much so that they cannot bear the weight of the body in an upright position for a long time and are equipped with feet with five toes shaped so as to be suitable for grip; the arms are very long and sturdy including the hands formed by five fingers which allow you to grasp objects very firmly.

A peculiarity is that females reach maturity around 7 years, a period in which they also stop growing while males continue to grow up to 10-15 years, a period in which they also reach sexual maturity.

COMMUNICATION

Orangutans have several ways of communicating with each other: by voice, posture and touch. Males make long guttural sounds to keep other males away from their territory.

EATING HABITS

Orangutans are herbivorous animals but above all frugivores, feeding mainly on fruit (it represents 60% of their diet) but they can also eat leaves, flowers and tree bark. Their favorite fruits are the fruits of the Durio tree (Bombacaceae family) even if the fig represents the fundamental element of their diet because it ripens at different times of the year and therefore is more available.

The orangutan has an excellent memory and remembers the location of the trees where it can find fruit and also the times of the year when it ripens.

Often the same tree rich in fruit must be shared with other orangutans but also with other animals such as gibbons or birds and this represents one of the few moments of sociality that is allowed. More than 500 species of plants have been recorded, of which the orangutan is nourishes.Sometimes they also eat small insects, larvae and bird eggs.

REPRODUCTION AND GROWTH OF THE SMALL

Orangutans are polygamous animals and can mate at any time of the year.

The gestation lasts about 8 - 8.5 months at the end of which the female gives birth to a single baby weighing about half a kilo. For the first 4-6 months the baby never goes away from the mother and when he is four months old, he starts taking solid food from the mother's mouth. It is weaned around 3 - 3.5 years and tends to stay with its mother until the age of 8.

Up to the age of one year the baby remains attached to the mother's chest by clinging to the fur, beyond this period it attaches to the back and can continue to do so even up to 2.5 years of age.

The females remain by their mother's side even after she has given birth to a new baby to learn from her how to raise children.

The female orangutans are extremely caring mothers and are the only ones who take care of the young as the males do not care.

PREDATION

The orangutan doesn't have many predators. Mainly its biggest predator is the man followed by the large snakes and the birds of prey that can snatch the younger ones.

STATE OF THE POPULATION

The Bornean orangutan (Pongo pygmaeus) is classified in the IUNC Red list among animals at very high risk of extinction ENDANGERED (EN) having observed a decline in its population of 50% in the last 60 years. 2003 estimates indicate the population of Borneo at 45,000-68,000 specimens spread over 86,000 sq km but to date this figure is estimated to have significantly decreased.

The Sumatran orangutan (Pongo abelii) the IUNC Red list classifies it as CRITICALLY ENDANGERED (CR) that is to say critically endangered, therefore in an even more serious situation than the Bornean orangutan having observed a decline of more than 80% in the last 75 years. Estimates of 2004 indicate the population of this species equal to 7,300 specimens on a territory of about 9,000 sq km.

It has been estimated that if quick and decisive action is not taken, this decline will continue at the same rate for both species given the fact that their natural habitat is being destroyed due to the conversion of the forest into urban centers and agricultural areas. Other causes are: fires; wild deforestation, due to the increasing demand for timber; poaching, as orangutans are hunted both to be sold to zoos, for their meat and for some parts of their body used for traditional medicine.

Both species are listed in Annex I of CITES (Convention on International Trade in Endangered Species of Fauna and Flora, known simply as the "Washington Convention") which includes endangered species and therefore trade in specimens of such species. species is allowed only in exceptional cases.

It is established that, despite the islands where it lives there are several protected areas where the orangutan can live peacefully, most of its population lives in unprotected areas against which it is hoped that measures will be taken to try to curb the slow decline of this species.

SOCIAL, ECONOMIC AND ECOSYSTEM IMPORTANCE

The orangutan, in consideration of the fact that it is frugivorous and that it moves a lot, contributes significantly to the dispersion of seeds, especially the larger ones that cannot be dispersed by small animals.

Note

(1) Image not subject to copyright as it is licensed under Creative Commons.


Sumatran orangutan

The Sumatran orangutan (I place abelii) is one of the three species of orangutans. Found only in the north of the Indonesian island of Sumatra, it is rarer than the Bornean orangutan but more common than the recently identified Tapanuli orangutan, also found in Sumatra. Its common name is based on two separate local words, "orang" ("people" or "person") and "hutan" ("forest"), derived from the official language of Malaysia, Malay, [3] and translates as' person of the forest '.


The answer from DNA

Spotted for the first time in 1997, only in 2013 it was possible to sequence the DNA of this anibad. The occasion was provided by the discovery of an orangutan skeleton killed in a conflict with a man from the local population. From a first analysis of the skulls it seemed clear to the researchers that they were dealing with a different species. However, the definitive answer came by analyzing the genetic profile. The analyzes confirmed the hypotheses and showed that this species would have isolated itself from that of Pongo pygmaeus about 70 thousand years ago. "It's a blink of an eye for the history of evolution," Professor MIchael Krützen of the University of Zurich told the BBC.


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The threats

The forest where the orangutan lives are being destroyed at an ever-increasing rate and the cutting of trees, most often the fruit of illegal activities it is fueled by the growing demand for precious tropical woods and the demand for land to be converted to agriculture and the production of paper pulp.

In recent years, demand for palm oil has further fueled forest destruction. Most of the forests in the plains and hills are now occupied by extensive plantations of palm oil used in the food, cosmetics and bio-fuel sectors.

