Identification:
Slender body, with dark gray fur on the crown of the head. The body color ranges from gray to black, with light gray or yellow hair tips, creating a silvery appearance. The face is pale, and the abdomen is light gray. Long limbs and a long tail; the underside of the tail has a slightly yellowish hue. Newborns are orange, transitioning to gray at 3-4 months of age.
Biology and Ecology:
The primary diet consists of leaves (80%), tree shoots (10%), and fruits (10%). Approximately 100 plant species are used as food sources. There have been no observed instances of animal consumption. This species is diurnal and arboreal. The social structure is led by a single dominant male. Infants have a very distinct orange color for the first six weeks. Males show less interest in the young. The typical social structure consists of one male and multiple females. Group sizes range from 15 to 38 individuals. The primary habitats are evergreen forests, primary forests, secondary forests, coastal mangroves, and forest edges along rivers. They prefer to inhabit low-lying mountainous areas below 500m, but have also been observed at altitudes above 1,000m (1,737m). They typically live and forage at heights of 10-50m.
Distribution:
- In Vietnam: Gia Lai (A Zun Ba), Kon Tum (Đắk Lây, Đắk Tô, Mom Ray, Sa Thầy), Đắk Lắk (Đắk Nông, Buôn Ma Thuột, Ea Súp, Buôn Đôn), Phu Yen, Nha Trang, Lam Dong, Dong Nai (Cat Tien), Kien Giang.
- Worldwide: Southern and Southeast Asia.
Value:
High scientific value; it is a subject of scientific research and is used in experiments for vaccine research to benefit human life.
Conservation Status:
Before 1975, this species was commonly found in the old-growth forests of the southern provinces and the Central Highlands of Vietnam, with an estimated area of >2,000km². Since 1975, the species’ status has changed dramatically. The population has significantly decreased. There are currently >10 subpopulations. Possible causes for the decline include habitat loss, deforestation, the reduction of natural forest area, and hunting for traditional medicine (e.g., making medicinal paste), trade, and export.
IUCN Red List Category:
VU A1c,d (Vulnerable)
Conservation Measures:
Included in the Vietnam Red Book 2000 and the list of protected species of the forestry sector (Appendix IB, Decree 32/2006/ND-CP, April 22, 2002). Effective enforcement of laws, regulations, and Government Decrees in the conservation of wild animals is necessary. The establishment of nature reserves and the development of management programs for wild animals in general, and threatened species in particular, are essential. This species is currently protected in reserves such as: Yok Don National Park (Đắk Lắk), Cat Tien (Dong Nai, Lam Dong), Chu Mom Ray Nature Reserve (Kon Tum), Phu Quoc National Park (Kien Giang).