Lar Gibbon
Encyclopedia
The lar gibbon also known as the white-handed gibbon, is a primate
in the Hylobatidae or gibbon
family. It is one of the better-known gibbons and is often seen in zoos.
to Thailand
and Burma down the whole Malay Peninsula
in primary and secondary tropical rain forests. It is also present in the northwest portion of the island of Sumatra
. In recent decades, especially the continental range has been reduced and fragmented, and the animals are thought to be extirpated
in China.
The gibbon genus is highly allopatric, usually separated by large rivers. The lar gibbon shares its range with only the siamang
, Symphalanges syndactylus, on the tip of the Malaysian peninsula and Sumatra.
The fur coloring of the lar gibbon varies from black and dark-brown to light brown sandy colors. The hands and feet are white colored, likewise a ring of white hair surrounds the black face. Both males and females can be all color variants, and the sexes also hardly differ in size. Gibbons are true brachiators
, propelling themselves through the forest by swinging under the branches by their arms. Reflecting this mode of locomotion, the white-handed gibbon has curved fingers, elongated hands, extremely long arms and relatively short legs, giving it an intermembral index of 129.7, one of the highest of the primates. As with all apes, the number of caudal vertebrae has been reduced drastically, resulting in the loss of a functional tail
. Gibbons have tough bony padding on their buttocks, known as the ischial callosities, or sitting pads.
is thin and light. The incisors are broad and flat, while the molars have low, rounded cusps with thick enamel
. The most noticeable characteristic of the dentition of Hylobates lar is the presence of large, dagger-like canines
in both the upper and lower jaw. These canines are not sexually dimorphic.
and arboreal, inhabiting rain forests. They rarely come to the ground, instead using their long arms to brachiate
through the trees. With their hooked hands they can move swiftly with great momentum, swinging from the branches. Although they rarely come to the ground naturally, when on the ground they walk bipedally with arms raised above the heads for balance,.Its social organization is dominated by monogamous family pairs, with one breeding male and one female along with their offspring. When a juvenile reaches sexual maturity, it is expelled from the family unit. However, this traditional conception has come under scrutiny. Long-term studies conducted in Khao Yai National Park
in Thailand suggest that their mating system is somewhat flexible, incorporating extra-pair copulations, partner changes and polyandrous groupings.
Family groups inhabit a firm territory
, which they protect by warding off other gibbons with their calls. Each morning the family gathers on the edge of its territory and begins a "great call," a duet between the breeding pair. Each species has a typified call and each breeding pair has unique variations on that theme. The great call of Hylobates lar is characterized by its frequent use of short hoots with more complex hoots, along with a "quavering" opening and closing. These calls are one of the traits used determining species differences among the gibbons.
Primate
A primate is a mammal of the order Primates , which contains prosimians and simians. Primates arose from ancestors that lived in the trees of tropical forests; many primate characteristics represent adaptations to life in this challenging three-dimensional environment...
in the Hylobatidae or gibbon
Gibbon
Gibbons are apes in the family Hylobatidae . The family is divided into four genera based on their diploid chromosome number: Hylobates , Hoolock , Nomascus , and Symphalangus . The extinct Bunopithecus sericus is a gibbon or gibbon-like ape which, until recently, was thought to be closely related...
family. It is one of the better-known gibbons and is often seen in zoos.
Range
The range of the lar gibbon historically extended from southwest ChinaChina
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
to Thailand
Thailand
Thailand , officially the Kingdom of Thailand , formerly known as Siam , is a country located at the centre of the Indochina peninsula and Southeast Asia. It is bordered to the north by Burma and Laos, to the east by Laos and Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the...
and Burma down the whole Malay Peninsula
Malay Peninsula
The Malay Peninsula or Thai-Malay Peninsula is a peninsula in Southeast Asia. The land mass runs approximately north-south and, at its terminus, is the southern-most point of the Asian mainland...
in primary and secondary tropical rain forests. It is also present in the northwest portion of 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 recent decades, especially the continental range has been reduced and fragmented, and the animals are thought to be extirpated
Local extinction
Local extinction, also known as extirpation, is the condition of a species which ceases to exist in the chosen geographic area of study, though it still exists elsewhere...
in China.
The gibbon genus is highly allopatric, usually separated by large rivers. The lar gibbon shares its range with only the siamang
Siamang
The siamang is a tailless, arboreal, black-furred gibbon native to the forests of Malaysia, Thailand, and Sumatra. The largest of the lesser apes, the siamang can be twice the size of other gibbons, reaching 1 m in height, and weighing up to 14 kg...
, Symphalanges syndactylus, on the tip of the Malaysian peninsula and Sumatra.
Appearance
Brachiation
Brachiation is a form of arboreal locomotion in which primates swing from tree limb to tree limb using only their arms.- Brachiators :...
