The genus Trachypithecus is a group of Old World monkeys (Family Cercopithecidae) also known as lutungs or leaf eating monkeys. Old World monkeys are found in Asia and Africa (with extinct species from Europe preserved in the fossil record). As indicated by the name, Trachypithecus species subsist on a diet of leaves. They are residents of Asia’s rainforests, inhabiting the canopy in groups of five to twenty members, each troop led by an adult male with the duty of guarding the females, youngsters and troop territories. With a diet made up of leaves, fruits and flowers, these monkeys have developed specialized multi-chambered stomachs to digest tough vegetable matter.

The Nilgiri Langur (Trachypithecus johnii) is endemic to the Western Ghats, found in the evergreen, semi-evergreen, moist deciduous, montane evergreen and riparian forests of the mountains stretching between Srimangala (in Karnataka, to the north) and Aramboli Pass (in Kerala, to the south). There might be as many as ten to twenty thousand individuals. The species is categorized as ‘Vulnerable’ by the IUCN Red List of Threatened Species. It also goes by the name of Black Leaf Monkey, Hooded Leaf Monkey, Indian Hooded Leaf Monkey, John’s Langur, Nilgiri Black Langur, and Nilgiri Leaf Monkey.

Found in the states of Karnataka, Tamil Nadu and Kerala, it has fared better than the Lion-Tailed Macaque on account of its greater adaptability. But it does face a number of threats, chiefly, hunting for its skin (used to make drums), flesh and body parts (on account of certain medicinal properties associated with them). The Nilgiri Langur’s habitat is also being impacted by clearing of forests in the Western Ghats (for agriculture and mining). Some become part of the local pet trade. Others end up as road kill. While it is doing much better compared to many other endemic species of South India, much more could be done to help this elusive primate species.

The closest relative of the Nilgiri Langur is the Purple-Faced Langur (Trachypithecus vetulus) of Sri Lanka. It is an ‘Endangered’ species and lives in the rainforests of the island nation’s mountainous interior and southwest. Like its Indian cousin, the Purple-Faced Langur is an endemic species (found nowhere else in the world but Sri Lanka). Other members of the genus found in South Asia are the Phayre’s Leaf Monkey (Trachypithecus phayrei), the Capped Langur (Trachypithecus pileatus), and the Golden Langur (Trachypithecus geei). The Gray Langurs of South Asia (genus Semnopithecus) and the Surilis 0f the Malay Peninsula and Archipelago (genus Presbytis) are close relatives of Trachypithecus species.

Image Attribution: The image above, sourced from Wikimedia Commons, shows the photograph of a Nilgiri Langur resting in the rain forest canopy. The photograph was uploaded by TR Shankar Raman, a wildlife botanist with the Nature Conservation Foundation of South India.

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