The northern plains gray langur (Semnopithecus entellus), also known as the sacred langur, Bengal sacred langur and Hanuman langur, is a species of primate in the family Cercopithecidae.
The northern plains gray langur belongs to the genus Semnopithecus along with the other Indian langurs. The southern plains gray langur was once classified as a subspecies of S. entellus, i.e., S. entellus dussumieri and later regarded as a separate species, i.e., S. dussumieri, but is now regarded as an invalid taxon. Most of the specimens that had been regarded as Semnopithecus dussumieri fall within the revised range of Semnopithecus entellus.
The fur of adults is mostly light colored, with darker fur on the back and limbs, and the face, ears, hands and feet are all black. Infants are brown. Body size excluding tail ranges from 45.1 cm (17.8 in) to 78.4 cm (30.9 in) long, and the tail length is between 80.3 cm (31.6 in) and 111.8 cm (44.0 in). Adult males weigh between 16.9 kg (37 lb) and 19.5 kg (43 lb) while adult females weigh between 9.5 kg (21 lb) and 16.1 kg (35 lb).
The range of the northern plains gray langur covers a large portion of India south of the Himalayas south to the Tapti River and the Krishna River. It is thought to have been introduced to western Bangladesh by Hindu pilgrims on the bank of the Jalangi River.
