Distinguishing Characteristics:
The primate has thick, coarse, black fur. The head has a black, cone-shaped crest. Wide, white patches of fur extend above the ears on the cheeks. The fur on the buttocks and thighs is white. In females, the fur color on the hips and thighs changes, normally white, turning light brown, and then dark brown during pregnancy and when nursing young. The tail is long, thick, fluffy, with hairs growing perpendicular to the tail, and black in color. The face is hairless. The eyes are dark brown. Newborn primates have golden-yellow fur that gradually turns black after four months. After ten months, the entire body turns clearly black, with white hips and thighs, and a light yellow crest on the top of the head. After three years, the fur color is similar to that of adults.
Biology and Ecology:
White-rumped primates primarily live in forested areas on limestone mountains. However, due to habitat fragmentation, they also inhabit degraded forest environments, including those with only vines and dense shrubs (Vân Long, Ninh Bình). Like other species, white-rumped primates live in social groups. Field surveys show that the number of individuals in a group varies from 5 to 10. The foraging range of white-rumped primates is relatively broad, encompassing both mountainous and rocky areas, but they sleep on rocky mountains. During the hot season, white-rumped primates sleep on cliffs, and during the cold season, they sleep in caves. They forage twice a day, in the morning and afternoon, with a rest period at midday. Studies in captivity show that primates usually take a nap starting around 12:00, waking up around 13:00. The nap duration ranges from 37 to 60 minutes. White-rumped primates eat leaves, young shoots, and fruits from forest trees.
They do not consume animal products. Research on food at the Cúc Phương Primate Rescue Center has recorded white-rumped primates eating 204 plant species from 57 families. Among the 204 plant species consumed, white-rumped primates eat shoots and leaves of 203 species, flowers of 16 species, fruits of 13 species, tubers of 3 species, and bark of 10 species. The average daily food requirement is 1184g (equivalent to 16.91% of body weight) and depends on sex, age, and weather conditions (mainly temperature) during the day. Daily water intake varies from 400 to 500 ml per individual.
Their natural predators are large carnivores.
Reproductive data on white-rumped primates is limited. Observations at the Cúc Phương Primate Rescue Center show that mating behavior in white-rumped primates usually occurs at two times: early in the morning and after the afternoon meal. Mating lasts 15 to 30 seconds. The average gestation period is 196 days. The breeding season is concentrated from December to August. Each litter produces one offspring, which weighs 350-500g at birth. Newborns have yellow fur. Primates reach sexual maturity at 5 years old.
Distribution:
- Within Vietnam: Yên Bái (Văn Chấn), Hòa Bình (Chi Nê), Ninh Bình (Cúc Phương, Vân Long), Thanh Hóa (Hồi Xuân, Lang Chánh), Nghệ An (Quỳ Châu, Con Cuông), Hà Tĩnh (Hương Sơn).
- Worldwide: Only in Vietnam.
Value:
The white-rumped primate is a unique and precious gene resource. Studying their ecological behavior helps in understanding human evolution.
Status:
White-rumped primates were once relatively widespread. Due to habitat loss, their distribution has shrunk, and due to hunting, the population has severely declined. It is estimated that there are currently about 270-302 individuals remaining (Nadler T., 2001).
Classification:
CR A1c,d C1+2a
Conservation Measures:
Listed as Endangered (E) in the Vietnam Red Data Book (1992). Classified as Critically Endangered (CR) by the Primate Conference in October 1998 in Hanoi, and the IUCN (2000). Listed in Appendix II of CITES. Protected under Decision 194-CT (1986) on regulations for protected forests; Law on Forest Protection and Development (1991), group IB in Decree 32/2006/ND-CP. Protected in Cúc Phương National Park, Vân Long Nature Reserve, and Pu Luông. There is a need to strengthen management through all forms and solutions.