GIBBONS IN CHINA

black-crested gibbon

Gibbons are tree-dweller apes that use their long arms to swing from tree branch to tree branch. Gibbons are known for their loud calls and mating pairs who often sing together in duet. Two species of gibbon have disappeared in China and all surviving Chinese specie are classified as Critically Endangered by the International Union for the Conservation of Nature. Hainan black crested gibbons (Nomascus hainanus, Thomas, 1892) live in Hainan Island, China. They are regarded as the world's most endangered primate.

White-cheeked gibbons (Hylobates leucogenys) have a body length of 42-52 centimeters. Their preferred habitats are low-elevation tropical forests. They pick young leaves and fruit and catch small animals with hands. They eat young leaves of trees and bushes, fruits, insects and small birds. They can be found in Xishuangbanna of Yunnan. They are regarded as an endangered species.

White-handed gibbons, or Lar gibbon, (H. lar) live in Indonesia, Laos, Malaysia, Myanmar, and Thailand. Their range historically extended from southwest China to Thailand and Burma south to the whole Malay Peninsula and into the northwest portion of the island of Sumatra.. There are five subspecies of lar gibbon: 1) Malaysian lar gibbon (H. l. lar); 2) Carpenter's lar gibbon (H. l. carpenteri); 3) Central lar gibbon (H. l. entelloides); 4) Sumatran lar gibbon (H. l. vestitus); and 5) Yunnan lar gibbon (H. l. yunnanensis). They are endangered.

About 100 Cao Vit gibbons still live along the Vietnam-China border. It was once thought to have been hunted to extinction. Concolor gibbons have had their numbers reduced by poaching and loss of habitat resulting from farming. Males are black and females are golden or tawny brown. They survive in isolated areas of Laos, Vietnam and China. There could be as few as 10,000 left. Animal behaviorist Janine Benyus wrote: "Females can be picky and, because the world's captive community is so limited, finding a compatible mate can be like dating in a very small town."

Extinct Gibbon Found in 2,300-Year-Old Chinese Tomb

A gibbon new to science was discovered buried in an ancient tomb in China, scientists reported in a study is published in the journal, Science in June 2018. Helen Briggs of the BBC wrote: “The gibbon has already become extinct, suggesting humans wiped out primate populations long before the modern age. “The new gibbon, named Junzi imperialis, may be the first to vanish as a direct result of human actions, according to scientists led by the Zoological Society of London. [Source: Helen Briggs, BBC, June 21, 2018]

The partial skull of the gibbon was found in a burial chamber dating from about 2,300 years ago in Shaanxi Province, central China, alongside the bones of other animals, including lynx, leopards and a black bear. The tomb, and perhaps the ape, may have belonged to Lady Xia, the grandmother of China's first emperor, Qin Shihuang, who ordered the building of the Great Wall of China and the Terracotta Warriors. Gibbons were seen as having noble characteristics in Chinese culture and were kept as luxury pets.

“It is almost certain that the gibbon's demise is evidence of intense human pressures on the environment during this period of history, said co-researcher Prof Helen Chatterjee of University College London. “Our historical data shows that these factors caused a southward shift of gibbons towards their present day distribution which is restricted to the very far south of China — and in the case of Junzi, its eventual extinction," she said.

Hoolock Gibbons

range of black-crested gibbons and northern white-cheeked gibbons

Hoolock gibbons (Hylobates hoolock) have a body length of 45-58 centimeters. Similar to black-crested gibbons, they live in old growth tropical forests or secondary tropical forests and pick young leaves, fruit or catch small animals with hands and eat young leaves of trees and bushes, fruits, insects and small birds. They can be found in southwest Yunnan. They are regarded as an endangered species. [Source: Center of Chinese Academy of Sciences, kepu.net]

The hoolock genus contains three species all with Hoolock in their name. Native to eastern Bangladesh, Northeast India, Myanmar, and Southwest China, they are the second-largest of the gibbons, after the siamang. They reach a size of 60 to 90 centimeters and weigh six to nine kilograms.

