Gibbon

Gray gibbon (Hylobates muelleri) at Paignton Zoo. Photo: Ray Wiltshire

Where do gibbons come from? Tropical and subtropical rainforests from northeast India to Indonesia and north to southern China, including the islands of Sumatra, Borneo and Java.
How big are gibbons? 5-8kg, Siamangs: 12-15kg
How do gibbons live? They live in pairs with their offspring.
Are gibbons threatened? All gibbon species are listed on the IUCN Red List ranging from Vulnerable to Critically Endangered.

There are seventeen* different species of gibbon. They are divided amongst four different genera: Hylobates, Nomascus, Hoolock and Symphalangus. Gibbons from the Hylobatus genus are spread out amongst southern China (Yunnan) to western and central Java, whereas gibbons from the Nomascus genus can be found in southern China (Yunnan), southern Vietnam, and also on Hainan Island. The Hoolock gibbons’ habitat ranges from  Assam in North-East India, to Myanmar. Small populations (in each case few hundred animals) live also in eastern Bangladesh and in southwest China. The Siamang (Symphylangus syndactylus) is the only species in the Symphalangus genus and they are native to the forests of Malaysia, Thailand, and Sumatra. Half of the sixteen gibbon species can be found in European zoos.

(*A newly discovered species, N. annamensis, was announced during 2010.)

Gibbons have an arboreal livestyle, which means they live in trees. Brachiation describes the gibbons’ typical way of moving through the treetops. They swing through the trees by grabbing hold of branches, using one hand then the other. They use their hands like hooks, not grasping the tree limb. At top speed, gibbons can easily move more quickly through the rainforest canopy than humans can walk. Due to their suspensoric (= ‘hanging’) lifestyle gibbons have become specialised foragers. They try to avoid competition for food with other animals by feeding on fruit and leaves on the thin outer branches of the trees, which other animals have difficulty accessing.

Gibbons live in pairs with their offspring. They “mark” their territory with bouts of loud songs (vocalisations), which usually last for a duration of 10 to 20 minutes (depending on the species). Other functions have been associated with the gibbons’ songs, such as mate attraction, mate defence and/or strengthening the bond between male and female. In most gibbon species, males and females may combine their songs to produce elaborate duet songs. Gibbon species can easily be recognised by their songs, because species-specific song characteristics are inherited.

Cao vit gibbon, China. There are fewer than 100 left. Photo: Zhao Chao/FFI

In ancient times, gibbons had a large range in China, and played an important role in Chinese culture. There are myths dating from about 150 years before Christ, that gibbons can transform into humans and that they can live for hundreds of years.

Unfortunately humans are playing a role in the demise of this charismatic species. The top three threats gibbons face are:

1. Illegal pet trade
2. Destruction of habitat
3. Inbreeding

Young gibbons are in demand for pets. The bond between parents and their young is very strong and an adult female gibbon will not willingly leave her infant when threatened. Therefore for a human to get the infant, it is most likely that the female will be shot and killed. The adult male could also be killed trying to protect his offspring and mate. As gibbons have a slow breeding rate the above issues are causing huge problems.

Forest fragmentation is also having a profound effect on the gibbon population as it prevents animals from migrating. This means they cannot go to new areas to form new unrelated pairs. As a result of this there is the potential for inbreeding, which is detrimental to individual the gibbons overall future and health.

More to read:

• www.gibbons.de

Word versions of these fact sheets are available to campaign participants under Resources -> Education. Links to additional sources of information can also be found under Resources.