Matt Walker BBC News 21 Sep 10
Gibbons have become the "forgotten apes" and many species will soon go extinct unless urgent action is taken.
So say primate experts who have made a call to action to save the crested gibbons of southeast Asia, which are the most vulnerable group of all apes.
For example, just 20 Hainan gibbons survive on one island in China, making it the world's rarest ape species.
Experts highlighted the status of the apes at the XXII Congress of the International Primatological Society.
"The crested gibbons are the most threatened group of primates and all species require urgent attention to save them from extinction", says Dr Thomas Geissmann, a world-renowned gibbon expert based at the University of Zurich in Switzerland, and advisor on the apes to conservation organisation Fauna and Flora International (FFI).
No less important
There are two main groups of apes.
Great apes include gorillas, orangutans, chimpanzees and bonobos.
Although also threatened, these species tend to receive more attention and conservation funding.
Gibbons make up the other group of apes, sometimes being described as "lesser" apes, though experts increasingly prefer to use the less pejorative "smaller" apes.
Gibbons pair-bond as humans do, but unlike great apes.
Of the different types of gibbon, there are seven species of crested gibbon.
All are highly threatened and some are among the world's most endangered mammals.
They are found east of the Mekong River in Cambodia, Lao PDR, Vietnam and China.
Several species have declined drastically over the past decade due to hunting and habitat loss caused mainly by rapid economic development.
Just two small groups of Hainan gibbons remain, living as two family groups on Hainan Island, China.
The Hainan gibbon's closest relative is the cao vit gibbon, which survives in a patch of forest on the border between Vietnam and China, and numbers not much more than 100 individuals.
Conservation work will be key to their survival, say the primate experts, meeting at the XXII Congress of the International Primatological Society held in Kyoto, Japan.
"Current efforts by FFI appear to be turning round the fortune of the cao vit gibbon at the eleventh hour," said Paul Insua-Cao, FFI China-Indochina Primate Programme Manager.
But gibbon conservation attracts much less funding than that of the great apes such as gorillas and orangutans, a situation that must be urgently remedied if this group of apes is to be saved, say the experts.
