Species Name: Trachypithecus hatinhensis
The Hatinh langur (Trachypithecus hatinhensis) is a critically endangered Old World monkey found in the limestone forests of Vietnam, particularly in Quảng Bình province. Contrary to their common name, the Hatinh langur is not known from the province of Hà Tĩnh.
Species Name: Nomascus annamensis
The northern buffed-cheeked gibbon (Nomascus annamensis) is a species of crested gibbon recently discovered in Vietnam, Laos, and Cambodia. Northern buffed-cheeked gibbons live almost exclusively in trees and rarely leave the canopy's comfort and safety.
Species Name: Nomascus leucogenys
The northern white-cheeked gibbon (Nomascus leucogenys), also called the white-cheeked gibbon, is an endangered species of gibbon endemic to Southeast Asia. Like other members of its genus, both males and females have unusually long arms, even for gibbons, with arms 1.2 to 1.4 times the length of their legs.
Species Name: Nomascus nasutus
The eastern black-crested gibbon, also called the Cao-vit crested gibbon or Cao-vit black-crested gibbon, is a gibbon native to northern Vietnam and southeast China. Eastern black-crested gibbons are found in social groups consisting of females, juveniles, infants, and sometimes males.
Species Name: Nomascus gabriellae
The southern yellow-cheeked gibbon, also known as a golden-cheeked gibbon, buffed-cheeked gibbon, red-cheeked gibbon, southern yellow-cheeked crested gibbon, or golden-cheeked crested gibbon, is a species of gibbon endemic to Cambodia, Laos, and Vietnam.
Species Name: Nomascus concolor
Black-crested Gibbons are mainly found in southern China (Yunnan) and some distribution areas in northwestern Laos and northern Vietnam. Black-crested gibbons exhibit sexual dichromatism, with the male being entirely black, while the female is yellowish or tan in color with variable black markings.
Species Name: Macaca leonina
The northern pig-tailed macaque (Macaca leonina) is a macaque species in the Cercopithecidae family. Typical of this group of Old World monkeys, northern pig-tailed monkeys are gregarious, living in social groups of 9-81 individuals.
Species Name: Trachypithecus francoisi
The François langur, also called the white side-burned black langur, François leaf monkey, or Tonkin leaf monkey is a species of Lutung and the type species of its species group. The François langur is among the least studied langur species.
Species Name: Pygathrix nemaeus
The red-shanked douc langur is an Old-World monkey species that is one of the most colorful primates. Red-shanked douc langurs are genetically similar to gray-shanked douc langurs; however, they are considered a different species due to their different biological characteristics.
Species Name: Macaca assamensis
The Assam macaque, also known as Assamese macaque, is a macaque of the Old-World monkey family endemic to South and Southeast Asia. Assam is another state in India. Eating everything from fruits to 55 types of flowers, leaves, seeds, and bark, these macaque monkeys adapt their diet to suit their habitat.
Species Name: Trachypithecus margarita
The Annamese langur is another Old-World monkey in the subfamily Colobinae. Annamese langurs are covered in thick, gray fur. They have dark faces, and the space around the eyes is pale and forms a ring, often in the flesh. Trachypithecus margarita is a monotypic species as it has no subspecies.