Western hoolock gibbons (Hoolock hoolock, Harlan, 1834) live in India, Bangladesh, and Myanmar. They are endangered.
Eastern hoolock gibbons (Hoolock leuconedys, Groves, 1967) live in China (Yunnan). They are vulnerable.
Skywalker hoolock gibbons (Hoolock tianxing, Fan et al., 2017) live in Myanmar and southwestern China. They are endangered. There are only 150 of them.

Black-Crested Gibbons

Black-crested gibbons (Nomascus concolor) are primarily found in Yunnan, China and have limited ranges in western Laos and northern Vietnam. Their distribution is fragmented. They live in evergreen, semi-evergreen, and deciduous forests in subtropical and mountainous areas and have primarily been observed at altitudes ranging from 2100 to 2400 meters (6,890 to 7,875 feet) above sea level. They have seen however at altitudes from 1600 to 2000 meters (5250 to 6,560 feet) in In Vietnam; from 550 to 900 meters (1,640 to 2,950 feet) in Laos and high as 2689 meters (8822.18 feet). Black crested gibbons are believed to have a similar lifespan in the wild as other gibbons — 25 to 30 years.

There are four subspecies: 1) Tonkin black crested gibbon (Nomascus concolor concolor), which live in an area between area the Black and Red Rivers in southern China; 2) Laotian black crested gibbon (Nomascus concolor lu), which live in northwestern Laos; 3) Central Yunnan black crested gibbon (Nomascus concolor jingdongensis, which live between the Mekong and and Chuanghe Rivers; 4) West Yunnan black crested gibbon (Nomascus concolor furvogaster), which live near the China-Myanmar border . They are critically endangered. [Source: Wikipedia]

Gibbons at Play by Zhu Zhanji-

Black crested gibbons range in weight from 6.9 to 10 kilograms (15.2 to 22 pounds) and range in length from 43 to 54 centimeters (16.93 to 21.26 inches). They don’t have a tail. Sexual Dimorphism (differences between males and females) is present: sexes colored or patterned differently Males are black, while females are tawny brown. Females have a black crown and typically have black hair grizzling or covering the lower chest and abdomen. This sexual dichromatism develops with age. The female changes from black to buff or tawny coloration in early adulthood

Black crested gibbons are folivores (eat leaves) and frugivores (eat fruits). In Yunnan, they spend roughly equal amounts of time eating leaves and fruit. Their diet varies seasonally, based on the availability of food sources including leaves, fruits, buds, and flowers. They pick young leaves and fruit and also catch small animals and insects which they eat with their hands. In a study in 2008, black crested gibbons ate increased amount of figs in August and September, flowers in February and April, leaves in March, and buds and leaves in December and January. They prefer to eat fruits and figs over other foods during their first and last meals of the day. One population of black crested gibbons observed stayed in valleys with more abundant food for several consecutive days before moving to another, in order to avoid frequent passages through areas with little food.

Black crested gibbons are considered critically endangered by the International Union for Conservation of Nature (IUCN). There could be as few as 10,000 left. On the US Federal List they are classified as Endangered. In CITES (Convention on International Trade in Endangered Species of Wild) they are in Appendix I, which lists species that are the most endangered among CITES-listed animals and plants. They survive in isolated areas and had their numbers reduced mainly because of deforestation resulting from small scale farming and development. Although now restricted, hunting and poaching once contributed considerably to the decline of these animals. It is is thought the fragmented nature of their habitat and their groups may lead to decreased gene flow, further harming the species. [Source: Clarence Cheng, Animal Diversity Web (ADW) /=]

Black Crested Gibbons Behavior, Calls and Reproduction

Black crested are arboreal (live mainly in trees), scansorial (able to or good at climbing), diurnal (active during the daytime), motile (move around as opposed to being stationary), territorial (defend an area within the home range) and social (associates with others of its species; forms social groups). The size of their range territory is 100 to 200 hectares However, one study noted that almost 70 percent of their activity took place within 29 hectares.[Source: Clarence Cheng, Animal Diversity Web (ADW) /=]

