Dwindling Population of Capped Langurs
-Dr. Arvind Singh
Capped langur is a species of Primate found in Indian sub-continent (India, Bangladesh, Bhutan and Myanmar). The scientific name of Capped langur is Trachypithecus pileatus and it belongs to Cercopithecidae family. This species of langur is most common in North-eastern India. Though sympatric with Hoolock gibbons in South Asia, it is not heavily affected by the impacts of habitat loss and is more adaptive, breeds more rapidly, and can move across fragments easily.
There are four recognized sub-species of the Capped langur; Trachypithecus pileatus pileatus, Trachypithecus pileatus durga, Trachypithecus pileatus brahma and Trachypithecus pileatus tenebricus.
Distribution Range:
Capped langur is found in Bangladesh, Bhutan, North-eastern India and North-western Myanmar. In North-eastern India Capped langurs are found in the states of Assam, Manipur, Meghalaya, Mizoram, Arunachal Pradesh, Nagaland and Tripura. South Asian populations of Trachy-pithecus pileatus sub-species are known to exist in adjacent and sometimes overlapping areas of India, Bangladesh, Bhutan and Myanmar. Various populations exist between 10 and 3,000 m in elevation.
Trachypitheus pileatus pileatus sub-species occurs in North-eastern India and North-western Myanmar while Trachypithecus pileatus durga sub-species of Capped langur occurs in North-eastern and South-eastern Bangladesh and North-eastern India. The other sub-species Trachypithecus pileatus brahma occurs in North-eastern India in Dafla Hills, north of Brahmaputra, whereas Trachypithecus pileatus tenebricus sub-species of Capped langur occurs in Bhutan and North-eastern India.
Physical Characteristics:
The Capped langur as a whole is recognized by the dark grey to black fur of the back, fading to creamy white or golden yellow on the belly. However, small differences in colouration distinguish the four sub- species of Capped langur. The cheeks have a yellow-red hue and the ears, palms and soles are black in colour.
The rump and insides of the thighs are light blue, and this colouration is stronger in males than females. Infants are creamy-white with a soft golden tinge all over. The face, ears, palms and soles are pink. Juveniles lose the glow of gold as they mature and begin to turn an ash grey and their bare skin turns from pink to black.
Capped langur has a sacculated stomach to assist in the breakdown of cellulose. The animal has enlarged salivary glands to assist it in breaking down food. The tail of the Capped langur is longer than the head and body combined.
The head and body length of adult males ranges from 68.4 to 70 cm and for adult females it ranges from 59 to 67 cm. The tail length for adult males ranges from 94 to 104 cm and for adult females it ranges from 78 to 90 cm. Males have a body mass ranging from 11.5 to 14 kg and the female body mass that ranges from 9.5 to 11.5 kg.
Habitat and Ecology:
Capped langurs are found in tropical dry deciduous, sub-tropical, broadleaf and evergreen forests providing there are many streams. In northeastern India, the Capped langur lives in tropical evergreen forests, semi-evergreen forests, tropical moist deciduous forests, subtropical broad-leaved hill forests, in bamboo forest and in plantations of Teak (Tectona grandis), Gamari (Gmelina arborea), Semul (Bombax ceiba) and Sal (Shorea robusta).
Capped langurs are diurnal, arboreal and folivorous but fruit is also a major component of the diet. The Capped langur group wakes with dawn but they remain in their sleeping trees until the sun has fully risen. Even they may simply move to higher branches with little foliage where they can bask in the sunlight before heading off to forage.
They feed mainly in the early morning and late afternoon. They spend nearly 40% of the day time feeding on leaves, flowers and fruits. Leaves contribute about 60% of the diet and they foraged on as many as 43 different plant species.
Mating takes place in the mornings between September and January. Gestation period is of 200 days and births are concentrated between December and April with majority occurring in the month of March. A single infant is born which spends the first two months of its life either with its own mother or with another female in the group known as allomother. Infants begin to forage alone at 10 - 11 months. The generation length is about 10 – 12 years.
Threats to their Survival:
Habitat loss and hunting are the two main threats to the survival of Capped langurs.
Habitat loss is due to Jhum cultivation (slash and burn agriculture), timber and firewood harvests, grazing, human settlements, roads, dams and power lines. These activities results in a loss of fruiting and lodging trees.
Capped langurs are hunted for meat as well as for traditional ‘medicine’ and for sport. The meat including that on the tail is eaten. The skin is used for knife sheaths and the fur for clothing.
Capped langurs are also caught as pets and for zoos.
Conservation:
The Capped langur has declined by more than 30% in the last 20 years making it very vulnerable in its extremely fragmented locations and it is predicted to decline at the same rate in next 20 years.
All South Asian populations of Capped langur are listed under Schedule I, Part I of the Indian Wildlife (Protection) Act 1972, amended up to 2002. Furthermore, the populations of Capped langurs are also listed on Appendix I of Convention on International Trade in Endangered Species (CITES).
The following actions are needed for the conservation of Capped langurs in India.
1. To check the habitat loss of Capped langurs.
2. To restore the degraded habitats of Capped langurs.
3. To regularly monitor the population of Capped langurs in their habitats.
4. To put a complete ban on Jhum cultivation in the habitats of Capped langurs.
5. To promote captive breeding of the Capped langurs.
6. To educate the people about the biological/ecological significance of the Capped langurs.
7. To strictly enforce the Wildlife Protection Act and CITES.
Conclusion:
It can be concluded that the Capped langur is threatened species of primate chiefly due to habitat loss and hunting. Therefore, conservation of the species is the need of the hour for the maintenance of biological diversity and ecological stability.
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Dr. Arvind Singh is M. Sc. and Ph. D. in Botany with area of specialization in Ecology. He is an dedicated Researcher having more than four dozen of published Research Papers in the Journals of National and International repute. His main area of Research is Restoration of Mined Lands. However, he has also conducted Research on the Vascular Flora of Banaras Hindu University Main Campus, India.keywords: capped langurs in india, capped langur in assam, capped langur facts, capped monkey, capped langur, golden langur, langoor in english, indian monkeys, capped langur iucn