Range

Dusky langurs come from Asia. They can be found in Malaysia, Thailand and Myanmar. They can also be found on some offshore islands.

Habitat

As an arboreal species dusky langurs live in densely forested areas. Some langurs have been sighted encroaching into human settlements. Humans destroying their habitat is one of the reasons that this species has been in decline.

Reproduction

Breeding can occur throughout the year. It appears to be concentrated between January and March in most areas though. To show they are fertile females will display a genital swelling.

After a gestation period of 145 days a single infant would normally be born. On occasion twins can occur though. These babies are bright orange so they can be easily spotted by all members of the troop.

They spend most of their day on the nipple of their mother.

After about a month they begin to go out exploring on their own. This is also when they start to try solid foods. At this point they begin to play as well.

Following 70 days of life they begin to interact with other members of the group. At this time they also begin to groom group members.

At six months of age they will begin the transition from orange to grey.

The age of weaning is unknown. It is difficult for them to wean as they need their mother to chew leaves for them and then their saliva passes the enzymes for digestion of leaves to the infant.

Sexual maturity occurs after 3 to 4 years.

Behaviour

Dusky langurs live in groups of between 5 and 20 individuals. A male will head up a group of 2 females and their offspring. Excess males leave and form bachelor groups. When a group does not have a head one will take it over and kill all of the offspring from the last male.

They make a variety of calls which are quite complex these include snorts, hoots, murmurs and squeaks.

This species is diurnal meaning they are active during the day. They tend to concentrate most of their activity towards the early morning and afternoon. Moving around their territory is done by climbing, leaping and running along the branches on all four hands.

As a highly territorial species langurs will work to remove any intruders from their territory. If making loud noises doesn’t work they are not afraid to us force to remove these intruders.

Potential predators of this species include snakes and large birds of prey though they are unconfirmed. Humans are also a predator of this species.

Quick facts

Other names for the dusky langur include the spectacled langur, dusky leaf monkey and spectacled leaf monkey.

The word langur is derived from the hindu word for long tailed.