The cao vit gibbon, the world’s second rarest ape, can be found only in a small patch of forest on the border between Vietnam and China. In 2021, its population size was confirmed to be just 74 – but the latest survey, conducted in September 2026, suggests it has grown.
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The survey, completed by local community members, rangers and conservationists from international conservation charity Fauna & Flora, is the first one since 2021. Early findings indicate that the total population within an estimated 14 groups is approximately 77–89 individuals.
The cao vit gibbon (Nomascus nasutus) is listed as Critically Endangered on the IUCN Red List, threatened by hunting, habitat loss and degradation. It was thought to be extinct until it was rediscovered in 2002 by Vietnamese scientists from Fauna & Flora. Since then, the organisation has been working with local partners to set up community-based patrol groups, secure formal protection and reduce threats to the gibbons’ habitat.
The cao vit gibbon, like most gibbon species, is sexually dimorphic, meaning that females and males are different colours – pale, brownish yellow and black, respectively.
Cao vit gibbons caught on camera
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Top image: Two cao vit gibbons in tree canopy. Credit: Nguyen Duc Tho / Fauna & Flora
