How do Vervet Monkeys communicate and are they aggressive?

Mutual grooming forms a very important part of the social structure of a troop. Many vocalisations have been recorded, with contact calls including chirps, grunts, chatters and barks. Alarm calls include low, loud barks and screams. Different threats result in different calls, such as a high pitched chatter when encountering a snake, a short, tonal call for a leopard and staccato grunts when observing raptors.

Aggression is shown by looping the tail over the body, threat is displayed with a direct stare and a greater threat is shown by raising the eyebrows to reveal the contrasting pink of the eyelids. Other threatening displays include an openmouthed gape, shaking of branches, jumping up and down, slapping the ground or bobbing the head up and down.

Dominant males sometimes intimidate subordinates by holding the tail erect to display the blue scrotum, red perianal region and white fur between the scrotum and perianal region, a display known as the red, white and blue display.