As a consequence today theorangutan survives in small and isolated forest areas, especially mountainous and this seriously compromises the medium and long term survival of this wonderful primate.
The reduction of the forest area pushes the orangutan to enter agricultural areas to search for food, and often he is killed because it damages crops, or becomes easy prey for poachers who sell its meat illegally.


Geographic Range

Sumatran orangutans inhabit the island of Sumatra, Indonesia. These orangutans have been restricted to the northern tip of Sumatra in fragmented forest. Logging has severely limited the range of this species. (Rijksen, 1978 Singleton and van Schaik, 2002 "Sumatran orangutan", 2007)

  • Biogeographic Regions
  • oriental
    • native
  • Other Geographic Terms
  • island endemic

Habitat

Sumatran orangutans are found in primary tropical lowland forests, including mangrove, swamp forests, and riparian forests. They live almost completely in the trees, building nests in which they nap or sleep for the night. Preferred elevations are 200 to 400 m, the area in which their preferred fruiting trees occur, but Sumatran orangutans can be found up to 1,000 to 1,500 m. (Rijksen, et al., 2003)

  • Habitat Regions
  • tropical
  • terrestrial
  • Terrestrial Biomes
  • rainforest
  • Wetlands
  • swamp
  • Other Habitat Features
  • riparian
  • Range elevation 200 to 1,500 m 656.17 to ft

Physical Description

Sumatran orangutans are the largest non-human primates in Asia and the largest arboreal primates. They have long, fine red hair on their bodies and faces. Males have large cheek pads that are covered in a fine white hairs The arm span, from finger tip to finger tip, is 2.25 m. The legs are small and weak compared to their muscular arms. There is sexual dimorphism between males and females. Female weights range from 30 to 50 kg and they can reach 1.3 m tall. Male weights range from 50 to 90 kg and reach a height of 1.8 m. Some old males may get too large to move around in trees easily and may have to resort to walking on the ground. (Maple, 1980 Rijksen, et al., 2003 Sumatran Orangutan Society, 2007 "Sumatran Orangutan- Population & Distribution", 2007)

Sumatran orangutans may be distinguished from Bornean orangutans (Pongo pygmaeus) by their longer fur, more slender build, white hairs on the face and groin, and long beards on both males and females, but molecular characters are considered most definitive. (Cocks, 2003)

  • Other Physical Features
  • endothermic
  • homoiothermic
  • bilateral symmetry
  • Sexual Dimorphism
  • male larger
  • sexes shaped differently
  • ornamentation
  • Mass range 30 to 90 kg 66.08 to 198.24 lb
  • Range length 1.3 to 1.8 m 4.27 to 5.91 ft

Reproduction

The primary mating tactic involves "harassment" of female Sumatran orangutans by sub-adult males and adult males. Most harassment involves sub-adult males females are less likely to mate with them, as compared to large adult males. Females are cornered by sub-adult males and may be raped by them these sub-adult males may also take a female's young from her if they think it will make her more willing or available to mate.

Female orangutans have learned strategic ways to avoid or reduce harassment. The first method is a social tactic, where females form non-mating parties with adult male orangutans that reside in their area, reducing attacks from sub-adult males. Another is female-female bonding, where females alone form alliances to protect themselves against sub-adult males.

Harassment has also increased in the last decade due to habitat loss from illegal logging. More orangutans are forced into too small of an area, increasing agonistic interactions. (Fox, 2002)

Most mating occurs in the heaviest fruiting months. There is large variability in the amount of fruit from season to season. Highest fruiting periods happen during rainy seasons (December to May). Mast fruiting years, in which most of the trees of a single species fruit synchronously, occur every 2 to 10 years. Sumatran orangutan breeding is most intense in mast years. Any female who is not currently caring for offspring (pre-weaning) is available to mate. Females normally mate with the adult male whose large territory they live in, but chance encounters can happen in high fruiting seasons when many orangutans gather to feed. Females give birth to one young, twinning occurs rarely. (Wich, et al., 2004 Fox, 2002 Wich, et al., 2004)

Adult female Sumatran orangutans become sexually active at the average age of 12.3 yrs and will produce their first offspring soon after. Male Sumatran orangutans are fully mature at an average age of 19 years. (Fox, 2002 Wich, et al., 2004)

  • Key Reproductive Features
  • iteroparous
  • seasonal breeding
  • gonochoric / gonochoristic / dioecious (sexes separate)
  • sexual
  • viviparous
  • Breeding interval Interbirth intervals are 3 to 4 years.
  • Breeding season Rainy seasons: December and May
  • Range number of offspring 1 to 2
  • Average number of offspring 1
  • Range gestation period 227 to 275 days
  • Average weaning age 48 months
  • Range time to independence 8 to 9 years
  • Average time to independence 9.3 years
  • Range age at sexual or reproductive maturity (female) 9 to 15.5 years
  • Average age at sexual or reproductive maturity (female) 12.3 years
  • Range age at sexual or reproductive maturity (male) 15 to 24 years
  • Average age at sexual or reproductive maturity (male) 19 years

After a female orangutan has given birth, her next 8 to 9 years are devoted to her offspring's survival. Infant and juvenile orangutans must learn everything (feeding, social behaviors, etc.) from their mothers. Mothers provide young orangutans with food until they have learned to distinguish different types of food. Males do not play a role in offspring care. Once fully developed, a male will leave his mother to find his own territory. A developed, independent young female will either disperse or take up residence near her mother's territory. (Fox, 2002 Wich, et al., 2004)

