Mandrills forage mainly on the forest floor and travel constantly as they forage, covering 3-5 miles a day. Sexually mature at about 5 years of age. Some sources say that females are sexually mature at 3 years. The gestation period is 5-6 months. There appear to be peak breeding times with births 1 or 2 years apart.
Mandrills give birth to a single offspring.
Daughters stay with the mother's troop while sons usually leave their natal troop when they reach adolescence. The mandrill communicates in several ways. Visually, the bright colors of the males help other troop members locate him. The mandrill also uses several vocalizations. A 2-phase grunt or roar by the lead male, mobilizes the troop for traveling.