Sumatran Orangutan
Encyclopedia
The Sumatran orangutan is one of the two species of orangutan
s. Found only on the island of Sumatra
, in Indonesia
, it is rarer and smaller than the Bornean orangutan
. The Sumatran orangutan grows to about 1.4 metres (4.6 ft) tall and 90 kilograms (198.4 lb) in males. Females are smaller
, averaging 90 centimetres (3 ft) and 45 kilograms (99.2 lb).
s and jackfruit
s. It will also eat bird egg
s and small vertebrate
s. Sumatran orangutans spend far less time feeding on the inner bark of trees.
Wild Sumatran orangutans in the Suaq Balimbing swamp
have been observed using tools
. An orangutan will break off a tree branch that is about a foot long, snap off the twigs and fray one end. It then will use the stick to dig in tree holes for termite
s. They will also use the stick to poke a bee's nest wall, move it around and catch the honey. In addition, orangutans use tools to eat fruit. When the fruit of the Neesia tree ripens, its hard, ridged husk softens until it falls open. Inside are seed
s that the orangutans enjoy eating, but they are surrounded by fiberglass-like hairs that are painful if eaten. A Neesia-eating orangutan will select a five-inch stick, strip off its bark, and then carefully collect the hairs with it. Once the fruit is safe, the ape will eat the seeds using the stick or its fingers. Although similar swamps can be found in Borneo, wild Bornean orangutans have not been seen using these types of tools.
NHNZ filmed the Sumatran orangutan for its show Wild Asia: In the Realm of the Red Ape; it showed one of them using a simple tool, a twig, to pry food from difficult places. There is also a sequence of an animal using a large leaf as an umbrella in a tropical rainstorm.
The Sumatran orangutan is also more arboreal than its Bornean cousin; this could be because of the presence of large predators like the Sumatran Tiger
. It moves through the trees by quadrumanous locomotion and semibrachiation
.
The average interbirth rates for the Sumatran orangutan is 9.3 years – the longest reported among the great apes, including the Bornean orangutan. Infant orangutans will stay close to their mother for up to three years. Even after that, the young will still associate with their mother. Both orangutan species are likely to live several decades; estimated longevity is more than 50 years. The average of the first reproduction of P. abelii is around 15.4 years old. There is no indication of menopause
.
The Sumatran orangutan is endemic to Sumatra island and is particularly restricted to the north of the island. In the wild, Sumatran orangutans survive in the province of Nanggroe Aceh Darussalam (NAD), the northernmost tip of Sumatra. The primate was once more widespread, as they were found more to the south in the 19th century such as in Jambi and Padang
.
There are small populations in the North Sumatra
province along the border with NAD, particularly in the Lake Toba
forests. A survey in the Lake Toba region found only two inhabited areas, Bukit Lawang
(defined as the animal sanctuary
) and Gunung Leuser National Park
. The species has been assessed as critically endangered on the IUCN Red List
since 2000. It is considered one of "The World's 25 Most Endangered Primates
."
A survey in 2004 estimated that around 7,300 Sumatran orangutans still live in the wild. Some of them are being protected in five areas in Gunung Leuser National Park; others live in unprotected areas: northwest and northeast Aceh block, West Batang Toru river, East Sarulla and Sidiangkat. A successful breeding program has been established in Bukit Tiga Puluh National Park in Jambi and Riau provinces.
Nonja, thought to be the world's oldest in captivity or the wild at the time of her death, died at the Miami MetroZoo at the age of 55.
s. The Sumatran orangutan genome was sequenced in , based on a captive female named Susie. Following humans and chimpanzee
s, the Sumatran Orangutan has become the third extant hominid species to have its genome sequenced.
The researchers also published less complete copies from ten wild orangutans, five from Borneo
and five from Sumatra
. It was found that genetic diversity
was lower in Bornean Orangutans (Pongo pygmaeus) than in Sumatran ones (Pongo abelii), despite the fact that Borneo is home to six or seven times as many orangutans as Sumatra. The comparison has shown that these two species diverged around 400,000 years ago, more recently than was previously thought. It was also found that the orangutan genome has fewer rearrangements
than the chimpanzee/human lineage.
Orangutan
Orangutans are the only exclusively Asian genus of extant great ape. The largest living arboreal animals, they have proportionally longer arms than the other, more terrestrial, great apes. They are among the most intelligent primates and use a variety of sophisticated tools, also making sleeping...
s. Found only on the island of Sumatra
Sumatra
Sumatra is an island in western Indonesia, westernmost of the Sunda Islands. It is the largest island entirely in Indonesia , and the sixth largest island in the world at 473,481 km2 with a population of 50,365,538...
, in Indonesia
Indonesia
Indonesia , officially the Republic of Indonesia , is a country in Southeast Asia and Oceania. Indonesia is an archipelago comprising approximately 13,000 islands. It has 33 provinces with over 238 million people, and is the world's fourth most populous country. Indonesia is a republic, with an...