  • Parental Investment
  • altricial
  • female parental care
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching / birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning / fledging
    • provisioning
      • female
    • protecting
      • female
  • pre-independence
    • provisioning
      • female
    • protecting
      • female
  • post-independence association with parents
  • extended period of juvenile learning

Lifespan / Longevity

Female life spans range from 44 to 53 years in the wild. There have been no reports documenting the onset of menopause and females seem to be capable of giving birth up to 51 to 53 years old. Male life spans are slightly longer, 47 to 58 years. Males are still considered healthy at these late ages by the tightness of their cheek pads and absence of bald spots. A captive female Sumatran orangutan lived to 55 years at the Miami Zoo. (Rijksen, 1978 Rijksen, et al., 2003)

  • Range lifespan
    Status: wild 44 to 58 years
  • Range lifespan
    Status: captivity 55 (high) years
  • Typical lifespan
    Status: wild 58 (high) years

Behavior

Wild orangutans are almost completely arboreal except for occasional forays on the ground. Exceptionally large males spend more time traveling on the ground, possibly because many trees cannot sustain their weight. Sumatran orangutans are active during the day and build new nests in trees each night in which to sleep. Nests are built with bent branches, sticks, and leaves. Young orangutans use brachiation extensively, but older, larger orangutans tend to use hand over hand motion. Sumatran orangutans are more social than Bornean orangutans (Pongo pygmaeus), spending more time in small groups. (Maple, 1980)

Grooming is a major source of social interaction in most primates, but there are few grooming techniques used by Sumatran orangutans, which are more solitary. Females occasionally scratch and preen each other. Social grooming has only been documented on the upper part of the body. Mother-offspring grooming has only been seen in zoos. In this case, most mothers have to hold down their offspring once the young are capable of independent locomotion. They also cut toenails and fingernails with their teeth. Most mother-offspring grooming is done by mouth hands are rarely used. When grooming, they normally use one finger, moving it in one direction. The same technique is used for itching, but the whole hand or arm is used. When self-grooming, orangutans flip through their hair with their lips and mouth. They only attend to areas they can see and reach. (Maple, 1980)

Play is either non-social or social and has been recognized in adults and juveniles. Juveniles exhibit a surprisingly high amount of playful interactions, such as non-aggressive biting. Actual contact is not always necessary, sometimes simple body language is used as play. Compared to all other great apes, orangutans are capable of the most facial expression, due to their very flexible lips. Sumatran orangutans are exceptionally intelligent and capable of learning complex tasks and language. (Maple, 1980)

  • Key Behaviors
  • arboreal
  • scansorial
  • diurnal
  • motile
  • nomadic
  • solitary
  • territorial
  • Range territory size 5 to 25 km ^ 2

Home Range

Males and females share overlapping home ranges. Females range from 500 to 850 ha areas that overlap with each other. Male territories have a minimum range of 2,500 ha that will cover up to three female territories. (Fox, 2002 Maple, 1980 Singleton and van Schaik, 2002)

Communication and Perception

Male Sumatran orangutans are capable of long, exceptionally loud calls (called "long calls") that carry through forests for up to 1 km. The "long call" is made up of a series of sounds followed by a bellow. These calls help males claim territory, call to females, and keep out intruding male orangutans. Males have a large throat sac that lets them make these loud calls. They may also pull small trees and limbs down to add a crashing sound along with the call. Sumatran orangutans vocalize with grunts, grumbles, and squeaks when they meet each other, and young orangutans squeak, bark and scream. Both adults and young make a variety of sounds with their lips and throats, including sucking, burping, and grinding their teeth. (Maple, 1980)

  • Communication Channels
  • visual
  • tactile
  • acoustic
  • Perception Channels
  • visual
  • tactile
  • acoustic
  • chemical

Food Habits

Sumatran orangutan food choices vary seasonally. Most fruits are only available seasonally and within a limited range. Orangutans follow the fruiting season of local trees, feeding when they are ripe. Figs are one of the most important components of the Sumatran orangutan diet. During dry seasons, when fruit is less available, Sumatran orangutans will consume other vegetation. Fruit makes up about 60% of their diet, with the remainder being young leaves (

10%), insects, mainly ants, termites, and crickets (

  • Primary Diet
  • herbivore
    • frugivorous
  • Animal Foods
  • eggs
  • insects
  • Plant Foods
  • leaves
  • wood, bark, or stems
  • seeds, grains, and nuts
  • fruit
  • flowers

Predation

The primary predators currently of Sumatran orangutans are humans (Homo sapiens). Hunting of orangutans has decimated their populations. Natural predators of Sumatran orangutans are clouded leopards (Neofelis nebulosa) and Sumatran tigers (Panthera tigris sumatrae). These predator species are also under threat of extinction due to hunting by humans. (MacKinnon, 1974)

  • Known Predators
    • clouded leopards (Neofelis nebulosa)
    • Sumatran tigers (Panthera tigris sumatrae)
    • humans (Homo sapiens)

Ecosystem Roles

Sumatran orangutans play a critical role in the lowland rainforests of Sumatra and are considered a keystone species. As widely ranging fruit eaters, orangutans are important in dispersing seeds and maintaining diversity of rainforest woody plants. They also prune and aid in regenerating plant growth because they only choose to eat green leaves and stalks. ("Sumatran Orangutan- Population & Distribution", 2007 "Sumatran orangutan", 2007)

  • Ecosystem Impact
  • disperses seeds
  • keystone species

Economic Importance for Humans: Positive

Sumatran orangutans are important in seed dispersal. The protected status of orangutans make them an umbrella species. As umbrella species, if orangutans are protected, so is the rainforest they inhabit and all of its associated biodiversity.

