A large population of 455 individuals of the rare Northern white-cheeked gibbons have been discovered in the forests of Vietnam, near the border with Laos. This community amounts to about two-thirds of the members of the species existing in Vietnam.
Experts from Conservation International (CI) announced yesterday the discovery of a population of 455 Northern white-cheeked gibbons (Nomascus leucogenys), a species of smaller-apes classified as in critical danger of extinction. The announcement is the result of almost three years of field work led by Vietnamese primatologist Dr. Luu Tuong Bach and CI researcher Benjamin M. Rawson .
The community is divided into 130 family groups. The primates were found in remote high-altitude forests in Vietnam’s Pu Mat National Park. Pu Mat is located within the Annamese Mountain Range which extends for over 1000 kilometres through Laos, Vietnam, and part of northeast Cambodia.
Northern white-cheeked crested gibbon (Nomascus leucogenys), Vietnam. Adult female with baby and adult male (Conservation International).
This community becomes the largest known population of the species and the only one considered to be viable because of its size. The number of individuals in the population was estimated by analyzing audio recordings of their vocalizations. These primates, classified as smaller-apes (to differentiate them from the large apes, i.e. gorillas, orangutans and humans) are territorial and monogamous. They communicate through an elaborate and specific set of vocalizations known as “singing”. They sing to establish control of their territory and during mating rituals. They show a matriarchal family arrangement where the female is the leader of the family, followed in the hierarchy by female offspring, male offspring, and lastly, the adult male.
Female Northern White-cheeked Gibbon (Nomascus leucogenys). The common name comes from the prominent white colouring on the cheeks of the male of the species. Captive in the Adelaide Zoo, Australia.
Although these gibbons are not sexually dimorphic in size, males and females differ in fur colour. All white-crested gibbons are born with light cream-coloured fur. The adult females retain their light coloration, but the adult males turn black and develop white furry patches on their cheeks.
“I have worked with gibbons for the past 10 years, and the more I learn about them, the more I admire them and the more concerned I become about their future. All 25 of the world’s gibbon species and sub-species are threatened with extinction, with wild populations suffering from hunting and habitat loss and degradation. Given this depressing outlook, our recent discovery in Vietnam of the only known viable northern white-cheeked crested gibbon population left in the world is a beacon of hope for this amazing primate.” says Dr. Ben Rawson in the CI website.
"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," said in a statement Russell A. Mittermeier, president of Conservation International.
At the XXIII Congress of the International Primatological Society held in Kyoto in September 2010, the world’s gibbon experts, led by Fauna & Flora International (FFI), made a call to action to save the crested gibbons of South East Asia. All 7 species of gibbons living in Vietnam, Laos and Cambodia are considered critically endangered with the Eastern black-crested gibbon (Nomascus nasutus) from Southern China deemed the rarest and most critically endangered primate in the world. The remaining population of this species living in the wild is estimated in about 110 individuals.
Listen to a Northern white-cheeked gibbons singing duet here.
Landscape in Pu Mat National Park, Annamite Mountain Range in NorthEast Vietnam.