The Song of the Gibbons is a Dying Tune

The melodic call of the gibbon, a small tree-dwelling ape, can be heard echoing far off in the jungle. Scientists often determine a gibbon community’s size by counting and listening to their distinct voices. Recently, however, researchers have noticed a growing silence in tropical forests -- a sure sign that gibbon populations are on the decline.

Last week at the 23rd Congress of the International Primatological Society, gibbon experts and conservationists elaborated on the gravity of the situation, especially the plight of the crested gibbon species, in a series of lectures. Deforestation, from expanding agriculture, logging, and climate change, combined with illegal hunting are pushing these primates towards extinction.

“The crested gibbons are the most threatened group of primates and all species require urgent attention to save them from extinction,” Thomas Geissman, a gibbon expert from Zurich University and advisor of the conservation organization Fauna and Flora International said in a conference press release.

Gibbons are often referred to as the “lesser” apes because they are significantly smaller than their great ape relatives, such as orangutans, chimpanzees, gorillas, and bonobos. Gibbons are easily identifiable by their flat faces, their long arm-to-body ratio, and their lack of tails. These small apes are slender, agile primates that spend most of their time swinging through the trees, but are known to walk upright across the forest floor, arms held up to assist with balance.  

The slender primates are distributed across Asia, with crested species found east of the Mekong River in Laos, Cambodia, Vietnam, and southern China. German scientists today even announced the discovery of a new type of crested gibbon -- the northern buffed-cheeked gibbon -- in the tropical rainforests of Vietnam, Laos and Cambodia.

The Hoolock gibbons are the most endangered gibbon species with about 20 individuals left, residing in two family groups on China’s Hainan Island. Hoolock’s closest relative is also critically endangered, with around 100 individuals left scattered around patches of forest along the Vietnam-China border.

According to an article on Mongabay, "Of the seven species of crested gibbon, three are listed by the IUCN Red List as critically endangered, four are endangered, and one is vulnerable to extinction." In terms of population size, there are less than 10,000 total crested gibbons left.  

Gibbons live in tree canopies and feed on fruits. Their lifestyle is not easily adaptable to different landscapes, making them very vulnerable to decline from deforestation. Logging and expanding human developments are eating up precious gibbon habitats across Asia. Additionally, the increase in wild fires and changes in biodiversity due to climate change are exacerbating the situation. 

Protecting crested gibbons requires more surveying of primate populations, an increase in monitoring of known strong-hold locations, and working to improve habitats and decrease deforestation pressures. Sound familiar? These are the same issues plaguing declining animal populations around the world, from tigers to frogs.

Earth's biodiversity is in poor shape and it is time we start taking responsibility. To find out what you can do to help the gibbon cause, check out the conservation initiatives led by Fauna and Flora International. 

Image: Bill Bleisch, FFI