Even when only a small portion of the body is visible through the foliage, a monkey can tell who is who. Excitement level is indicated by tail position and coloration. Long tails are certainly for balance and steering but they also indicate mood and status. Heightened excitement level is easily recognized in skin color, which is enhanced by blood flow. In humans it is called a blush.
Guenons have large, well-developed cheek pouches.
All guenons are diurnal. Territorial defense is not left to the males, the whole troupe defends the boundaries, the females tending to be the fiercest in group conflicts. Male guenons are not nearly as aggressive as their near relatives, the macaques. Monkeys such as baboons and macaques use many facial expressions to communicate with each other. The speed and direction of these movements communicate specific meanings.