With the alias of Flat-top Monkey, it belongs to the Cercopithecidae family of Primates order. Its scientific name is Macaca nemestrina (Latin) Macacanemestrina, or Pig-tailed Macaque (English).

It body stretches 54 to 62 centimeters long, and tail-length is less than a quarter of body-length. It is brown or dark brown all over. The short vertex hair is radiately arranged into a tan flat top, like a cap. Its cheek sides have short palpus. The tail is short and thin, often curled like a pigtail, with sparse tail hair, hence it gets the name of Pig-tailed Macaque. Its belly hair is hoar.

Pig-tailed Macaque inhabits in tropical and subtropical forests or coniferous forests at lower elevation, leading a tree dwelling life and feeding on wild fruits, seeds, as well as insects and birdies. It moves about in groups in daytime, led by a strong male monkey. The gestation of female monkey is about 171 (162 to 186) days, one baby per fetus, with a suckling period about three months. It grows to sexual maturity at the age of 4. Under breeding condition, its lifespan can reach up to 26 years.

It is distributed in the southwest of Yunnan Province and the southeast of Tibet Autonomous Region, with nearly 1,000 heads left.