Capped langurs have dark grey to black fur on their backs and creamy white or golden yellow fur on the belly. Their face is black and the crown is dark grey in color. The ears, palms, and soles, are black in color. The rump and the insides of the thighs are light blue, and are more brighter in males than females. These monkeys have very long tailes that are longer than the head and body combined.
Capped langurs are found in Bangladesh, Bhutan, India, and Myanmar. Their natural habitat is subtropical or tropical dry forests.
Capped langurs are arboreal and diurnal creatures. They wake up early in the morning but remain in their sleeping sights and when the sun has fully risen they may move to higher branches to bask in the morning sun before foraging. They usually forage in the morning and late afternoon. In the evening they will find a suitable sleeping tree and will change the tree every night. Each individual sleeps in a tree alone, except for mothers with their infants. Capped langurs are very gregarious by nature. Each troop consists of 2-14 individuals led by a male. There are also solitary males and small bachelor groups of young males. There are also multi-male, multi-female groups, in which females lead the group and control direction, while males are slower and often stay behind and stop eating when the group moves on. Capped langurs are very playful and like to spend their time socializing through grooming and face-to-face hugging. In order to communicate with each other, these monkeys use growls, alarm barks, a distress call that sounds like "eeeeh" and the nouk call that is produced by adults when the group is moving through the trees. Infants produce whistle-trills when they are carried by their mothers and an infant scream that is heard when the baby langur is left alone.
The mating system in Capped langurs is suggested to be polygynous as each group consists of a single dominant male and many females. This system indicates that a dominant male can mate with all the females in his group. The breeding season occurs in September-January. Females give birth to a single infant every two years. The gestation period lasts around 200 days. The first two months after birth the infant spends with its own mother or with another female in the group (allomother). When the young grows up a little it is allowed to play with the other infants. When the infant is one year old it still spends some time with the mother during the day and is nursed by her in the evening. However, the young is able to forage by itself with the rest members of the group at 10-11 months.
Capped langurs are threatened by the destruction of habitat due to jhum cultivation, timber and firewood harvests, and other development that causes the loss of trees. Another big threat to these primates is hunting for meat and other parts, for traditional “medicine”, for sport and are traded as pets.
The IUCN Red List and other sources don’t provide the number of the Capped langur total population size. Currently, this species is classified as Vulnerable (VU) on the IUCN Red List and its numbers today are decreasing.