Primates are the easiest mammals to see in Fazao. Olive baboons travel in large noisy troops through both forest and savanna; patas monkeys, with their distinctive russet coats, prefer the open grasslands; vervets are scattered everywhere; and the more secretive Campbell's and white-thighed colobus monkeys live in the gallery forests along the rivers.
The colobus, in particular, is worth watching for — their black-and-white markings flash through the canopy as troops move and feed. Walks along the Mô and Anié rivers, very early in the day, give the best chance. Rangers know which sections of forest currently hold the most active troops.