Gibbon

Gibbons belong to the Hylobatidae family of apes. Gibbon animals are acrobatic creatures that are unique to the dense forests of southern Asia. They have evolved to live in the trees and very seldom descend to the ground. Gibbon monkeys are found in over a dozen different species, from northeastern India to southern China to Borneo. Their lengthy coats range in colour from cream to brown to black, and they are all tailless. On their faces, hands, and feet, many have white marks. The largest species, called siamangs, can weigh up to 29 pounds. Smaller species can weigh as little as nine pounds.

Taxonomy of Gibbon Animals

Here let us look at the scientific classification of gibbon monkeys.

• Gibbons belong to the kingdom Animalia.

• The phylum of the gibbon ape is Chordata.

• Gibbons belong to the class Mammalia.

• Their order is Primates and the suborder is Haplorhini.

• Their infraorder is Simiiformes.

• Their parvorder is Catarrhini.

• The superfamily of gibbons is Hominoidea.

• Their family is Hylobatidae.

• There are seven genera and 18 species of gibbon apes. Three of the seven genera are extinct. The seven genera are as follows: 

• Hylobates

• Hoolock

• Nomascus

• Symphalangus

• Bunopithecus

• Junzi

• Kapi

• The species of the genera Bunopithecus, Junzi, and Kapi are extinct.

Physical Appearance of Gibbon

• Gibbons are extremely small and light. They have a small, round head, long arms (longer than legs), and a short, slender torso. Gibbons' bones are quite light. They lack a tail, like all apes.

• Except for their cheeks, fingers, palms, armpits, and bottoms of their feet, gibbons are covered in light-coloured to very dark brown or black dense hair over the majority of their bodies. Some gibbon species have a white face ring, which is a band of white skin that completely surrounds their face.

• Hearing, sight, including colour vision, smell, taste, and touch are all senses that gibbons have in common with humans.

• Gibbons have a hairless face, tiny nostrils, and jet-black skin.

• Gibbon’s hands have four long fingers and a smaller opposable thumb, just like humans. Their feet have five toes, one of which is opposable. Gibbons can use both their hands and their feet to hold and carry objects. They utilise four fingers of their hands as a hook when brachiating through the trees. They do not utilise their thumbs for this.

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Behaviour of Gibbon Animals

• Gibbon apes dwell in the rainforest canopy for most of their life. They are the world's best brachiators because of their extended reach and muscular legs.

• They can leap up to 50 feet in a single leap, allowing them to travel swiftly. They may miss a branch or misjudge the distance between trees, resulting in fractured bones.

• They only go down to the forest floor on rare occasions. Perhaps they're in the treetops looking for food or fleeing from another animal.

• These apes walk on two feet when on the ground, holding their arms over their heads to maintain an erection.

• Gibbons of all kinds are vocal. Their vocals are musical and have the ability to travel long distances. They utilise sound to find other gibbons, warn off intruders, and attract mates. The great call is a wooing song that is often performed in a duet with the chosen mate.

• The throat sacs of Siamang gibbons and other species are unusually developed. When the animal inhales, filling the throat sac with air, it amplifies its sound, which aids in locating other apes, marking territorial borders, or joining in a mating duet in the tropical forest. The siamang, the largest species, has a booming voice that may carry up to two kilometres.

• These primates are a general mate for life. They live in small nuclear families with one juvenile child and a mated pair. These animals do not make nests like other apes, despite sleeping in the trees. When the young one reaches adulthood, it forms its own family group.

Classification of Gibbon Species

There are four extant genera of gibbon animals that will be discussed in this section:

Genus Hoolock

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• Hoolock gibbons are three primate species belonging to the genus Hoolock in the Hylobatidae family of gibbons that are native to eastern Bangladesh, northeast India, Myanmar, and southwest China.

• The hoolock gibbon is the second-largest gibbon after the siamang.

• They grow to be 60 to 90 cm long and weigh 6 to 9 kg. Females have grey-brown fur that is heavier towards the chest and neck, whilst males have black hair with notable white brows.

• Their faces have white rings around their eyes and mouths, giving them a mask-like look.

• They are diurnal and arboreal, like the other gibbons, brachiating through the trees with their long arms.

• They live in monogamous pairs that have established a territory. They use their sounds to find family members and keep other gibbons out of their territory.

• Fruits, insects, and leaves make up the majority of their diet.

• Young hoolocks are born with milky white or buff-coloured hair after a 7-month gestation period.

• Males hair darkens and goes black after around 6 months, while females hair remains buff-coloured throughout their lives.

• They are totally mature after 8-9 years, and their fur has reached its ultimate colouring.

• In the wild, they have a 25-year life expectancy.

