Recently, a research team from the Center for Technology and Nature Conservation (CTNC) has, for the first time, officially documented the presence of the Black-shanked Douc (Pygathrix nigripes) in the protected and special-use forest areas of Deo Ca, Tay Hoa, and Song Hinh. This region, formerly part of Phu Yen province, is now within Dak Lak province. This discovery, resulting from a rapid field survey conducted at the management boards of the Song Hinh, Tay Hoa, and Deo Ca special-use and protected forests in early August, provides crucial new information for primate conservation in Vietnam.

CTNC collaborated with the management boards of the special-use and protected forests in Song Hinh, Tay Hoa, and Deo Ca to conduct the field survey with the following objectives:

• Confirming the presence of endangered primate species, particularly those not previously recorded in the area.
• Assessing forest habitat quality and identifying potential threats.

The survey methodology included transect walks along ridges and up mountain peaks, supplemented by interviews with local residents to gather additional information. The survey teams navigated diverse terrains, tracking signs of the langurs such as feeding traces and scat.

The douc langurs are a group of primates endemic to Indochina, with Vietnam being home to all three species: the Red-shanked Douc Langur (Pygathrix nemaeus), the Gray-shanked Douc Langur (Pygathrix cinerea), and the Black-shanked Douc Langur (Pygathrix nigripes). The Black-shanked Douc, which is primarily distributed in the southern region, is the easiest to identify due to its distinctive solid black shanks, which contrast with the brown or silver-gray shanks of the other species. Its white face framed by black, broad forehead, long white beard, ash-gray body fur, and long white tail not only create a unique appearance but also make them perfectly adapted for arboreal life. As a highly rare species with a narrow distribution range facing severe threats, every new record of the Black-shanked Douc Langur holds special scientific and conservation value, helping to strengthen the database needed to protect one of Vietnam’s most precious biological treasures.

In the wild, the Black-shanked Douc (Pygathrix nigripes) is patchily distributed across the South Central Coast and Central Highlands, appearing in provinces such as Kon Tum, Gia Lai, Binh Dinh, Khanh Hoa, Ninh Thuan, and Binh Thuan. It thrives primarily in evergreen and mixed forests at low elevations. According to the latest survey at Nui Chua National Park (Ninh Thuan), from August 2022 to May 2023, 59 troops totaling 889 individuals were discovered, with the total population estimated at around 1,100 individuals. The populations recorded at Phuoc Binh National Park (Ninh Thuan) consist of at least 163 individuals, at Hon Heo Peninsula (Khanh Hoa) an estimated 109 individuals, and at Ta Kou Nature Reserve (Binh Thuan) approximately 64 individuals.

The species is currently classified as Critically Endangered (CR) on the IUCN Red List and Endangered (EN) in the Vietnam Red Data Book. Its population has declined by over 50% in the last 40 years due to habitat loss (logging and land-use conversion) and illegal hunting for meat, traditional medicine, or the wildlife trade.

The Deo Ca forest area, which stretches across Tay Hoa and Song Hinh, is one of the few remaining continuous forest tracts in the South Central Coast region. It plays a pivotal role in sustaining populations of rare wildlife. This area not only serves as an ecological corridor connecting several pristine forest systems but also provides a habitat for numerous endemic and Critically Endangered species, including the Black-shanked Douc. Documenting the presence of this primate species has significance far beyond a single discovery; it is an indicator that the region maintains an ecosystem large and intact enough to support species with demanding habitat requirements. This factor provides a scientific and practical foundation for considering conservation options at the highest level, ensuring the preservation of inter-regional biodiversity value and mitigating the risk of degradation from exploitation pressure.

“The discovery of the Black-shanked Douc Langur troop in the Deo Ca, Tay Hoa, and Song Hinh forest area is significant evidence and a highlight that could lead to the proposal of this region as a large national park. Currently, the combined area of the three management boards is nearly 70,000 hectares, and when combined with the continuous protected forest area in northern Khanh Hoa province, the total area could reach 130,000 hectares. If successful, establishing this region as a national park would make it the largest national park in Vietnam,”

Serious threats such as hunting, trapping, logging, and other impacts still exist in the area where the species was recorded. These findings show that important forest patches still remain for this critically endangered primate species (CR – IUCN), while also highlighting the need for additional surveys and the urgent implementation of conservation measures to protect the newly discovered population./