S. schistaceus S. ajax S. hector S. entellus S. hypoleucos S. johnii S. priam S. vetulus Semnopithecus is a genus of Old World monkeys native to the Indian subcontinent, with all species with the exception of two being commonly known as gray langurs.

Members of the genus Semnopithecus are terrestrial, inhabiting forest, open lightly wooded habitats, and urban areas on the Indian subcontinent.

Externally, the various species mainly differ in the darkness of the hands and feet, the overall color and the presence or absence of a crest.

[4][5] Typically all north Indian gray langurs have their tail tips looping towards their head during a casual walk whereas all south Indian and Sri Lankan gray langurs have an inverted "U" shape or a "S" tail carriage pattern.

[5] The larger gray langurs are rivals for the largest species of monkey found in Asia.

They will also make bipedal hops, climbing and descending supports with the body upright, and leaps.

[9][10] It has been suggested that the Semnopithecus priam thersites is worthy of treatment as a species rather than a subspecies, but at present this is based on limited evidence.

[11] During a study based on external morphology and ecological niche modelling in Peninsular India six main types were found, but continued to label all as subspecies.

Coat color is highly variable, possible due to phenotypic plasticity and therefore of questionable value in species delimitation.

[9] A possible explanation for this is that the T. pileatus species group is the result of fairly recent hybridization between Semnopithecus and Trachypithecus.

[27] The entire distribution of all gray langur species stretches from the Himalayas in the north to Sri Lanka in the south, and from Bangladesh in the east to Pakistan in the west.

[5] The bulk of the gray langur distribution is within India, and all seven currently recognized species have at least a part of their range in this country.

[2][3] They can adapt well to human settlements, and are found in villages, towns and areas with housing or agriculture.

They sleep during the night in trees but also on man-made structures like towers and electric poles when in human settlements.

However, unlike some other colobines they do not depend on leaves and leaf buds of herbs, but will also eat coniferous needles and cones, fruits and fruit buds, evergreen petioles, shoots and roots, seeds, grass, bamboo, fern rhizomes, mosses, and lichens.

Leaves of trees and shrubs rank at the top of preferred food, followed by herbs and grasses.

Non-plant material consumed include spider webs, termite mounds and insect larvae.

In one-male groups, the resident male is usually the sole breeder of the females and sires all the young.

[52] Females signal that they are ready to mate by shuddering the head, lowering the tail, and presenting their anogenital regions.

[55] Infanticide is more commonly reported in one-male groups, perhaps because one male monopolizing matings drives the evolution of this trait.

Nevertheless, infanticide does occur in these groups, and is suggested that such practices serve to return a female to estrous and gain the opportunity to mate.

[57] Infants are born with thin, dark brown or black hair and pale skin.

[63] India has laws prohibiting the capturing or killing of langurs, but they are still hunted in some parts of the country.

This happens even in protected areas, with deaths by automobile collisions making nearly a quarter of mortality in Kumbhalgarh Wildlife Sanctuary in Rajasthan, India.

[67] Because of their sacred status and their less aggressive behavior compared to other primates, langurs are generally not considered pests in many parts of India.

Despite this, research in some areas show high levels of support for the removal of langurs from villages, their sacred status no longer important.

[69] Langurs stealing and biting people to get food in urban areas may also contribute to more persecutions.