The colour of the young, born singly after about 168 days gestation, differs from the adults and possibly serves to arouse maternal protectiveness. The Hanuman langur, typical of this genus, is almost black when new-born and grey, tan, or brown when adult. Regarded as sacred in India, it is allowed to roam at will in villages and temples, raiding crops or helping itself to the stores of merchants. The Hanuman langur lives in bands of about 20-30 individuals. The males have clearly marked dominance positions, but females have no fixed status.
Mothers are protective but allow other females to help care for the young.
The Red Data Book lists the douc and pigtailed langurs as endangered species. Several other species are becoming rare.