, it is rarer and smaller than the Bornean orangutan
Bornean Orangutan
The Bornean orangutan, Pongo pygmaeus, is a species of orangutan native to the island of Borneo. Together with the slightly smaller Sumatran orangutan, it belongs to the only genus of great apes native to Asia....
. The Sumatran orangutan grows to about 1.4 metres (4.6 ft) tall and 90 kilograms (198.4 lb) in males. Females are smaller
Sexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
, averaging 90 centimetres (3 ft) and 45 kilograms (99.2 lb).
Behaviour
Compared with the Bornean orangutan, the Sumatran orangutan tends to be more frugivorous and especially insectivorous. Preferred fruits include figFicus
Ficus is a genus of about 850 species of woody trees, shrubs, vines, epiphytes, and hemiepiphyte in the family Moraceae. Collectively known as fig trees or figs, they are native throughout the tropics with a few species extending into the semi-warm temperate zone. The Common Fig Ficus is a genus of...
s and jackfruit
Jackfruit
The jackfruit is a species of tree in the Artocarpus genus of the mulberry family . It is native to parts of Southern and Southeast Asia. It is the national fruit of Bangladesh, . The jackfruit tree is believed to be indigenous to the southwestern rain forests of India...
s. It will also eat bird egg
Bird egg
Bird eggs are laid by females and incubated for a time that varies according to the species; a single young hatches from each egg. Average clutch sizes range from one to about 17...
s and small vertebrate
Vertebrate
Vertebrates are animals that are members of the subphylum Vertebrata . Vertebrates are the largest group of chordates, with currently about 58,000 species described. Vertebrates include the jawless fishes, bony fishes, sharks and rays, amphibians, reptiles, mammals, and birds...
s. Sumatran orangutans spend far less time feeding on the inner bark of trees.
Wild Sumatran orangutans in the Suaq Balimbing swamp
Swamp
A swamp is a wetland with some flooding of large areas of land by shallow bodies of water. A swamp generally has a large number of hammocks, or dry-land protrusions, covered by aquatic vegetation, or vegetation that tolerates periodical inundation. The two main types of swamp are "true" or swamp...
have been observed using tools
Tool use by animals
Tools are used by some animals, particularly primates, to perform simple tasks such as the acquisition of food, or grooming. Originally thought to be a skill only possessed by humans, tool use requires some level of intelligence. Primates have been observed exploiting sticks and stones to...
. An orangutan will break off a tree branch that is about a foot long, snap off the twigs and fray one end. It then will use the stick to dig in tree holes for termite
Termite
Termites are a group of eusocial insects that, until recently, were classified at the taxonomic rank of order Isoptera , but are now accepted as the epifamily Termitoidae, of the cockroach order Blattodea...
s. They will also use the stick to poke a bee's nest wall, move it around and catch the honey. In addition, orangutans use tools to eat fruit. When the fruit of the Neesia tree ripens, its hard, ridged husk softens until it falls open. Inside are seed
Seed
A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...
s that the orangutans enjoy eating, but they are surrounded by fiberglass-like hairs that are painful if eaten. A Neesia-eating orangutan will select a five-inch stick, strip off its bark, and then carefully collect the hairs with it. Once the fruit is safe, the ape will eat the seeds using the stick or its fingers. Although similar swamps can be found in Borneo, wild Bornean orangutans have not been seen using these types of tools.
NHNZ filmed the Sumatran orangutan for its show Wild Asia: In the Realm of the Red Ape; it showed one of them using a simple tool, a twig, to pry food from difficult places. There is also a sequence of an animal using a large leaf as an umbrella in a tropical rainstorm.
The Sumatran orangutan is also more arboreal than its Bornean cousin; this could be because of the presence of large predators like the Sumatran Tiger
Sumatran Tiger
The Sumatran tiger is a tiger subspecies that inhabits the Indonesian island of Sumatra and has been classified as critically endangered by IUCN in 2008 as the population is projected at 176 to 271 mature individuals, with no subpopulation having an effective population size larger than 50...
. It moves through the trees by quadrumanous locomotion and semibrachiation
Brachiation
Brachiation is a form of arboreal locomotion in which primates swing from tree limb to tree limb using only their arms.- Brachiators :...
.
Life cycle
The Sumatran orangutan is more social than its Bornean counterpart. Groups of these orangutans gather to feed on the mass amount of fruiting on the fig trees. However adult males generally avoid contact with other adult males. Sub-adult males will try to mate with any female, though they probably mostly fail to impregnate them since mature females are easily capable of fending them off. Mature females prefer to mate with mature males.The average interbirth rates for the Sumatran orangutan is 9.3 years – the longest reported among the great apes, including the Bornean orangutan. Infant orangutans will stay close to their mother for up to three years. Even after that, the young will still associate with their mother. Both orangutan species are likely to live several decades; estimated longevity is more than 50 years. The average of the first reproduction of P. abelii is around 15.4 years old. There is no indication of menopause
Menopause
Menopause is a term used to describe the permanent cessation of the primary functions of the human ovaries: the ripening and release of ova and the release of hormones that cause both the creation of the uterine lining and the subsequent shedding of the uterine lining...