There is still an active illegal trade in orangutans as pets. (Thompson, 2007)

  • Positive Impacts
  • pet trade
  • research and education

Economic Importance for Humans: Negative

There are no known negative affects of orangutans on humans. They are susceptible to many of the same diseases as humans, and thus can carry and transmit them as well, including tuberculosis, meliodosis, influenza, cholera, and intestinal parasites.

  • Negative Impacts
  • injures humans
    • carries human disease

Conservation Status

Critical orangutan habitat is rapidly being lost through illegal and legal logging in Sumatra. Their habitat has decreased over 80% in the last 20 years. Hunting orangutans for meat and killing adult females to obtain infants for the illegal pet trade has also caused an estimated decline in the orangutan population of 30 to 50% in the last 10 years. Uncontrolled forest fires have also harmed orangutan habitat. ("Sumatran Orangutan", 2006 Thompson, 2007 "Sumatran Orangutan- Population & Distribution", 2007 "Sumatran orangutan", 2007)

  • IUCN Red List Critically Endangered
    More information
  • IUCN Red List Critically Endangered
    More information
  • US Federal List Endangered
  • CITES Appendix I
  • State of Michigan List No special status

Other Comments

Sumatran and Bornean orangutans were previously considered subspecies of Pongo pygmaeus. They were recently split into two species, Bornean orangutans (Pongo pygmaeus) and Sumatran orangutans (Pongo abelii).

In 2006, a subadult female that was captive-born was released into the wild from Perth Zoo in Jambi, Sumatra. This is the first attempt to release a captive-born orangutan into the wild. (Cocks and Bullo, 2008 Singleton, et al., 2007)

Fossil evidence suggests that Sumatran orangutans once occurred throughout Sumatra and the island of Java. (Wich, et al., 2004)

Contributors

Tanya Dewey (editor), Animal Diversity Web.

Kelle Urban (author), Radford University, Karen Powers (editor, instructor), Radford University.

Glossary

uses sound to communicate

young are born in a relatively underdeveloped state they are unable to feed or care for themselves or locomote independently for a period of time after birth / hatching. In birds, naked and helpless after hatching.

Referring to an animal that lives in trees tree-climbing.

having body symmetry such that the animal can be divided into one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

uses smells or other chemicals to communicate

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor the fossil record does not distinguish these possibilities. Convergent in birds.

parental care is carried out by females

an animal that mainly eats fruit

An animal that eats mainly plants or parts of plants.

animals that live only on an island or set of islands.

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

a species whose presence or absence strongly affects populations of other species in that area such that the extirpation of the keystone species in an area will result in the ultimate extirpation of many more species in that area (Example: sea otter).

having the capacity to move from one place to another.

the area in which the animal is naturally found, the region in which it is endemic.

generally wanders from place to place, usually within a well-defined range.

found in the oriental region of the world. In other words, India and southeast Asia.

the business of buying and selling animals for people to keep in their homes as pets.

the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).

breeding is confined to a particular season

reproduction that includes combining the genetic contribution of two individuals, a male and a female

one of the sexes (usually males) has special physical structures used in courting the other sex or fighting the same sex. For example: antlers, elongated tails, special spurs.

a wetland area that may be permanently or intermittently covered in water, often dominated by woody vegetation.

uses touch to communicate

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

uses sight to communicate

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

References

Zoological Parks and Gardens Board of Victoria. 2004. "Sumatran Orangutan" (On-line). Accessed October 17, 2007 at http://www.zoo.org.au/education/factsheets/mam-sum_orang.pdf.

Durrell Wildlife Conservation Trust. Sumatran Orangutan. 69. Durrell Wildlife Conservation Trust: Durrell Wildlife Conservation Trust. 2006. Accessed November 26, 2007 at http://www.durrell.org/Animals/Sumatran-Orangutan/.

Cocks, L., K. Bullo. 2008. The processes for releasing a zoo-bred Sumatran orang-utan Pongo abelii at Bukit Tigapuluh National Park, Jambi, Sumatra. International Zoo Yearbook (OnlineEarly Articles), 42: XXX-XXX. Accessed January 09, 2008 at http://www.blackwell-synergy.com/doi/abs/10.1111/j.1748-1090.2007.00031.x.

Cocks, L. 2003. Orangutans: And Their Battle for Survival. Claremont, West Australia: University of Western Australia Press.

Fox, E. 2002. Female tactics to reduce sexual harassment. Behavioral Ecology and Sociobiology, 52/2: 93-101.

Lovell, N. 1990. Patterns Of Injury and Illness in Great Apes. United States of America: Smithsonian Institution.

MacKinnon, J. 1974. In Search Of The Red Ape. Ballantine Books A Division of Random House, Inc. New York, NY: Holt, Rinehart and Winston.

Maple, T. 1980. Orang-utan Behavior. Van Nostrand Reinhold Company. New York, NY: Van Nostrand Reinhold Company.

Rijksen, H. 1978. A field study on Sumatran oran utans (Pongo abelii): ecology, behavious and conservation .. WAU Dissertation Abstracts, Dissertation no. 710: 1-2. Accessed September 26, 2007 at http://library.wur.nl/wda/abstracts/ab710.html.

