A new survey of the cao vit gibbon has counted roughly 77 to 89 animals living in about 14 family groups, up from a confirmed 74, according to early findings reported by Discover Wildlife. The count, carried out in September by rangers, local community members and conservationists working with the charity Fauna & Flora, suggests a species once thought extinct is slowly growing.

The cao vit gibbon, Nomascus nasutus, is often described as the world's second-rarest ape. It survives only in a small patch of forest straddling the border between northern Vietnam and southern China, and it is listed as Critically Endangered on the IUCN Red List.

The numbers are small, but direction matters — a population this size can be erased by a single disease outbreak, fire, or poaching spree, so a few added animals is meaningful for its survival odds and a sign that years of protection are working.

A Count Built on Songs and Thermal Drones

Gibbons are hard to count by sight. They live high in steep limestone forest and move quickly through the canopy. The previous estimate of 74, announced by Fauna & Flora in January 2024, used a technique called vocal fingerprinting, which identifies individual males by their distinctive songs recorded at nearly 30 listening posts.

Drones carrying thermal cameras helped locate family groups. That survey also revised an older estimate of about 120 animals down by 38%, after researchers concluded earlier methods had double-counted some groups.

Project lead Oliver Wearn said at the time that the approach "is not only more accurate, but is non-invasive," according to Fauna & Flora. Sources differ on when that baseline survey was conducted: Discover Wildlife describes 74 as the 2021 figure, while Fauna & Flora's project page refers to a 2023 survey.

Signs of Slow Growth on the Vietnam-China Border

The new range of 77 to 89 is a preliminary estimate, and its upper and lower ends tell different stories. At the low end, the population has grown by three. At the high end, it has grown by 15. Fauna & Flora's project page also reports that baby gibbons were seen in both 2024 and 2025, which supports the idea of steady breeding.

The species was rediscovered in 2002 by Vietnamese scientists working with Fauna & Flora, after decades with no confirmed sightings. Since then, Vietnam created the Cao Vit Gibbon Species and Habitat Conservation Area in Cao Bang Province in 2006, and China established Bangliang Nature Reserve in Guangxi in 2007. The two countries signed a cross-border conservation agreement in 2012.

Community patrol teams set up in 2003 now monitor the forest, and Fauna & Flora's project page says there has been no hunting or major habitat destruction in the last 15 years. Partners include the Cao Bang Forest Protection Department and the People Resource and Conservation Foundation.

A Forest That Can Only Hold So Many

The hopeful trend runs into a hard limit — the gibbons live in a single forest block, and Wearn has said it could not support more than about 200 gibbons even in the best case. Without new habitat, growth will stall.

Inbreeding is another worry for so small a group. Paul Garber, an emeritus primatologist at the University of Illinois who was not involved in the survey, told Mongabay in 2024 that "The reality is nonhuman primates are really the canary in the coal mine." Mongabay listed habitat loss, farming expansion, mining, past charcoal production and capture for the pet trade among the long-term threats.

The preliminary numbers come with caveats. Survey methods and effort can change between counts, and early estimates may shift once data are fully analyzed. A wide range like 77 to 89 also reflects real uncertainty about how many gibbons were missed.

Corridors, Patrols and What Comes Next

Fauna & Flora's plans focus on giving the gibbons room to grow. Tree planting and assisted natural regeneration aim to reconnect forest patches, and the group hopes to expand protection to nearby forest and upgrade the area to a nature reserve. Longer-term ideas include establishing a second population through habitat corridors and translocation.

Rangers and nearby villagers carry much of the daily work. Fauna & Flora began habituating the first gibbon group in Vietnam in 2020, getting the animals used to people so they can be observed without stress, and the team also relies on acoustic recorders and thermal drone surveys. Those tools make future counts more consistent, which will help show whether the new estimate reflects real growth.

Local livelihoods are part of the strategy. Since 2022, cooperatives and social enterprises in agriculture and community tourism have aimed to give nearby villages income that does not depend on clearing forest. An international action plan covers 2021 to 2030, with a vision extending to 2050.

For readers far from Vietnam, the story offers a measured lesson in conservation. Recovery is possible even for a species on the edge, but it takes decades of patrols, cross-border cooperation and community support. Readers who want to help can support established conservation groups and avoid buying wildlife products or primate pets, which fuel the trade that threatens apes.

The final survey results are expected after analysis is complete. The bottom line is that the world's second-rarest ape appears to be inching upward, with as many as 89 animals counted, but it still lives in one small forest that will need to grow before the gibbons can.

What Readers Want to Know

How many cao vit gibbons are left?

Early results from a September 2026 survey estimate about 77 to 89 in roughly 14 family groups.

Is the population growing?

It appears so. The previous confirmed count was 74, and baby gibbons were seen in 2024 and 2025.

Where do cao vit gibbons live?

Only in a small forest on the border between northern Vietnam and southern China.

Why is it called the second-rarest ape?

Conservation groups describe it that way because so few individuals remain in the wild.

What are the main threats?

Hunting, habitat loss and degradation, and the risks that come with a tiny, isolated population, including inbreeding.

How are conservationists helping?

Through community patrols, protected areas in both countries, reforestation to create corridors and local livelihood programs.