The Life of the Langurs (Presbytis entellus: Dufresne)
The Langurs found throughout South East Asia including Southern China and the Indian subcontinent are mostly tree dwelling but some may live on rocks and cliffs. They may also occupy a wide range of ecological niches and dwell in tropical rain forests to the harsh Himalayan foothills. This group was filmed by Dr. Yashpal Singh at Ranthambore National Park, India in October 2023.
Leopards are their greatest enemies. The alarm calls of the Langurs on sighting a tiger or leopard are well known in helping locate tigers and leopards. A warning cry from one langur will send the entire troop bolting.
Many apes and monkeys can communicate their feelings of pleasure, anger or fear through vocal utterances which are well understood by the troop. They sleep on the upper forest canopy to avoid predation. The robust social set up amongst the members of each group gives them maximum advantage in saving them from dangers, providing living room, food and opportunities for reproduction. The intricate social life increases the chance of survival.
Each troop occupies its own territory ranging from 1.3 to 13 sq. Kms. Predominantly Batchelor Groups have a higher range. The core area is located near the roosting tree. Adult males are the leaders. A female may become sexually active at about the age of 3.6 years and bears off springs every two years (some records mention every year).
In the wild males can live for about 18 years and females for about 30 years. Males can only remain leader of a harem for three to four years after which they are thrown out by the Batchelor groups of males.
They are vegetarians, feeding occasionally on Insects. Interestingly, unlike macaques and baboons, langurs do not have the cheek pouches for storing food but the stomach consists of three separate pouches with one of these, a special pouch for receiving partly chewed food.
Langurs love to spend the hottest hours of the day dosing and resting in some sheltered grove or tree bordered water course. The langur is a more peaceful and sober animal than the Rhesus.
A very important part of inter communication is ‘Grooming’ or ‘fur picking’. This was earlier believed to be for a hunt of fleas or lice or fragments of skin secretions but it is not generally so. Grooming provides a gentle stimulus or caress which may involve courtship too. Its repeated indulgence suggests a powerful bond between members of the group. This clip describes the process of grooming in all its interesting details including a focused and detailed scrutiny of all the body parts offered for grooming. It almost appears that one Langur was doing a medical examination of the other. Grooming of males by females also gives the females an opportunity to feed side by side of the males.
Females may be more engaged in grooming than males. Younger individuals may be involved less. Dominant langurs groom one another and receive grooming more often than subordinate Langurs.
Langurs are listed as a species of “Least Concern” on the IUCN List. It was previously listed as near Threatened.
Acknowledgements-Dr. Yashpal Singh, Mrs. Neena Singh, Manoj Kumar Yadav