Rijksen,, Meijaard, Van Schaik. 2003. "DISTRIBUTION & HABITAT" (On-line). Accessed November 29, 2007 at http://spot.colorado.edu/

Singleton, I., S. Wich, M. Griffiths. 2007. "Pongo abelii" (On-line). IUCN 2007. 2007 IUCN Red List of Threatened Species .. Accessed December 11, 2007 at http://www.iucnredlist.org/search/details.php/39780/summ.

Singleton, I., C. van Schaik. 2002. The Social Organization of a Population of Sumatran Orang-Utans. Karger Journals, 73: 1-20. Accessed September 26, 2007 at http://content.karger.com/ProdukteDB/produkte.asp?typ=pdf&doi=60415.

Sumatran Orangutan Society, 2007. "Orangutan Facts" (On-line). Sumatran Orangutan Society. Accessed December 11, 2007 at http://www.orangutans-sos.org/faq.php.

Thompson, G. 2007. "Orangutans sacrificed in palm oil boom" (On-line). ABC News. Accessed December 04, 2007 at http://www.abc.net.au/news/stories/2007/12/04/2108675.htm.

Wich, S., S. Utami-Atmoko, T. Mitra Setia, H. Rijksen, C. Schürmann. 2004. Life history of wild Sumatran orangutans ( Pongo abelii ). Journal of Human Evolution , 47/6: 385-398.

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Geographic Range

Bornean orangutans ( Pongo pygmaeus ) are currently found on the Southeast Asian island of Borneo and generally inhabits swampy and hilly tropical rainforests. Bornean orangutans have a patchy distribution throughout the island and is completely absent from the southeast region. Fossil evidence suggests that Bornean orangutans were once widespread throughout Southeast Asia and evenly distributed across the entire island of Borneo. Due to illegal logging and the destruction and conversion of tropical forest to agricultural land this once expansive range has decreased dramatically. ("Great Apes and Other Primates", 2011 Ancrenaz, et al., 2008 Lang, 2010 Schulz, et al., 2011)

  • Biogeographic Regions
  • oriental
    • native
  • Other Geographic Terms
  • island endemic

Habitat

Bornean orangutans are arboreal and rarely descend to the ground. They generally live in the old growth forests ranging from the lowland swampy areas to the dipterocarp forests. The peat swamps and flood-prone dipterocarp forests produce more fruit than the dry dipertocarp forests and have a higher density of Bornean orangutans because they migrate depending on fruit availability. Bornean orangutans inhabit the primary tropical rainforest and secondary forest at lower elevations and are rarely seen above elevations of 1000 meters. (Ancrenaz, et al., 2008 Groves, 1971 Lang, 2010 Pamungkas and Marshall, 2005)

  • Habitat Regions
  • tropical
  • terrestrial
  • Terrestrial Biomes
  • rainforest
  • Wetlands
  • swamp
  • Range elevation 0 to 1000 m 0.00 to 3280.84 ft
  • Average elevation ft

Physical Description

Bornean orangutans have orange-red hair and long arms, which are advantageous for traveling through the canopy. Bornean orangutans grasp with both their feet and hands, which suites their arboreal life. Both sexes have throat pouches for calling but the male’s throat pouches are larger than the females. Bornean orangutans are sexually dimorphic, with males having an average height and weight of 970 mm and 87 kg respectively, and females averaging 780 mm and 37 kg, respectively. Males also develop large cheek pads known as flanges and develop a sagittal crest where large temporal muscles attach. ("Great Apes and Other Primates", 2011 Ancrenaz, et al., 2008 Groves, 1971 Lang, 2010)

Bornean orangutans exhibit bimaturism, or two different forms of mature males. These two types of males are denoted as being either flanged and unflanged. Flanged males are twice the size of females, have a large facial disk with flanges, and a large throat patch. Unflanged males look much more like the females as they are the same size and do not display the same calling behavior as flanged males. Both types of adult male orangutans reproduce in the population. Unflanged males may become flanged at any time, as it is a reflection of social hierarchy as well as age. Males between 8 and 15 years of age are generally unflanged and become flanged between 15 and 20. (Ancrenaz, et al., 2008 Lang, 2010)

Bornean orangutans are distinguishable from their Sumatran cousins in their morphology. After diverging 1.5 million years ago, Bornean orangutans have become heavier and thicker, have darker red coats, long course hair, and the males have larger flanges covered in bristly hair and larger throat pouches. (Ancrenaz, et al., 2008 Lang, 2010)

  • Other Physical Features
  • endothermic
  • bilateral symmetry
  • Sexual Dimorphism
  • male larger
  • ornamentation
  • Average mass 87 kg 191.63 lb
  • Average mass 64475 g 2272.25 oz AnAge
  • Average length 970 mm 38.19 in

Reproduction

Dominant flanged males often have an established territory that will encompass multiple females' territories. The multiple females within the male’s territory will copulate with him and produce his offspring. Younger unflanged males often cannot sustain a home range of their own and are forced to wander throughout the forests. When these small, wandering males come into contact with a female, the small unflanged male will force copulation. This is different from the flanged males which will long-call a call to help receptive females locate him. Females prefer to mate with flanged males, which may be a way to ensure protection from unflanged males. (Ancrenaz, et al., 2008 Groves, 1971 Lang, 2010)

