Identification:
Distinguishing features compared to Golden Monkeys: Larger body size, thicker and longer fur. The tail is longer than that of Golden Monkeys. The posterior of the rump has fur (lacking in Golden Monkeys). Fur color can vary from dark brown to light yellowish-brown, but the shoulders, nape, crown, and ears are often lighter and yellower than the posterior legs and tail. The fur around the face is black, with gray fur on the cheeks, and grayish-white fur on the inner and lower thighs. The tail fur is lighter in color on the underside. The direction of the fur on the crown is very distinctive, growing outwards, branching right and left, and swirling at the base of the ears. The crest points backwards. They have cheek pouches and large ischial callosities, surrounded by fur. The tail is often thickest at the base, short (less than half the body length), but longer than 10% of the body length, and longer than the hind feet; the tail is not tapered, and is usually straight.
Biology and Ecology:
The species breeds year-round. Each birth produces one offspring. Infants are commonly observed in April, May, July, August, and October. Newborns weigh 300-500g. Their primary diet consists of fruit, young leaves, insects, lizards, and some small animals. They are diurnal, active during the day. They spend their lives climbing and also spend time on the ground. They often sleep in trees and on rock faces. Social structure: Multi-male, multi-female. The number of individuals in a group is usually large, from 10-50 individuals (Wolfheim, 1983). They live in tall forests on rock mountains and soil mountains, primarily inhabiting evergreen forests, sparse forests, bamboo forests, and fields near forests. They take shelter in caves under rock outcrops, or hide in dense thickets. They live in groups led by a dominant male who guards while the group forages. They may coexist with slow lorises, gibbons, red-faced monkeys, Golden Monkeys, Black Langurs, snub-nosed monkeys, or Indochinese gray langurs (Fooden, 1982). They are distributed at altitudes from 150-1200m, sometimes up to 1750m.
Distribution:
- Within Vietnam: From Lao Cai to Quang Binh provinces.
- Worldwide: Southern and Southeast Asia, ranging to Bhutan and China.
Value:
They are objects of scientific research. Additionally, with proper protection, they can serve as a source of animals for research and vaccine testing to benefit human life.
Status:
Prior to 1975, this species was commonly found in forests across the Northwestern provinces, in an area estimated to be >5,000 km². Since 1975, the status of the species has changed significantly. The population has declined sharply. There are currently approximately >15 subpopulations. The reasons for these changes are habitat degradation, deforestation, shrinking natural forest areas, and being hunted for meat, medicinal use, trade, and export.
Classification:
VU A1c,d. (Vulnerable)
Conservation Measures:
Included in the Vietnam Red Book 2000 and the list of species requiring protection by the Forestry Department (Appendix IIB, Decree 32/2006/ND-CP dated April 22, 2002, of the Government). Recommendations: Effective enforcement of laws, regulations, and decrees of the government regarding the protection of wildlife. Establishing natural reserves and management programs for wildlife in general and threatened species in particular.