, propelling themselves through the forest by swinging under the branches by their arms. Reflecting this mode of locomotion, the white-handed gibbon has curved fingers, elongated hands, extremely long arms and relatively short legs, giving it an intermembral index of 129.7, one of the highest of the primates. As with all apes, the number of caudal vertebrae has been reduced drastically, resulting in the loss of a functional tail
Tail
The tail is the section at the rear end of an animal's body; in general, the term refers to a distinct, flexible appendage to the torso. It is the part of the body that corresponds roughly to the sacrum and coccyx in mammals, reptiles, and birds...
. Gibbons have tough bony padding on their buttocks, known as the ischial callosities, or sitting pads.
Diet and dentition
The lar gibbon is considered frugivorous with fruit constituting 50% of its diet, but leaves (29%) are a substantial part, with insects (13%) and flowers (9%) forming the remainder . Its dental formula is 2.1.2.3/2.1.2.3, the generalized formula for Old World monkeys and apes. The dental arcade is U-shaped, and the mandibleMandible
The mandible pronunciation or inferior maxillary bone forms the lower jaw and holds the lower teeth in place...
is thin and light. The incisors are broad and flat, while the molars have low, rounded cusps with thick enamel
Tooth enamel
Tooth enamel, along with dentin, cementum, and dental pulp is one of the four major tissues that make up the tooth in vertebrates. It is the hardest and most highly mineralized substance in the human body. Tooth enamel is also found in the dermal denticles of sharks...
. The most noticeable characteristic of the dentition of Hylobates lar is the presence of large, dagger-like canines
Canine tooth
In mammalian oral anatomy, the canine teeth, also called cuspids, dogteeth, fangs, or eye teeth, are relatively long, pointed teeth...
in both the upper and lower jaw. These canines are not sexually dimorphic.
Behavior
Lar gibbons are diurnalDiurnal animal
Diurnality is a plant or animal behavior characterized by activity during the day and sleeping at night.-In animals:Animals that are not diurnal might be nocturnal or crepuscular . Many animal species are diurnal, including many mammals, insects, reptiles and birds...
and arboreal, inhabiting rain forests. They rarely come to the ground, instead using their long arms to brachiate
Brachiation
Brachiation is a form of arboreal locomotion in which primates swing from tree limb to tree limb using only their arms.- Brachiators :...
through the trees. With their hooked hands they can move swiftly with great momentum, swinging from the branches. Although they rarely come to the ground naturally, when on the ground they walk bipedally with arms raised above the heads for balance,.Its social organization is dominated by monogamous family pairs, with one breeding male and one female along with their offspring. When a juvenile reaches sexual maturity, it is expelled from the family unit. However, this traditional conception has come under scrutiny. Long-term studies conducted in Khao Yai National Park
Khao Yai National Park
Khao Yai National Park is a national park in Thailand.-Description:Khao Yai National Park is situated in the Sankamphaeng Mountain Range, the southern prolongation of the Dong Phaya Yen Mountains, at the southwestern boundary of the Khorat Plateau....
in Thailand suggest that their mating system is somewhat flexible, incorporating extra-pair copulations, partner changes and polyandrous groupings.
Family groups inhabit a firm territory
Territory (animal)
In ethology the term territory refers to any sociographical area that an animal of a particular species consistently defends against conspecifics...
, which they protect by warding off other gibbons with their calls. Each morning the family gathers on the edge of its territory and begins a "great call," a duet between the breeding pair. Each species has a typified call and each breeding pair has unique variations on that theme. The great call of Hylobates lar is characterized by its frequent use of short hoots with more complex hoots, along with a "quavering" opening and closing. These calls are one of the traits used determining species differences among the gibbons.
Reproduction
Sexually they are similar to other gibbons. Gestation is seven months long and pregnancies are usually of a single young. Young are nursed for approximately two years, and full maturity comes at about 8 years. The life expectancy of the lar gibbons in the wild is about 25 years.Status
Lar gibbons are threatened in various ways: they are sometimes hunted for their meat, sometimes a parent is killed in order to capture young animals for pets and the largest danger is the loss of habitat.Subspecies
There are five subspecies of Lar Gibbon:- Malaysian lar gibbon, Hylobates lar lar
- Carpenter's lar gibbon, Hylobates lar carpenteri
- Central lar gibbon, Hylobates lar entelloides
- Sumatran lar gibbonSumatran Lar GibbonThe Sumatran lar gibbon , also known as the Sumatran white-handed gibbon, is a subspecies of the lar gibbon, a primate in the Hylobatidae or gibbon family...
, Hylobates lar vestitus - Yunnan lar gibbonYunnan Lar GibbonThe Yunnan lar gibbon , also known as the Yunnan white-handed gibbon, is a subspecies of the lar Gibbon, a primate in the Hylobatidae or gibbon family. This Chinese subspecies is thought to be extinct.-Taxonomy:...
, Hylobates lar yunnanensis (possibly extinct)
External links
- ARKive - images and movies of the white-handed gibbon (Hylobates lar)
- Lar Gibbon photos
- Lar Gibbon songs
- Gibbon Conservation Center
- Lar Gibbon at Animal Diversity Web
- Thomas Geissmann's Gibbon Research Lab and Gibbon Network