• The hoolock is found in northeast India, south of the Brahmaputra and North Bank areas, and east of the Dibang Rivers. Arunachal Pradesh, Assam, Manipur, Meghalaya, Mizoram, Nagaland, and Tripura are among the states where it can be found.

• There are 3 hoolock species:

• Western hoolock gibbon (Hoolock hoolock)

• Eastern hoolock gibbon (Hoolock leuconedys)

• Skywalker hoolock gibbon (Hoolock tianxing)

Genus Hylobates

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• The Hylobates genus is one of the four gibbon genera. Its name comes from the Greek term for "forest walker."

• It was once thought to be the only genus, but its subgenera have lately been upgraded to genus status.

• Hylobates is the gibbon genus with the most species and range, spreading from southern China to western and central Java.

• Individuals belonging to this species have 44 chromosomes and frequently have a ring of white fur around their faces.

• The species of genus Hylobates are:

• Malaysian lar gibbon (Hylobates lar lar)

• Carpenter's lar gibbon (Hylobates lar carpenteri)

• Central lar gibbon, (Hylobates lar entelloides)

• Sumatran lar gibbon (Hylobates lar vestitus)

• Yunnan lar gibbon (Hylobates lar yunnanensis)

• Bornean white-bearded gibbon (Hylobates albibarbis)

• Agile gibbon or black-handed gibbon (Hylobates agilis)

• Muller's gray gibbon (Hylobates muelleri muelleri)

• Abbott's gray gibbon (Hylobates muelleri abbotti)

• Northern gray gibbon (Hylobates muelleri funereus)

• Western silvery gibbon or western Javan gibbon (Hylobates moloch moloch)

• Eastern silvery gibbon or central Javan gibbon (Hylobates moloch pongoalsoni)

• Pileated gibbon or capped gibbon (Hylobates pileatus)

• Kloss's gibbon or Mentawai gibbon or bilou (Hylobates klossii)

Genus Symphalangus

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• Siamang (Symphalangus syndactylus) is the only species that belongs to the genus Symphalangus which is the largest gibbon animal.

• The siamang is a black-furred arboreal gibbon that can be found in the woods of Indonesia, Malaysia, and Thailand. The siamang, the largest of the gibbons, can grow to be double the size of other gibbons, standing up to 1 m tall and weighing up to 14 kg.

• The siamang has the darkest tint of all gibbons, with long, dense, shaggy hair. The long, gangly arms of the ape are longer than its legs. A siamang's usual length is 90 cm, although the longest one ever recorded was 1 m 50 cm. Apart from a small moustache, this huge gibbon's face is mostly hairless.

• The siamang lives in the forest remnants of Sumatra Island and the Malay Peninsula and can be found at altitudes of up to 3800 metres. Its habitat ranges from lowland woodland to mountain forest and even rainforest.

• The siamang lives in groups of up to six individuals, with a home range of 23 hectares on average.

• Their day ranges are often less than 1 km, which is significantly lower than sympatric Hylobates species.

• After the agile gibbons or lar gibbons calls, the siamang's melodic singing disrupts the forest's silence in the early morning.

• Although the siamangs of Sumatra and the Malay Peninsula have similar appearances, they have different behaviours.

• The siamang primarily consumes plant parts. Fruit makes up to 60% of the Sumatran siamang's diet, making it more frugivorous than its Malayan cousin. The siamang consumes at least 160 different plant species, ranging from vines to woody plants. Figs are its primary food source. The siamang prefers ripe fruit over unripe fruit, as well as fresh leaves over old ones. Flowers and a few creatures, usually insects, are among its favourite foods.

• An adult dominant male, an adult dominant female, offspring, newborns, and occasionally a subadult make up a group of siamangs. After reaching the age of 6–8 years, the subadult usually departs the group. Subadult females are more likely to abandon the group than subadult males.

• The gestation period in Siamang is between 6.2 and 7.9 months, and the newborn is cared for by the mother for the first year of its life.

• In comparison to other gibbon species, Siamangs are known to have monogamous mating pairs that have been reported to spend more time in close contact with each other.

• From dawn to dark, the siamang spends more than half of its awake time sleeping, followed by feeding, moving, foraging, and social activities.

• It takes more time to rest in the middle of the day, allowing time to groom others or play. It normally lies on its back or stomach on a branch of a huge tree when resting.

• Feeding, foraging, and movement occur most frequently in the morning and after a period of rest.

• One of the most crucial social interactions among family members is grooming. The adults groom the juveniles earlier in the day, and the youngsters groom the adults later in the day. Grooming is most prevalent among adult males.

• Siamangs are highly sociable primates who use a wide range of tactile and visual signals, as well as behaviours and facial expressions, to communicate and strengthen social relationships within their family group. They are extremely territorial, and they communicate with other family groups by emitting loud sounds to alert them to the location of their territory.

