Singing in the rain forest: Gibbons have accents

One of 2,500 yellow-cheeked crested gibbons counted in a 2008 Wildlife Conservation Society survey in Cambodia.

Groups of the apes have their own ways of singing, which vary by location

2/7/2011
By Jennifer Welsh
LiveScience

Gibbons have regional accents, a new study suggests. While not a sexy Southern drawl, these accents can help scientists identify the species of gibbon singing and where they are from.

"Each gibbon has its own variable song but, much like people, there is a regional similarity between gibbons within the same location," lead researcher Van Ngoc Thinh, from the Primate Genetics Laboratory at the German Primate Center, said in a statement.

The crested gibbons in the genus Nomascus, which live in the Asian rain forests of China, Laos, Cambodia and Vietnam, use their songs to communicate with other gibbons. They also use singing to bond with mates and define territory. The songs are specifically adapted to travel over long distances through the dense vegetation of the rain forest by concentrating all of the energy into a single frequency, similar to the calls used by rain forest birds.

New ape species uncovered in Asia

This photo from the Wildlife Conservation Society (WCS) shows a Yellow-Cheeked Crested Gibbon. Crested gibbons are found only in Vietnam, Laos, Cambodia and southern China. Scientists at the Germany Primate Centre say they have discovered a new species of the ape by identifying its distinctive song. (AFP/Ho)

September 21, 2010
Jeremy Hance
mongabay.com

Discovering a species unknown to science is a highlight of any biologist's career, but imagine discovering a new ape? Researchers with the German Primate Center (DPZ) announced today the discovery of a new species of ape in the gibbon family, dubbed the northern buffed-cheeked gibbon (Nomascus annamensis), according to the AFP. The new species was discovered in rainforests between the borders of Vietnam, Laos, and Cambodia: an area that contains a number of gibbon species.

The new species had been thought by past researchers to be the yellow-cheeked gibbons (Nomascus gabriellae), however analysis of the animals’ DNA and distinct calls convinced researchers that although the species looks almost exactly like yellow-cheeked gibbons, they were in fact a wholly different gibbon.

Both of the gibbons belong to the family of 'crested gibbons', one of the most imperiled groups of mammals in the world. Yellow-cheeked gibbons are currently classified as Endangered by the IUCN Red List due to habitat loss, hunting, and the pet trade. Other crested gibbon species are down to less than 200 individuals.

"The crested gibbons are the most threatened group of primates and all species require urgent attention to save them from extinction", Thomas Geissmann, gibbon expert from Zurich University and adviser with Fauna & Flora International (FFI), recently said.

It's likely this new species—the northern buffed-cheeked gibbon—is also facing extinction, yet more research needs to be conducted. Many of the crested gibbons have been under-researched to date and scientists are still uncertain of some species' range and population making conservation efforts difficult. Gibbons have long been overlooked by researchers and conservationists compared to their more popular ape relatives.

Scientists have dubbed gibbons the 'lesser apes' since they share some behavioral and physical characteristics with monkeys, but, like all apes—gorillas, chimpanzees, orangutans, and humans—they possess no tail. Gibbons are known for their high-flying rapid-swinging antics among their lives in trees and their booming unmistakable songs. They are the world's fastest arboreal mammal without the power of flight.

Scientists warn little known gibbons face immediate extinction

A cao vit gibbon, a subspecies of the eastern black crested gibbon, in the new Bangliang Cao Vit Gibbon Nature Reserve. Photo by: Zhao Chao, FFI.
Hainan gibbon with infant. Photo by: Bill Bleisch, FFI.

September 19, 2010
Jeremy Hance
mongabay.com

It's not easy to be a gibbon: although one of the most acrobatic, fast, and marvelously loud of the world's primates, the gibbon remains largely unknown to the global public and far less studied than the world's more 'popular' apes. This lack of public awareness, scientific knowledge, and, thereby, conservation funding combined with threats from habitat loss to hunting to the pet trade have pushed seven gibbon species, known as 'crested', to the edge of extinction according to scientists attending the 23rd 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", Thomas Geissmann, gibbon expert from Zurich University and advisor with Flora and Fauna International (FFI), said in a statement

Gibbons, who spend their lives in trees, have been dubbed the 'lesser apes', for while gibbons do not have a tail like other ape species—gorillas, chimps, and orangutans—they share some other characteristics with monkeys. The seven gibbon species of concern inhabit regions east of the Mekong, including Laos, Cambodia, Vietnam, and China.

