There is no whorl on top of the head. The crown patch is surrounded by a black or white band that is continued behind into a neck patch. This gradually leads into a black line along the middle of the back that extends to the tail. The tip of the tail of C. torquatus is paler than the rest of the tail. A conspicuous cheek beard is present.
Mangabeys have an oval-shaped head with a fairly long muzzle.
Large cheek pouches are present and constantly used. At least one species of mangabey, C. albigena, has a throat sac that gives resonance to its calls. This sac is small in the female but large in the male. For many years little was known of the life history of this genus, but several recent investigations have improved our knowledge. C. albigena was entirely arboreal, while C. torquatus was partly terrestrial.