The crested gibbon or the crested is one of the rarest and most endangered primates on Earth and survives only in a single piece of forest of less than 5,000 hectares, on the border between Vietnam and China. To this day, it was thought that there were still some left in the world about 120 individuals in all, but the new study unfortunately lowered this already dramatic estimate further. Using a new monitoring system that made it possible to identify thanks to technology voice signatures of individualsthe scientists calculated that they were fair 74 gibbons lefti.e. 38% of previous estimates.
These alarming data that push even closer to the brink of extinction this species, according to a study recently published in the journal Scientific reportsa work that took years and was led by local researchers and preservationists a non-governmental organization Flora and faunawho now hope to be able to instigate more effective and targeted conservation measures to save the last crested gibbons and their unique songs. This species, like other gibbons, produces unique vocalizationactual songs that scientists used to more accurately estimate the individuals found.
Nomascus nasutusthis is the scientific name of the species, it is also known as gibbon “cao-vit”, a term used by local populations in Vietnam to identify the species and inspired by their iconic vocalizations. Even scientists who study these very rare primates now prefer to call it this way: at least since 2002when the species was rediscovered in the country after being long thought to be extinct. In fact, there were no further sightings from the 1960s to the 21st century, but the joy of its rediscovery may now have been dampened by these latest and less encouraging estimates.
In this new study, the researchers used for the first time a technique called “vocal fingering”in which acoustic recorders are used to listen to gibbon songs and identify each individual’s voice signature. As far as we humans are concerned, each gibbon’s song is actually unique, just like the gibbon’s song men (with black fur), which is particularly characteristic. The researchers then installed almost 30 listening stations throughout the forest, recording songs at dawn until morning, when these primates are particularly talkative.
The census was also supplemented with more standard monitoring activities and usage drones equipped with thermal cameraswhich allowed the team to locate and count the number of individuals in the forest much more precisely. And the estimates speak for themselves: 74 cao-vit gibbons remain, all divided in 11 different family groups. The species is thus much closer to extinction than previously thought, an alarming fact, but one that will serve as a firmer basis for better direct management and conservation actions and monitoring their success over time.
In reality, all is not lost, also because despite this new downward estimate there is no evidence that the population has declined in recent years indeed. According to experts, the number of gibbons However, it is growing and long-term follow-up has emerged in recent years new family groups. By studying the voice signature, the researchers were then able to paint a much clearer picture of the population size and location of each group’s territory.
This new method is not only more accurate, but also less invasive, which allows the gibbons to study without disturbing them when in their natural habitat. However, the gibon cao vit is clearly endangered much more immediate than previously thought due to the threats associated with very small size from the population. However, conservation measures have been in place to protect this elusive primate since it was rediscovered in Vietnam in 2002 and then in China in 2006.
They are among them establishment of two protected areasregular patrolling by rangers and local groups to prevent poaching, long-term monitoring and research of the species, habitat restoration and sustainable management of natural resourcescooperation between the two countries on the protection of the species and, above all, awareness about the plight of gibbons through educational events in schools and with local communities. In fact, it is only through dedication and involvement who live in these territories that the cao vit gibbon and its unique song can be assured of a future.