Diana guenons are arboreal and live in the high canopy of forests where they forage during the day for fruit, leaves and insects (4) (6). They occur in fairly large groups (5 to 50 individuals), which are composed of a single male with up to ten females, and their young (2) (5). It is well known that living in groups is the primary defence strategy amongst diurnal primates, as there is safety in numbers, and individuals can alert others when they sense danger (5). However, Diana guenons seem to have perfected this behaviour and are so alert that other primate species have come to live with them to benefit from their watchful eyes (5). Olive colobus (Procolobus verus) in the Tai National Park, Cote d’Ivoire, are known to form permanent attachments with Diana guenon groups, and other species, such as the red colobus monkey (Piliocolobus badius), form more transient bonds (5). These relationships are successful because, while they benefit from the greater group sizes, they do not suffer from competition for food as each species has a slightly different niche and food source (5).
Breeding in this species is thought to occur year round, with females giving birth to a single offspring after a six month gestation period (4) (6).