Largest Population of Critically Endangered Gibbon Discovered in Vietnam


Conservation International scientists urge high priority protection for “global stronghold” of threatened primates; only known viable population left worldwide


Pu Mat National Park, Vietnam — Conservation International (CI) has discovered the largest known remaining population of the critically endangered northern white-cheeked crested gibbon (Nomascus leucogenys) in Vietnam. Through auditory surveying, a technique which uses the species loud morning calls for identification, CI has confirmed a substantial population of 130 groups (455 animals), making this the highest priority for conservation action for the species globally. (Photos are available for download)

This newly censused population represents over two-thirds of the total population of the northern white-cheeked crested gibbon in Vietnam and is the only confirmed viable population of this species left worldwide. Historically distributed in China, Vietnam and Laos, this highly threatened primate is believed to be functionally extinct in China and the species situation is largely unknown in Laos, due to a lack of research, although significant numbers may still persist.

Dr. Russell A. Mittermeier, Chair of the IUCN/SSC Primate Specialist Group and President of Conservation International, said: “All of the world’s 25 different gibbons are threatened, and none more so than the Indochinese crested gibbons, eight of which, including the northern white-cheeked gibbon, are now on the brink of extinction. This is an extraordinarily significant find, and underscores the immense importance of protected areas in providing the last refuges for the region’s decimated wildlife”.

Work carried out by CI over the past three years within the species fragmented distribution in north-central Vietnam had until now returned sobering results, with no population larger than a dozen groups found. In 2010, the area of focus was changed to Pu Mat National Park, where CI and the park staff, with support from and Fauna & Flora International, Arcus Foundation and Sprague-Nowak SE Asia Biodiversity Initiative, used auditory sampling techniques to research this area.

Gibbons are territorial and communicate their boundaries with loud, elaborate and prolonged vocalizations. By recording these songs, data was gathered on the gibbon groups in the surveyed area and used to determine group numbers across the park. This relict population was discovered in remote, dense forest, at high altitudes on the Vietnam-Laos border, where they have been isolated from human populations. This latest discovery gives great hope for the future of this beautiful and unique primate.

However, road development in this area pose a serious threat to the gibbon’s future, as this global stronghold has persisted because of the remoteness of the habitat. These roads, designed to increase border patrols between Vietnam and Laos, will cut directly through the gibbon’s habitat. This could have catastrophic effects on this population, as the roads will fragment the habitat and provide access for illegal and harmful activities such as hunting and logging. Without protection this will inevitably lead to a decline in this last option for this species to exist in the wild in Vietnam.

Ben Rawson, regional primate expert for Conservation International, who has led the gibbon research project, explained: "We are extremely excited about this discovery. Pu Mat was already important for its great diversity of species and for its benefits to the surrounding communities, and now it is a top priority for global gibbon conservation.”

Rawson continued, “The fact that we are excited about the discovery of only 130 groups of northern white-cheeked crested gibbons is indicative of the state of this species and crested gibbons generally; they are some of the most endangered species in the world. It’s important to remember though that conservation in Pu Mat National Park is vital not just for biodiversity, but for its benefits to people also as this is a watershed which provides water for 50,000 people vital for drinking and agriculture.”

Primatologist Luu Tuong Bach, a consultant to CI, who led field surveys, added: “‘We don’t think we can stop the roads, so the best solution is targeted gibbon protection in key areas for this population. The major issue will be the hunting of these gibbons that were previously protected by the harsh terrain; so gun control will be vital. Without direct protection in Pu Mat National Park, it is likely that Vietnam will lose this species in the near future.”

Species facts:

White-cheeked gibbons eat mostly fruit, leaves, buds and flowers, occasionally feeding on eggs, young birds and insects. These lesser apes move and feed primarily in the tropical forest canopy, rarely descending to the ground.

Gibbons, called the smaller apes, differ from the great apes, as they smaller, have low sexual dimorphism and do not make nests. They are among the 6% of primates that form monogamous pairs which mate for life. They are the most romantic primate, singing to attract a partner, and to maintain their pair bonds they also sing to each other.

Vietnam holds six species of gibbons of the crested gibbon genus Nomascus. They comprise some of the most highly threatened primates in the world. There may be as few as 200 groups of northern white-cheeked crested gibbon left in Vietnam. An ongoing status assessment of Vietnam’s gibbons conducted by Conservation International and Fauna & Flora international shows that there have been precipitous declines in gibbon numbers across the country in the last 25 years. This has mainly been driven by land-use change, namely conversion of habitat, and hunting pressure for local consumption, the pet trade and assumed medicinal value of primate body parts.

Gibbons are highly arboreal and move by brachiation, and with their long arms and short legs, swinging from handhold to handhold under branches and vines, using their long fingers as hooks.


Available content for media:

Photos (*Mandatory image credits as stated in photo caption and metadata*): 

Gibbon call available for download (right-click and select "save"):
Whooping call of the northern white-cheeked crested gibbon

For more information, contact:

Ben Rawson Ph.D.
Veun Sai-Siem Pang Conservation Area Manager, Greater Mekong Program
Coordinator of the Primate Specialist Group, Indochina
+64 (0) 272495079 (New Zealand)
*Mr Rawson will be available for comment Monday and Tuesday (New Zealand time).

Emmeline Johansen
Communications Coordinator
+855 92968872 (Cambodia)

Patricia Yakabe Malentaqui
International Media Manager
+1 571 2258345 (U.S.)  

Note to editors:

Conservation International (CI) — Building upon a strong foundation of science, partnership and field demonstration, CI empowers societies to responsibly and sustainably care for nature, our global biodiversity, for the long term well-being of people. Founded in 1987, CI has headquarters in the Washington, DC area, and nearly 900 employees working in more than 30 countries on four continents, plus 1,000+ partners around the world. For more information, visit  and follow us on Twitter: @ConservationOrg or Facebook:   

Fauna & Flora International (FFI) is the world’s first established international conservation body, founded in 1903. FFI acts to conserve threatened species and ecosystems worldwide, choosing solutions that are sustainable, are based on sound science and take account of human needs. FFI operates in more than 40 countries world-wide.