Collared mangabeys are found in social groups containing 10-35 individuals. These groups contain several males, and most of them coexist peacefully and rarely display any type of dominance behavior. Each member within a group exhibits very expressive behaviour. It walks with its tail arched over its back, with the white tip held just above its head. The tail movement and the tapping of its head may provide social cues or serve as a form of communication with other members of the group. In addition, many collared mangabeys display by continuously lifting and lowering their conspicuous white eyelids.