Black-crested gibbons live exclusively in trees. They move using brachiation (swinging from tree limb to tree limb using their arms). They hang from trees and swing forward through the branches, moving their two arms one after the other. Relying on the swing of the branches and the inertia of the body, they swing faster and faster and can cover a gap of 10 meters or more at one time. It is said that black-crested gibbons can catch flying birds while swinging through the trees. Though brachiation is their most common form of locomotion, they can also leap, walk, and climb. [Source: Center of Chinese Academy of Sciences, kepu.net ^^]

Black-crested gibbons spend their time in family groups consisting of a monogamous male and female pair and their offspring. Each family group occupies a piece of forest as their territory. Groups defend this territory but they retreat from human encroachment. According to Black crested gibbons prefer to sleep in tall, thick trees with large crowns, located near food. Factors that tend to affect choice of sleeping trees are height, thickness, and crown size of the tree, the accessibility of the sleeping place, and the ease of escape. Individuals may or may not reuse sleeping trees, but individuals reusing a tree often sleep in the same place on the tree. Black crested gibbons sleep by wrapping their long arms around flexed knees and leaning their heads down. /=\

Hainan gibbon from Kadoorie Farm and Botanic Garden, Hong Kong

Black-crested gibbons sense using vision, touch, sound and chemicals usually detected with smell and communicate with vision, touch and sound. They also employ duets (joint displays, usually between mates, and usually with highly-coordinated sounds) to communicate. Females make very long and loud cries each morning. The male responds and the male and female cry out in antiphonal style and sing in choruses. After a period of time, young apes also join the chorus. These calls last 10 minutes or more. The cries are quite touching and can be heard kilometers away. The songs of black crested gibbons may be used for a variety of purposes, including: 1) defense of resources; 2) establishment of territories; 3) attracting mates; and 4) strengthening pair bonds. These gibbons sing both alone and in pairs. Duets are usually initiated by males from high locations, such as tall trees on hills. The calls may help gibbons define their territory and warn nearby gibbon groups ot stay away but in the past the cries also exposed them to hunters who killed them.

Black crested gibbons are mostly monogamous (have one mate at a time) but can be polygynous (males have more than one female as a mate at one time). Sometimes two females in a single breeding group are tolerated. Polygyny has not been observed in other species of gibbons. Animal behaviorist Janine Benyus wrote: "Females can be picky and, because the world's captive community is so limited, finding a compatible mate can be like dating in a very small town." Singing may play a role in mate attraction, pair-bonding, and mate defense.

Black crested gibbons reproduce once every two to three years, with the average number of offspring being one. The gestation period ranges from seven to eight months. On average males and females reach sexual or reproductive maturity at eight years. Newborns weigh about about half a kilograms at birth. They are nursed by their mother until about two years of age. Males and older offspring also provide care to young.

Hainan Gibbons: the World's Rarest Primate

Hainan gibbons, or Hainan black-crested gibbons (Nomascus hainanus) are critically endangered and found only on Hainan Island, China. They were formerly considered a subspecies of the eastern black crested gibbon from Hòa Bình and Cao Bang provinces of Vietnam and Jingxi County in Guangxi Zhuang Autonomous Region, China but is now regarded as separate species based on molecular data and morphology and. They live in broad-leaved forests and semi-deciduous monsoon forests and feeds on ripe, sugar-rich fruit, such as figs and, at times, leaves, and insects. Once common across China, the apes are now confined to a patch of forest on Hainan island, which is in the South China Sea. [Source: Wikipedia]

Hainan gibbons are regarded as the world's rarest primate. A count done in the 2010s found 22 of them split between two families, one of 11 and one of seven members, with four loners, all residing in 300-square-kilometer Bawangling National Nature Reserve (BNNR) on Hainan Island.
Hainan gibbons live in tropical areas in rainforests and mountains at elevations of 100 to 1800 meters (328 to 5905 feet), favoring the canopies of ravine tropical forests. Their entire population is found in Historically, Hainan gibbons were widespread on Hainan Island but it has been estimated that 95 percent of their original habitat has been lost. Hainan gibbons require indigenous forest and have not inhabited recently planted pine forests or rubber plantations. Due to habitat loss and hunting, they have shifted their main habitat from lowland forest to higher mountainous forests. [Source: Rob Gregoire, Animal Diversity Web (ADW) /=]

