While some guenons stray into the temperate climates found in southern Africa or high altitudes, they mostly thrive in tropical conditions. To survive, these monkeys need a temperature of at least 70°F (21°C). They are most comfortable when the temperature is between 75–85°F (24–29°C).
Guenons live primarily in the tropical rainforest belt in Africa to the south of the Sahara Desert, but a few species have adapted to the forests along principle African rivers. Furthermore, one species—the grass-monkey-thrives in the open savanna and spends a significant amount of time on the ground.
Overall, the forest-dwelling species prefer to live deep within the shelter of forests. However, they often prefer to inhabit different types of forests. For example, some species like to live high in the canopy and rarely come down to the lower branches or the forest floor. Other species are very active near the ground and commonly leave the trees. Interestingly, guenon distribution is heavily influenced by varying conditions. Population shifts sometimes cause migrations to areas previously uninhabited by guenons.
The savanna-dwelling species of guenon, the grass monkey, inhabits areas near the boundaries of rain-forests. They live only near running water and tend to avoid open areas and forest interiors. They prefer certain trees, and are reportedly fond of the fruit of the wild fig tree. When they are pursued, they have been seen pressing themselves against tree branches for camouflage. Typically, they live in groups of 20-50, each group usually limiting its activities to a specific territory.