Gray langurs or Hanuman langurs, the most widespread langurs of South Asia, are a group of Old World monkeys constituting the entirety of the genus Semnopithecus. All taxa have traditionally been placed in the single species Semnopithecus entellus.
Gray langurs are large and fairly terrestrial, inhabiting forest, open lightly wooded habitats, and urban areas on the Indian subcontinent.
The Hanuman Langur is adapted to eating tough food which others find indigestible. They can even eat seeds with high levels of the toxins like strychnine (Strychnos nox-vomica) and distasteful vegetation avoided by other creatures. They feed mainly on leaves and other vegetation but also search the ground for fallen fruit and nuts. They also snack on insects, fungi and tree gum. They may even eat soil or stones, probably for minerals to help detoxify their food. They are thus found in a wide range of habitats from the plains to forests.
With long strong limbs, the Hanuman Langur runs fast on the ground on all fours, and climbs well and is agile among trees, its long thin tail providing balance. Their horizontal leaps average 3-5m but can reach up to 13m with some loss of height. But it is more nervous on the ground, and will flee to the trees when in danger. They usually only move on the ground when trees are scarce. They forage during the morning and late afternoon. The troop returns to the same sleeping tree every night. They sleep at the ends of branches, where it's hard for a large predator to get at them. Sometimes, they sleep in caves.
Hanuman is the Hindu god of healing and worship and in many parts of India, the Hanuman langur is considered sacred. The Hanuman langur often travels in the company of Indian holy men. Many Hindus leave them unmolested and even permit them to freely plunder their grain shops. However, this has made the langurs fearless. During food shortages, humans often retaliate. They are also threatened by habitat loss. There are an estimated 230,000 Hanuman langurs left in India.