When food is plentiful, groups may merge into large but temporary associations of up to 50. All species associate freely with other primates, mainly guenons . Their home range is generally small. When the female is ready to breed, her buttocks swell as a visual signal to the males. The first shipment of these primates were labelled as coming from Mangabe, a port in Madagascar.
Mangabeys are very vocal and their calls are often the first and only indication of their presence.
Troop members frequently call in chorus. In some species, males have a throat sac which amplifies their call, females have smaller sacs. Their repertoire includes shrieks and howls. This call is only made by mature males to announce the troop's location and territorial and thus space out the mangabey groups and avoid potentially dangerous encounters. They also use a wide variety of facrial expressions and body postures.