  • Mating System
  • polygynous

Bornean orangutans do not have a breeding season, but females show higher ovarian function during periods of food abundance. Ovulation in Bornean orangutans occurs on the 15th day of a 30-day cycle. Copulation generally occurs with both parties hanging with their arms and facing each other. Bornean orangutan's gestation period lasts about nine months after which they give birth to a single infant, although twins have been recorded. Research shows that female orangutans only breed every 6 to 8 years, and the young are nursed until age 6 and remain at the mother's side until the next birth. The offspring has contact with its mother after birth, but once female offspring start to display sexual behaviors, they begin traveling separately. Once the female offspring is separated from its mother completely, it will move off and establish a territory nearby its mother’s territory. Adolescence in Bornean orangutans starts at 5 years of age and lasts until around 8 years of age. Male offspring remain socially immature despite being sexually mature. The young males avoid contact with mature males and start to wander the forests until they become a flanged male and establish their own resident territory. Female Bornean orangutans will reach menopause around the age of 48 years. (Ancrenaz, et al., 2008 Groves, 1971 Lang, 2010)

  • Key Reproductive Features
  • iteroparous
  • year-round breeding
  • gonochoric/gonochoristic/dioecious (sexes separate)
  • sexual
  • viviparous
  • Breeding interval Female orangutans breed every 8 years.
  • Breeding season Bornean orangutans breed year-round.
  • Range number of offspring 1 to 2
  • Average number of offspring 1
  • Average number of offspring 1 AnAge
  • Range gestation period 233 to 263 days
  • Average gestation period 245 days
  • Range weaning age 36 to 84 months
  • Average weaning age 42 months
  • Range time to independence 5 to 8 years
  • Average time to independence 7 years
  • Range age at sexual or reproductive maturity (female) 5.8 to 11.1 years
  • Range age at sexual or reproductive maturity (male) 8 to 15 years

Female Bornean orangutans invest a lot of time in their offspring, taking care of them until they reach adolescence at around 6 years of age. Since Bornean orangutans are semi-solitary in nature, the males have very little contact and no investment in their young. From birth, the offspring will be in constant contact with the mother for 4 months and will be carried everywhere the mother goes. The offspring remains completely dependent upon the mother for the first 2 years of life. At about 5 years of age, the offspring will begin to make short trips on its own, usually staying within sight of the mother. The orangutan young may start to build its own nests as play, and will eventually start sleeping in the nests it builds. The offspring are usually weaned by 4 years of age and will begin adolescence soon after. The offspring will generally stay around the mother until the next offspring are born. After this, the young females establish their own territory and the young males travel the forest until they can establish their own home territory. ("Great Apes and Other Primates", 2011 Ancrenaz, et al., 2008 Lang, 2010)

  • Parental Investment
  • precocial
  • female parental care
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female
  • pre-independence
    • provisioning
      • female
    • protecting
      • female
  • extended period of juvenile learning

Lifespan/Longevity

Bornean orangutans are long lived like many of the other great ape species. They often live more than 50 years in the wild and have been documented to live up to 59 years in captivity. ("AnAge entry for Pongo pygmaeus", 2009 Lang, 2010)

  • Range lifespan
    Status: wild 50 (high) years
  • Range lifespan
    Status: captivity 59 (high) years
  • Average lifespan
    Status: captivity 59.0 years Max Planck Institute for Demographic Research
  • Average lifespan
    Sex: female
    Status: captivity 57.3 years Max Planck Institute for Demographic Research
  • Average lifespan
    Status: wild 59.0 years Max Planck Institute for Demographic Research
  • Average lifespan
    Sex: male
    Status: captivity 58.8 years Max Planck Institute for Demographic Research
  • Average lifespan
    Status: wild 35.0 years Max Planck Institute for Demographic Research
  • Average lifespan
    Status: captivity 50.0 years Max Planck Institute for Demographic Research

Behavior

Bornean orangutans are diurnal and rarely come down from the trees. Small groups of females may travel with their infants in search of food, but adult males are usually solitary. While all Bornean orangutans are generally solitary they may have occasional social connections. Groups of 6 or more Bornean orangutans are rare but can be found during times of mast fruiting when a group of trees suddenly fruit at the same time. Daily and seasonal movements change frequently and are influenced by the availability of fruit. Bornean orangutans use multiple methods of locomotion. Brachiation is only seen in young orangutans whereas older orangutans walk quadrupedally, or occasionally bipedally. When walking quadrupedally, they walk on their fists rather than their knuckles, unlike other great apes. Bornean orangutans sleep in nest platforms made of vegetation 40 to 60 feet off the ground. Food is plucked with the fingers and the palm due to their inability to use their thumbs. Bornean orangutans cannot swim which make rivers and other water sources impassable boundaries, limiting their range. ("Great Apes and Other Primates", 2011 Ancrenaz, et al., 2008 Groves, 1971 Lang, 2010 Pamungkas and Marshall, 2005 Schulz, et al., 2011)

  • Key Behaviors
  • arboreal
  • diurnal
  • motile
  • solitary
  • territorial
  • dominance hierarchies
  • Range territory size 2 to 6 km^2

Home Range

Adult male Bornean orangutans can have home ranges from 2 to 6 sq km and will often incorporate multiple female home ranges. When a young female is establishing her home range, she will often choose a range nearby or bordering her mother's range. (Ancrenaz, et al., 2008 Lang, 2010)