Hainan gibbon range

Hainan gibbons range in weight from 5.8 to 10 kilograms (12.8 to 22 pounds). Most likely their body length is similar to that of other gibbons such as the white-handed gibbon which is 42 to 60 centimeters (16.5 to 23.6 inches) in length. The hind limbs of Hainan gibbons are 70.4 percent the length of forelimbs, which is slightly longer than in other black-crested gibbons. Sexual Dimorphism (differences between males and females) is present: sexes are colored or patterned differently but are about the same size. Adult males and juveniles are black while females are brownish buff with some black hairs appearing on the limbs as they age. Males and females have a large black crest of fur on the top of their heads. The crest is approximately ten by three centimeters. Females also have a characteristic white face ring. Infants are born tawny brown, becoming black within five to six months. [Source: Rob Gregoire, Animal Diversity Web (ADW) /=]

Hainan gibbons are almost exclusively frugivores (eat mainly fruits). In the reserve they inhabit, they mostly eat the fruits from Litchi canensis, Nephelium topengii, and various Ficus species. Figs in particular are favored food source. Closely related species of gibbons eat insects, seeds, and grains and Hainan gibbons may do the same

Hainan Gibbon Behavior and Communication

Hainan gibbons are arboreal (live mainly in trees), scansorial (able to or good at climbing), diurnal (active during the daytime), motile (move around as opposed to being stationary), sedentary (remain in the same area), (associates with others of its species; forms social groups), and have dominance hierarchies (ranking systems or pecking orders among members of a long-term social group, where dominance status affects access to resources or mates). Hainan gibbons individuals occupy home ranges of 200 to 500 hectares (two to five square kilometers), which are the largest home range sizes of any gibbon. According to Animal Diversity: However, this large size might be the result of reduced intraspecific competition or increased area between suitable food patches. It is suggested that home range size might recently have increased to nearly 1000 hectares (10 square kilometers) due to degradation of habitat quality.[Source: Rob Gregoire, Animal Diversity Web (ADW) /=]

Hainan gibbons are found in social groups composed of females, juveniles, infants and, occasionally, males. Males will also live solitarily. Group size has been hard to determine due to the extremely low population size and fluctuations in behavior of Hainan gibbons as a result of the degradation of habitat. The most common form of locomotion is brachiation (swinging from tree limb to tree limb using their arms). Leaping, walking and climbing have been observed but the gibbons have never been seen coming to the ground.

Hainan gibbons sense and communicate using vision, touch, sound and chemicals usually detected with smell. They also employ duets (joint displays, usually between mates, and usually with highly-coordinated sounds) to communicate. Males and females perform morning duets. The female usually only emits a single loud noise often referred to as a great-call. The male’s song is more elaborate and has at least three distinct calls. The presence of a laryngeal sac in males may contribute to the increased complexity of vocalizations. Hainan gibbons are believed to be the only gibbon species with a male dominated duet. Hainan gibbons are one of only three gibbon species in which the female makes vocalizations during mating. There are many hypotheses concerning these soft grunts of the female but it might have be related to the social polygyny of Hainan gibbons and it may be an advertisement of ovulation to other females.

Hainan Gibbon Reproduction and Offspring

Hainan gibbons are polygynous (males have more than one female as a mate at one time). Two females and a single male, is the usual mating system. According to Animal Diversity Web: Females initiate mating by approaching a male and moving their head and limbs in rhythmic, jerky motions. Multiple copulations may occur in a single day. Sexually active females occasionally engage in post-conception copulation, which is relatively rare among the primates. [Source: Rob Gregoire, Animal Diversity Web (ADW) /=]

Hainan gibbons females give birth every two years. The amount of time between births may be related to the biannual fruiting of many favored food sources. No breeding season has been reported. The average number of offspring being one. The gestation period ranges from 136 to 173 days. Infants are dependent on their mother for the first 1.5 years of their lives, but remain in the social group as juveniles for some time after this. Two females in a single social group may rear offspring from the same male at the same time.

