King of the swingers

Gibbons are breathtakingly acrobatic primates. As anyone fortunate enough to have woken to their haunting calls or witnessed the stunning spectacle of their high-speed swinging through the treetops will agree, an encounter with these charismatic canopy dwellers is a real highlight of a visit to the Southeast Asia forests that they call home.

They belong to the branch of primates known as lesser apes – partly due to the fact they don’t use tools and are considered less intelligent than chimpanzees and other great apes such as orang-utans.

Gibbons usually pair for life and live in very small family groups. They defend their territories mainly by singing. The dawn duets between male and female gibbons are one of the most evocative sounds of the forest. Many gibbon species – including the cao vit gibbon – are sexually dimorphic, meaning that males and females are different colours.

Although their preferred method of locomotion is swinging from branch to branch by their arms – known as brachiation – they can also walk or run along thicker branches, using their long arms to balance like a tightrope walker.

The cao vit gibbon, also known as the eastern black crested gibbon, was thought to be extinct until it was rediscovered by FFI Vietnamese scientists in 2002. It is one of the most endangered primates in the world, clinging to survival by its hooked fingertips in a small, fragmented forest on the border between Vietnam and China.

At a glance
Nomascus nasutus
Critically Endangered Critically Endangered
Vietnam Vietnam China China





Est. in the wild:



  • Like the cuckoo, the cao vit gibbon is named after its call.
  • Most gibbons are monogamous, remaining with the same mate for life.
  • Like all apes, gibbons lack a tail.
  • Gibbons are fond of fruit, especially figs, but also eat leaves, flowers, insects and even birds’ eggs.
  • Male and female cao vit gibbons can be distinguished by their fur colour, which is black and buffish-yellow respectively.
  • Gibbons have the longest arms of any primate, relative to body size.

The cao vit gibbon was believed to be extinct until its rediscovery in 2002.


The estimated number of cao vit gibbons surviving in the wild.

34 mph

The speed at which gibbons can swing through the treetops.


Unfortunately, remorseless hunting and widespread habitat loss have left many of the world’s 18 gibbon species precariously close to extinction, and the cao vit gibbon is no exception. Its entire global population is believed to be confined to a single location on the border between Vietnam and China.

Like other gibbons, it is a target for hunters, but the most serious threat to its survival is habitat loss and degradation as a result of firewood collection and livestock grazing.

Many of the forest landscapes where FFI works in Southeast Asia support important populations of gibbons. Vietnam is the global stronghold for the so-called crested gibbons, harbouring six of the world’s seven species.

One of the most urgent priorities of FFI’s Vietnam Programme is to highlight the country’s importance for gibbon conservation and to ensure the survival of the country’s four rarest species – including the cao vit gibbon.


Since rediscovering the cao vit gibbon, FFI has been working with local partners to set up community-based patrol groups, secure formal protection for crucial gibbon habitat and reduce threats in the buffer zones that surround this protected area.

We have encouraged and enabled communities to participate actively in the management of their local forest. In 2012, governments in both Vietnam and China signed an agreement to strengthen transboundary cooperation to conserve this threatened and charismatic primate.

Thanks to the combined efforts of FFI and our partners, hunting and habitat loss in this particular area have been virtually eliminated, with the result that cao vit gibbon numbers have stabilised and rebounded to an estimated 135 individuals, more than double the population at the time of its rediscovery in 2002.

A vital facet of our work is to ascertain whether the area of forest that currently harbours the cao vit gibbon can support a growing population. There are signs that gibbon numbers may now have peaked within the confines of their existing forest haven, and FFI is now working to secure additional habitat that could accommodate further expansion of the population.