Eco-ethological aspect of the Hanuman langurs were studied from September, 2012 to December 2013 at the various troops sites in Chitrakoot. For this study four bisexual troops were monitored to study the group size, age-sex composition and other ecological behavior patterns. In present investigations it was recorded that they feed on natural and provisioned food. Around thirty plant species were identified as food which ratifies their folivorous nature. Major circadian activities of Hanuman langur such as resting, walking, sleeping, feeding, grooming, mating and playing was also recorded. Inspite of a round the year breeding, observations on decreased birth rate in the Semnopithecus entellus envisage bad indicator for future of this endangered species was also discussed.