The gray langur is a common sight in the dry deciduous forests and human settlements of India, Bhutan, Nepal, Bangladesh, Tibet, Sri Lanka, and Pakistan. One of the most common gray langur species, the northern plains gray langur (Semnopithecus entellus), is also known by other names such as the Hanuman langur, Indian langur, Bengal langur, and the sacred langur.Hanuman langurs belong to the group of Old World monkeys and the genus Semnopithecus, which also includes seven other species of gray langur such as the Kashmir gray langurs (Semnopithecus ajax), the Madras gray langur, or the tufted gray langurs (Semnopithecus priam), Tarai gray langurs (Semnopithecus hector), the Nepal Gray langurs (Semnopithecus schistaceus), the black-footed gray langurs (Semnopithecus hypoleucos), the Nilgiri langurs (Semnopithecus johnii), and the purple-faced langurs (Semnopithecus vetulus)....