Pygathrix cinerea
gray-shanked douc langur

Pygathrix cinerea is native to southeastern Asia. They are typically found in the Central Highlands of Vietnam from Quang Nam Province in the north to Binh Dinh and Gia Lai Provinces in the south. A hybridization zone exists with red-shanked douc langurs (Pygathrix nemaeus) on the northern limit of their range. (Francis, 2008; Long, 2004; Long, 2007; Nadler, 1997)

Gray-shanked douc langurs are largely arboreal, living in evergreen and semi-evergreen primary rainforests. They have been found at altitudes from 900 to 1400 m above sea level where the canopy cover is 80 to 95%. Trees in the forests where they are normally found have a diameter at breast height of 40 to 120 cm and heights of 25 to 35 m. They have also been found in some degraded forests. (Francis, 2008; Long, 2007)

The body, crown, and most of the arms of gray-shanked douc langurs are speckled light grey with a paler underside. Their shoulders, upper legs, and part of the rump are marked with white patches. The feet and hands are black while their lower legs are dark speckled grey. The bare skin on their face is yellowish brown, except for the areas around the mouth and chin which is white. Long white fur borders the sides of the face. They have an intermediate eye slant, forming a 15 degree angle from the horizontal. Their throat is white with a broad orange collar bordered by a black line which joins the black patches on their shoulders. Gray-shanked douc langur tails are nearly equal in length to their total head and body length. They are genetically similar to red-shanked douc langurs (Pygathrix nemaeus) but are considered different species due to morphological differences. Compared to black-shanked douc langurs (Pygathrix nigripes), grey-shanked douc langurs are slightly larger, but similar in size to P. nemaeus. Tail length in black-shanked douc langurs (P. nigripes) exceeds that of red and grey-shanked douc langurs by about 100 mm. Males are slightly larger than females, with an average weight of 10.9 kg in males and 8.2 kg in females. (Covert et al., 2008; Francis, 2008; Long, 2007)

Gray-shanked douc langurs typically reaches 24 years or more in captivity, lifespans in the wild are not well documented. (Lippold, 1989)

Gray-shanked douc langurs are arboreal, diurnal primates that move by jumping and brachiating. They sometimes use a suspensory posture while eating leaves from small tree branches. Their diet is mostly young leaves and this creates a need for locomotion that allows them to reach the ends of small tree branches. Gray-shanked douc langurs live in small, social groups of 4 to 15 individuals and a female to male ratio of two to one. They have also been seen alone and in large groups of up to 50. Males are the dominant sex and dominance hierarchy have been observed in captivity. Social interactions are complex, ranging from aggression to playing. (Covert et al., 2008; Primate Info Net, 2009)

Home Range

The home range size of gray-shanked douc langurs is not reported in the literature.

Gray-shanked douc langurs communicate through sound, touch, and vision. Growls can be used as warnings or threats to the other members of the group. Twitters are softer sounds emitted when the animal is being submissive. Tactile communication includes grooming and sparring. The purpose of grooming is to remove parasites and strengthen bonds between group members. In groups with more than one male, females are more likely to groom males. Grooming often occurs just before resting for the night. Sparring is an aggressive behavior and involves slapping, pulling, and grabbing. Visual forms of communication include a variety of postures and facial expressions such as play face, grimace, stare, and a sexual display. Play face is used in play with another member. A grimace is observed as part of submissive behavior towards another member. The stare conveys curiosity or aggression. The sexual display is when the female presents herself to a male signaling that she is ready to copulate or a male signaling to a female by facial movements that he is ready to copulate. (Primate Info Net, 2009)

Gray-shanked douc langurs are mostly folivorous. However, they also eat plant buds, fruit, seeds, and flowers. They seem to prefer young, tender leaves and fruits that haven’t ripened. They also don’t drink water, but get the water they need from the food that is consumed. Group members may share food. ("Southeast Asian Mammal Databank", 2008; Primate Info Net, 2009)

The main predators of gray-shanked douc langurs are humans. This species is hunted by humans and their habitat is destroyed for logging and agriculture. Gray-shanked douc langurs have also been observed responding to hunters by hiding in the trees instead of fleeing, which can make them an easy target for skilled hunters. Natural predators have not been reported, but are likely to be large raptors or southeast Asian cat species. (Nadler, 1997)

Gray-shanked douc langurs may disperse seeds of the fruits they eat by excreting undigested seeds in their feces. (Primate Info Net, 2009)

Gray-shanked douc langurs have no known negative effect on humans.

Gray-shanked douc langurs are used for food, traditional medicine, and in pet trade. However, these monkeys are critically endangered and these activities are illegal in most areas. (Nadler, 2001)

The IUCN Red List of Threatened Species classifies this species as being critically endangered and the population trend as decreasing. This is due to hunting and habitat destruction along with other circumstances. In the past, this species was listed as endangered in 2003 and data deficient in 2000. Gray-shanked douc langurs are one of the primates in "Primates in Peril: The World’s 25 Most Endangered Primates." It is estimated that there are only about 700 individuals left. The Vietnam War also had a large negative impact on this species. (Mittermeier et al., 2007; Ngoc Thanh et al., 2008; Primate Info Net, 2009)

Pygathrix cinerea was described in 1997 on the basis of newly discovered individuals in central Vietnam. (Konstant and Nadler, 2005)