Adult Tonkin snub-nosed monkeys are known for their upturned noses and bluish facial skin. The species is recorded in limestone forests of northern Vietnam and eats leaves and unripe fruit.
Adults of both sexes have upturned noses. The back and outer limbs are black, while the chest and inner limbs have pale fur; bare skin around the nose and eyes is bluish. Coat color varies among individuals and populations.
Two small forest patches in Ha Giang Province, northeastern Vietnam, are the only places where Tonkin snub-nosed monkeys are now known: Khau Ca and Quan Ba. The forests are in one province but have different protection status. In Quan Ba, the last recorded sighting was on 22 June 2020.
In April 2024, a grid-based survey checked the monkey’s status in this forest using 2 km by 2 km cells. The team excluded cells heavily affected by farms or settlements and searched the others with biologists and community conservation members. Thirty-two surveyors walked 731 km in total while looking for evidence of the species.
An extinction-risk assessment has not been added yet.
The Tonkin snub-nosed monkey remains in two small forests in Ha Giang Province, Khau Ca and Quan Ba. Deforestation, cardamom farming inside forest, and intensive hunting have affected its habitat. In Quan Ba, it has not been sighted since 22 June 2020, and a survey on 17–21 April 2024 by 32 surveyors across 731 km recorded no significant signs. The survey used 2 × 2 km grid cells and excluded cells heavily affected by agriculture or human habitation. Community teams have worked in both forests for over a decade on forest protection and reducing illegal wildlife trade. The authors call for protected-area designation for Quan Ba, forest zoning, habitat restoration, monitoring and management plans, and an expansion programme for Khau Ca forest.