.
Conservation status
Padang, Indonesia
Padang is the capital and largest city of West Sumatra, Indonesia. It is located on the western coast of Sumatra at . It has an area of and a population of over 833,000 people at the 2010 Census.-History:...
.
There are small populations in the North Sumatra
North Sumatra
North Sumatra is a province of Indonesia on the Sumatra island. Its capital is Medan. It is the most populous Indonesian province outside of Java. It is slightly larger than Sri Lanka in area.- Geography and population :...
province along the border with NAD, particularly in the Lake Toba
Lake Toba
Lake Toba is a lake and supervolcano. The lake is 100 kilometres long and 30 kilometres wide, and 505 metres at its deepest point. Located in the middle of the northern part of the Indonesian island of Sumatra with a surface elevation of about , the lake stretches from to...
forests. A survey in the Lake Toba region found only two inhabited areas, Bukit Lawang
Bukit Lawang
Bukit Lawang is a small tourist village at the bank of Bahorok River in North Sumatra province of Indonesia. Situated approximately 86 km north-west of Medan, Bukit Lawang is known for the largest animal sanctuary of Sumatran orangutan , and also the main access point to the Gunung Leuser National...
(defined as the animal sanctuary
Animal sanctuary
An animal sanctuary is a facility where animals are brought to live and be protected for the rest of their lives. Unlike animal shelters, sanctuaries do not seek to place animals with individuals or groups, instead maintaining each animal until his or her natural death...
) and Gunung Leuser National Park
Gunung Leuser National Park
Gunung Leuser National Park is a national park covering 7,927 km² in northern Sumatra, Indonesia, straddling the border of North Sumatra and Aceh provinces. The national park, named after Mount Leuser , protects a wide range of ecosystems. An orangutan sanctuary of Bukit Lawang is located inside...
. The species has been assessed as critically endangered on the IUCN Red List
IUCN Red List
The IUCN Red List of Threatened Species , founded in 1963, is the world's most comprehensive inventory of the global conservation status of biological species. The International Union for Conservation of Nature is the world's main authority on the conservation status of species...
since 2000. It is considered one of "The World's 25 Most Endangered Primates
The World's 25 Most Endangered Primates
The World's 25 Most Endangered Primates is a list of highly endangered primate species selected and published by the International Union for Conservation of Nature Species Survival Commission Primate Specialist Group , the International Primatological Society , and Conservation International...
."
A survey in 2004 estimated that around 7,300 Sumatran orangutans still live in the wild. Some of them are being protected in five areas in Gunung Leuser National Park; others live in unprotected areas: northwest and northeast Aceh block, West Batang Toru river, East Sarulla and Sidiangkat. A successful breeding program has been established in Bukit Tiga Puluh National Park in Jambi and Riau provinces.
Nonja, thought to be the world's oldest in captivity or the wild at the time of her death, died at the Miami MetroZoo at the age of 55.
Genomics
Orangutans have 48 chromosomeChromosome
A chromosome is an organized structure of DNA and protein found in cells. It is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences. Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions.Chromosomes...
s. The Sumatran orangutan genome was sequenced in , based on a captive female named Susie. Following humans and chimpanzee
Chimpanzee
Chimpanzee, sometimes colloquially chimp, is the common name for the two extant species of ape in the genus Pan. The Congo River forms the boundary between the native habitat of the two species:...
s, the Sumatran Orangutan has become the third extant hominid species to have its genome sequenced.
The researchers also published less complete copies from ten wild orangutans, five from Borneo
Borneo
Borneo is the third largest island in the world and is located north of Java Island, Indonesia, at the geographic centre of Maritime Southeast Asia....
and five from Sumatra
Sumatra
Sumatra is an island in western Indonesia, westernmost of the Sunda Islands. It is the largest island entirely in Indonesia , and the sixth largest island in the world at 473,481 km2 with a population of 50,365,538...
. It was found that genetic diversity
Genetic diversity
Genetic diversity, the level of biodiversity, refers to the total number of genetic characteristics in the genetic makeup of a species. It is distinguished from genetic variability, which describes the tendency of genetic characteristics to vary....
was lower in Bornean Orangutans (Pongo pygmaeus) than in Sumatran ones (Pongo abelii), despite the fact that Borneo is home to six or seven times as many orangutans as Sumatra. The comparison has shown that these two species diverged around 400,000 years ago, more recently than was previously thought. It was also found that the orangutan genome has fewer rearrangements
Structural variation
Structural variation is the variation in structure of an organism's chromosome. It consists of many kinds of variation in the genome of one species, and usually includes microscopic and submicroscopic types, such as deletions, duplications, copy-number variants, insertions, inversions and...
than the chimpanzee/human lineage.