Communication and Perception

Bornean orangutans are not as social as other species of great apes and do not have as many social vocalizations. The most prominent form of communication for Bornean orangutans is the long-call, a one to two minute call performed only by flanged males. The long-call can be heard from several kilometers away in the right conditions. The main purposes of long-calls are to inform other males of the caller's presence (when unflanged males hear long-calls they flee the area) and to call out to sexually responsive females. Long-calls are spontaneous and do not follow any specific pattern. Some evidence suggests that the long-call can even suppress the development of unflanged males. When the unflanged males hear a long-call, stress hormones are produced which inhibit the development of the unflanged males. The other type of calling produced by Bornean orangutans is a fast-call, which is most often made after male-to-male conflict. In addition to the long and fast calls, Bornean orangutans smack their lips to produce sounds when in small social groups. When scared, Bornean orangutans will funnel their lips and scream. (Ancrenaz, et al., 2008 Groves, 1971 Lang, 2010)

  • Communication Channels
  • visual
  • acoustic
  • Perception Channels
  • visual
  • tactile
  • acoustic
  • chemical

Food Habits

Bornean orangutans are frugivorous, and spend two to three hours in the morning feeding avidly. Their diet consists of forest fruits, leaves and shoots, insects, sap, vines, spider webs, bird eggs, fungi, flowers, barks, and occasionally nutrient rich soils. Bornean orangutans have been documented eating more than 500 plant species as part of their diet. Fruits make up more than 60% of their total dietary intake and they will migrate depending on fruit availability. ("Great Apes and Other Primates", 2011 Ancrenaz, et al., 2008 Groves, 1971 Lang, 2010 Pamungkas and Marshall, 2005)

  • Primary Diet
  • herbivore
    • frugivore
  • Animal Foods
  • eggs
  • insects
  • terrestrial worms
  • Plant Foods
  • leaves
  • roots and tubers
  • wood, bark, or stems
  • fruit
  • nectar
  • flowers
  • sap or other plant fluids
  • Other Foods
  • fungus
  • detritus

Predation

The only predator of Bornean orangutans are humans. Even hunting for traditional purposes at a 2% hunting rate, is not sustainable for the current population of orangutans. Bornean orangutans are not subject to predation from large felines like their Sumatran cousins, although clouded leopards are able take down a young Bornean orangutan. (Ancrenaz, et al., 2008 Groves, 1971 Lang, 2010)

  • Anti-predator Adaptations
  • cryptic
  • Known Predators
    • humans (Homo sapiens)
    • clouded leopards (Neofelis nebulosa)

Ecosystem Roles

Since fruits make up more than 60% the Bornean orangutan diet, they play a vital role in seed dispersal, especially for the larger seeds which cannot be dispersed by smaller animals. Bornean orangutans play such a crucial role in seed dispersal that they have been given the title "gardeners of the forest". (Ancrenaz, et al., 2008)

  • Ecosystem Impact
  • disperses seeds

Economic Importance for Humans: Positive

The Bornean orangutans keep the forests healthy by dispersing seeds, and eco tourism for the Bornean orangutans draws in important revenue for orangutan conservation agencies. (Ancrenaz, et al., 2008 Lang, 2010)

  • Positive Impacts
  • ecotourism

Economic Importance for Humans: Negative

Bornean orangutans have the highest density in areas where there is valuable timber such as the peat swamps. In the second half of the 19th century, the Bornean orangutans lost 80% of its viable habitat. These forests are also being illegally logged, as people are logging before the 30 to 40 year rest period is over. Palm oil tree saplings are eaten after logging occurs and the orangutans are searching for another food source. The Bornean orangutans also compete with humans for durian fruit and will on rare occasions attack humans. (Ancrenaz, et al., 2008 Groves, 1971)

  • Negative Impacts
  • injures humans
  • crop pest

Conservation Status

Bornean orangutans are an endangered species. Since all Bornean orangutans are totally depenent on the trees for survival, forest degradation is devastating to the population. Even though the fruiting trees are not the coveted timber, the removal of trees from the area still negatively influences the overall quality of the forest. Because Bornean orangutans have to travel to find the fruiting trees, a patchy forest hinders travel and dispersal and increases competition for these limited resources. ("Pongo pygmaeus", 2012 Ancrenaz, et al., 2008 Lang, 2010)

If the Bornean orangutan is going to recover, habitat destruction must be stopped. These orangutans also need to be protected, and any harvesting for meat or for illegal pet trade must be stopped. Both of these current practices are not sustainable and may lead to the extinction of the Bornean orangutans. (Groves, 1971 Lang, 2010)

Contributors

Benjamin Strobel (author), University of Wisconsin-Stevens Point, Christopher Yahnke (editor), University of Wisconsin-Stevens Point, Alecia Stewart-Malone (editor), University of Wisconsin-Stevens Point, Laura Podzikowski (editor), Special Projects.

Glossary

uses sound to communicate

Referring to an animal that lives in trees tree-climbing.

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

uses smells or other chemicals to communicate

having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment being difficult to see or otherwise detect.

particles of organic material from dead and decomposing organisms. Detritus is the result of the activity of decomposers (organisms that decompose organic material).

ranking system or pecking order among members of a long-term social group, where dominance status affects access to resources or mates

humans benefit economically by promoting tourism that focuses on the appreciation of natural areas or animals. Ecotourism implies that there are existing programs that profit from the appreciation of natural areas or animals.

