This species has cheek pouches to carry food in while it forages. The average body mass for an adult male DeBrazza's monkey is around 7 kilograms, and for the female it is around 4 kilograms; this is a sexually dimorphic species. This species has the most robust feet of all of the guenons.
DeBrazza's monkey is primarily a frugivorous species, but seeds are also important part of the diet. This species will also eat leaves, flowers, and mushrooms. This species is diurnal and is both arboreal and terrestrial. Group sizes range from 4 to 35 individuals.
The DeBrazza's monkey has a unimale social system with a polygynous mating system. In some populations, this species tends to be more monogamous (Cords, 1987). Occasionally males try to over-take the resident male, but this does not always lead to a success. Males disperse from their natal groups.
DeBrazza's monkey gives birth to a single offspring. Females are the ones who solicit copulations from the male (Estes, 1991).
presenting: This behavior is preformed by the female to elicit copulation from the male; this pattern tells the male that she is ready for copulation (Estes, 1991).
pouting: Females do this during copulation while looking over their shoulder at the male (Estes, 1991). The lower lip is extruded forward while the lips remain closed (Estes, 1991).