The situation is bleakest for the eastern black crested gibbon. This species is not only the world's most endangered gibbon, but likely the most endangered primate. Split into two subspecies—the cao vit and the Hainan—the eastern black crested gibbon has in total just over 100 individuals surviving. Only 20 or so Hainan gibbons survive in China, while the cao vit gibbon is faring just a little better.

"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 program manager, in a statement. "FFI has been championing conservation of several of the world’s rarest gibbon species for more than a decade. The organization is working with local communities and government authorities across the range states of these gibbons to protect them and their habitat".

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. One would be hard pressed to find another mammalian group so imperiled. In fact, two of the species—the eastern black crested gibbon and the western hoolock gibbon—appear on the world's top 25 most endangered primates list.

New surveys in largely unexplored regions have found unknown populations of some gibbon species, yet the situation remains dire for many. Gibbon experts say more action is needed if these apes are to saved from extinction.

Yellow-cheeked crested gibbon at Ta Mao Zoo

I vant to dreenk your blahhd: When visiting Cambodia's Phnom Tamau Zoo, be sure to take along some garlic and a sharpened wooden stake. (Yellow-cheeked crested gibbon.) (Heng Sinith / AP)

Unexpected Large Monkey Population Discovered

ScienceDaily (Aug. 28, 2008) — A WCS report reveals surprisingly large populations of two globally threatened primates in a protected area in Cambodia.

The report counted 42,000 black-shanked douc langurs along with 2,500 yellow-cheeked crested gibbons in Cambodia's Seima Biodiversity Conservation Area, an estimate that represents the largest known populations for both species in the world.

WCS scientists conducted the surveys with the Royal Government of Cambodia's Ministry of Agriculture, Forestry and Fisheries across an area of 300 square miles (789 square kilometers) within a wider landscape of 1,150 square miles (3,000 square kilometers), which is about the size of Yosemite National Park. The scientists believe total populations within the wider landscape may be considerably greater.

The WCS scientists who worked on the census include Tom Clements, Nut Meng Hor, Men Soriyun, Edward Pollard, Hannah O'Kelly, and Samantha Strindberg.

The data were first presented at the International Primatological Society Congress held recently in Edinburgh, Scotland. WCS also announced at the IPS Congress the discovery of 125,000 western lowland gorillas in northern Republic of Congo, where conservation work has been ongoing since the early 1990s.

"Whether it's protecting gorillas in the Republic of Congo or monkeys and gibbons in Cambodia, conservation can and does work when you have government commitment and scientific knowledge on the ground ," said Dr. John G. Robinson, Executive Vice President for Conservation and Science for the Wildlife Conservation Society. "Now we must put into place the management to truly protect these populations and apply the approach to other regions where primates are in trouble."

The two primate species are found in much lower numbers at other sites in Cambodia and in Vietnam. Prior to the recent discovery in the Seima Biodiversity Conservation Area, the largest known populations were believed to be in adjacent Vietnam, where black-shanked douc langurs and yellow-cheeked crested gibbons hover at 600 and 200 respectively. The total population of the two species remains unknown.

The recent census in Cambodia took place in a former logging area where the two monkeys were once extensively hunted. Then in 2002, the Minister of Agriculture, Forestry and Fisheries declared the region a conservation area and began working with WCS on site management and landscape-level planning for conservation and local development.

According to WCS, a combination of factors account for such high numbers of primates: successful long-term management of the conservation area; cessation of logging activities; a nation-wide gun confiscation program implemented in the 1990s; and habitat where there is plenty of food. The report says that the two primate populations started to recover in 2002 when the joint program between WCS and the Royal Government began and have remained stable since 2005.

The news on primates is not all good. In Cambodia, WCS researchers are concerned that looming threats could jeopardize recent successes.

"Despite this good news in Cambodia, the area still remains at risk from conversion to agro-industrial plantations for crops, including biofuels, and commercial mining," said Tom Clements, the lead author of the WCS report. "WCS is therefore committed to continuing to work with the Cambodian Government to ensure that these globally important primate populations will continue to remain secure."

WCS has worked with the Royal Government of Cambodia since 1999, helping to establish the Seima Biodiversity Conservation Area, and developing landscape-level conservation programs in the Northern Plains and Tonle Sap Great Lake.

WCS work in Cambodia has been supported by U.S. Fish and Wildlife Service's Great Apes Conservation Fund, MacArthur Foundation, Liz Claiborne Art Ortenberg Foundation, ADB Greater Mekong Subregion Core Environment Program, and the Danish Government's Danida program.
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Adapted from materials provided by Wildlife Conservation Society, via EurekAlert!, a service of AAAS.