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor the fossil record does not distinguish these possibilities. Convergent in birds.

parental care is carried out by females

an animal that mainly eats fruit

An animal that eats mainly plants or parts of plants.

animals that live only on an island or set of islands.

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

having the capacity to move from one place to another.

the area in which the animal is naturally found, the region in which it is endemic.

found in the oriental region of the world. In other words, India and southeast Asia.

having more than one female as a mate at one time

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

reproduction that includes combining the genetic contribution of two individuals, a male and a female

one of the sexes (usually males) has special physical structures used in courting the other sex or fighting the same sex. For example: antlers, elongated tails, special spurs.

a wetland area that may be permanently or intermittently covered in water, often dominated by woody vegetation.

uses touch to communicate

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

uses sight to communicate

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

breeding takes place throughout the year

young are relatively well-developed when born

References

2011. "Great Apes and Other Primates" (On-line). Smithsonian National Zoological Park. Accessed August 15, 2011 at http://nationalzoo.si.edu/Animals/Primates/Facts/FactSheets/Orangutans/default.cfm.

2012. "Pongo pygmaeus" (On-line). The IUCN Red List of Threatened Speces. Accessed October 26, 2012 at http://www.iucnredlist.org/details/17975/0.

Ancrenaz, M., A. Marshall, B. Goossens, C. Van Schaik, J. Sugardjito, M. Gumal, S. Wich. 2008. "The IUCN Red List of Threatened Species" (On-line). Pongo pygmaeus. Accessed August 15, 2011 at http://www.iucnredlist.org/apps/redlist/details/17975/0.

Call, J. 2004. Inferences about the location of food in the Great Apes (Pan paniscus, Pan trogodytes, Gorilla gorilla, and Pongo pygmaeus). Journal of Comparative Psychology , 118: 232-241. Accessed August 15, 2011 at http://www.cs.arizona.edu/projects/wonac/papers/Call2004JCP.pdf.

Groves, C. 1971. Pongo pygmaeus. American Society of Mammalogists , 4: 1-6. Accessed August 15, 2011 at http://www.science.smith.edu/msi/pdf/i0076-3519-004-01-0001.pdf.

Lang, K. 2010. "National Primate Research Center, University of Wisconsin - Madsion" (On-line). Primate Info Net. Accessed August 15, 2011 at http://pin.primate.wisc.edu/factsheets/entry/orangutan/taxon.

Pamungkas, B., A. Marshall. 2005. A survey of the orangutan (Pongo pygmaeus wurbii) population in and around Gunung Palung National Park, West Kalimantan, Indonesia based on nest counts. Biological Conservation , 121: 495-507. Accessed August 15, 2011 at http://anthropology.ucdavis.edu/people/andrew-j.-marshall-1/publications-1/Johnson%20et%20al.%202005-GP%20orangutan%20census.pdf.

Schulz, K., L. Shapiro, M. Frаnkis. 2011. "Encyclopedia of Life" (On-line). Pongo pygmaeus. Accessed August 15, 2011 at http://www.eol.org/pages/326450.

Zhang, Y., O. Ryder, Y. Zhang. 2001. Genetic Divergence of Orangutan Subspecies (Pongo pygmaeus). Journal of Molecular Evolution , 52: 516-526. Accessed August 15, 2011 at http://159.226.149.45/zhang/achievements/publications/2001/Zhang%20YW-JME2001.pdf.

The Animal Diversity Web team is excited to announce ADW Pocket Guides!


Orang-utan FAQs (Frequently Asked Questions)

Are Orang-utans herbivores, carnivores, or omnivores?

Orang-utans are Omnivores, meaning they eat both plants and other animals.

What Kingdom do Orang-utans belong to?

Orang-utans belong to the Kingdom Animalia.

What class do Orang-utans belong to?

Orang-utans belong to the class Mammalia.

What phylum to Orang-utans belong to?

Orang-utans belong to the phylum Chordata.

What family do Orang-utans belong to?

Orang-utans belong to the family Hominidae.

What order do Orang-utans belong to?

Orang-utans belong to the order Primates.

What type of covering do Orang-utans have?

Orang-utans are covered in Hair.

What genus do Orang-utans belong to?

Orang-utans belong to the genus Pongo.

Where do Orang-utans live?

Orang-utans live in Borneo and Sumatra.

In what type of habitat do Orang-utans live?

Orang-utans live in lowland tropical forests.

What are some predators of Orang-utans?

Predators of Orang-utans include humans, tigers, and clouded leopards.

How many babies do Orang-utans have?

The average number of babies an Orang-utan has is 1.

What is an interesting fact about Orang-utans?

Orang-utans share 97% of their DNA with humans!

What is the scientific name for the Orang-utan?

The scientific name for the Orang-utan is Pongo pygmaeus, Pongo abelii, or Pongo tapanuliensis.

What is the lifespan of a Orang-utan?

Orang-utans can live for 30 to 40 years.

What is a baby Orang-utan called?

A baby Orang-utan is called an infant.

How many species of Orang-utan are there?

There are 3 species of Orang-utan.

What is the biggest threat to the Orang-utan?

The biggest threats to the Orang-utan are hunting and habitat loss.

What is another name for the Orang-utan?

The Orang-utan is also called the red ape or forest person.

How many Orang-utans are left in the world?

There are 20,000 Orang-utans left in the world.

How fast is an Orang-utan?

An Orang-utan can travel at speeds of up to 2.7 miles per hour.


Video: Orangutan Longcall