• The siamang begins its day by calling early in the morning; after midday, it calls less frequently, with the peak of calls occurring between 9:00 and 10:00 a.m. The siamang's calls are mostly intended at its neighbours, not those within its home range.

• Habitat loss due to plantations, forest fires, illicit logging, encroachment, and human activity is a major danger to the siamang. 

• For instance, in the last four decades, palm oil plantations have wiped out significant swaths of the siamang's habitat. 

• Illegal logging has damaged forests in the Malay Peninsula, with 16 of Malaysia's 37 permanent forest reserves encroached upon by illegal loggers, including the area where the majority of the siamangs live. 

• The forest encroachments convert forest area to arable land. 

• The development in many areas necessitates infrastructure, such as highways, which have generated forest fragmentation and edge effects by dividing conservation areas.

• Primates are not hunted for their meat in Indonesia, unlike in other regions of Asia. They are hunted for the illegal pet trade, with infant siamangs being preferred by hunters. Because siamang females are very protective of their infants, poachers frequently murder the mothers first, making it difficult to remove the infant without first killing the mother. The majority of siamangs on the market are newborns, who frequently die during shipping.

Genus Nomascus

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• Gibbons which belong to the genus Nomascus is the second most diverse gibbon species.

• Originally, this genus was considered a subgenus of Hylobates, with Hylobates concolor as the sole species.

• Nomascus species are distinguished by their 52 chromosomes.

• Some species are completely black, while others are pale with a conspicuous black tuft of head hair and light-coloured cheek patches.

• Nomascus can be found from Yunnan, China, to southern Vietnam, as well as on Hainan Island.

• Nomascus nasutus has been designated as the world's most critically endangered ape species. This genus contains only endangered or highly endangered species.

• The species of genus Nomascus are:

• Tonkin black crested gibbon (Nomascus concolor concolor)

• Laotian black crested gibbon (Nomascus concolor lu)

• Central Yunnan black crested gibbon (Nomascus concolor jingdongensis)

• West Yunnan black crested gibbon (Nomascus concolor furvogaster)

• Eastern black crested gibbon (Nomascus nasutus)

• Hainan black-crested gibbon (Nomascus hainanus)

• Northern white-cheeked gibbon (Nomascus leucogenys)

• Southern white-cheeked gibbon (Nomascus siki)

• Yellow-cheeked gibbon (Nomascus gabriellae)

• Northern buffed-cheeked gibbon (Nomascus annamensis)

Habitat of Gibbon Animals

Gibbon animals usually inhabit the rain forests of Southeast Asia as in dense forest canopy which provides food, shelter, and a mode of transit for these arboreal species. Although different species reside in diverse environments, such as mountains or valleys, they always favour treetop habitats. 

Gibbons are found in the following countries:

• Bangladesh

• Borneo

• Cambodia

• China

• India

• Indonesia

• Java

• Laos

• Malaysia

• Myanmar

• Sumatra

• Thailand

• Vietnam

Reproduction and Lifespan of Gibbons

• The female gibbon delivers one offspring at a time. During their breeding period, they may have up to six babies.

• Wild females reach the age of eight years while males mature a little later, about 10 years.

• These arboreal mammals take one mate, but when their offspring grow up, they can become partners.

• Six-and-a-half months in female pregnancy. After birth, the baby is cared for until both parents are old enough to leave home.

• These creatures live an average of 30-35 years in their natural environment. Those kept in captivity can live up to 50 years. Nippy, a Mueller's gibbon in New Zealand's Wellington Zoo, died at the age of 60, making him the world's longest-living primate.

Conservative Status of Gibbon Animals

• Because of the destruction or loss of their forest habitats, most gibbon species are endangered or severely endangered.

• These lesser apes are preyed upon by large cats native to Southeast Asia, such as clouded leopards and tigers. These arboreal apes are also threatened by large snakes and eagles.

• These animals are hunted in the wild to be sold to zoos. Some cultures buy animal parts for medicinal or culinary purposes.

• Human encroachment on the rain forests they call home, though, is by far the greatest threat to the gibbon animals. As civilisation occupies more and more of these forests, animals have less food and their habitats are fast dwindling, which is why so many species are threatened.

• The IUCN Species Survival Commission Primate Specialist Group declared 2015 the Year of the Gibbon and organised events in zoos throughout the world to raise awareness about the gibbons' situation.

Conclusion

Gibbons are apes that live in trees and can be found throughout Asia and Indonesia. Gibbons, also known as smaller apes as opposed to giant apes, are fast and agile, brachiating through the treetops at speeds of up to 35 mph. Siamang and lar gibbons are among the 18 species of an arboreal, or tree-dwelling, mammal. The majority of gibbon species are threatened, with several of them being highly endangered.