When members of the group reach sexual maturity they are forced out of the group. In one case, a maturing male offspring was driven out of the group at 5.5 years of age. This is quite early compared to most other gibbon species, which mature from six to nine years. A possible reason for this eviction, besides actual sexual maturity is that, due to limited resources, the alpha male may have been forced to drive out the maturing offspring.

Hainan Gibbon Conservation

Some have suggested that Hainan gibbons are the rarest mammals in the world, with approximately 20 individuals. One survey found only four are adult females and one of these may be too old to bear offspring. Numbers have increased since 2003, when it was believed that there were as few as 13 individuals. On the International Union for Conservation of Nature (IUCN) Red List they are listed as Critically Endangered. In CITES (Convention on International Trade in Endangered Species of Wild) they are in Appendix I, which lists species that are the most endangered among CITES-listed animals and plants. [Source: Rob Gregoire, Animal Diversity Web (ADW) /=]

Humans are the main predators of Hainan gibbons. They have sold gibbons into the illegal animal trade, use their meat for food, sold their bones for use in traditional Chinese medicine and killed them for being crop pests. Mass slaughters have been recorded on several occasions. Two attacks from an unidentified species of hawk lasting approximately 15 minutes have been observed on Hainan gibbons.

Rob Gregoire wrote in Animal Diversity Web: Habitat loss and human encroachment and activity are the main reasons for the decline in population of Hainan gibbons. The species has seen a drastic reduction in range and population since the 1950s. The annual rate of habitat loss is approaching zero... but Hainan gibbons are, without a doubt, on the very edge of extinction. Due to the critically endangered status of Hainan gibbons, the Chinese government has put a ban on all types of forestry in or around BNNR. Hainan Island, which is home to many introduced rubber plantations, has been forced to stop the expansion of the rubber industry in order to save Hainan gibbons and other endangered species. This is a short-term negative economic impact, but has long-term positive impacts because it helps to protect a critical and unique ecosystem. Conservation efforts are varied. Technologies such as remote sensing and geographic information systems are being used to determine suitable habitats. The government is also planning on adding to the list of protected forest on Hainan Island. In 2003, the Hainan Gibbon Action Plan was launched. Population surveys, reforestation, and the training of staff to monitor the gibbons are all parts of the Action Plan.

According to the BBC: “A conservation programme run by the Kadoorie Farm and Botanic Garden in Hong Kong is trying to rescue the species from extinction. “When we started work at the reserve, in 2003, we could only find two groups with a total of 13 individuals were left in the entire world," “Dr Bosco Chan told BBC News. “The gibbon population has gradually recovered, with a third and fourth family group formed in 2011 and 2015, respectively. “At the beginning of 2020, we confirmed the formation of the fifth group, and the world population has bounced back to over 30 individuals. It shows the species is slowly recovering, and we should have hope." [Source: Helen Briggs, BBC, October 16, 2020]

“Reforestation should be the priority in preventing extinction of the species, he added. “We need to make sure we control poaching effectively, expand lowland forest which is the optimal habitat for gibbons, and keep monitoring the gibbon groups to predict and prevent any threats. " Within their habitat, they travel above ground from tree to tree. Gaps in the canopy, both natural and man-made, can tie them to a specific area, interfering with foraging and breeding, and increasing the risk of predation. In 2020 a landslide tore a huge gap in the forest, making it difficult for the gibbons to roam around and a rope bridge was built reconnecting the trees.

Image Sources: Wikimedia Commons

Text Sources: Animal Diversity Web animaldiversity.org ; National Geographic, Live Science, Natural History magazine, David Attenborough books, New York Times, Washington Post, Los Angeles Times, Smithsonian magazine, Discover magazine, The New Yorker, Time, Reuters, Associated Press, AFP, Lonely Planet Guides, Wikipedia, The Guardian, Top Secret Animal Attack Files website and various books and other publications.

Last updated December 2024