Whole communities have been known to be killed off by stronger neighboring communities as they take over the range. Communication is complex, involving a variety of facial expressions, gestures and vocalizations. Captive animals have even learned to communicate with humans using sign language. Mutual grooming is essential in maintaining friendly relationships, though it is also often used to gain favors. Males stay in a natal group and travel together.
Females emigrate to new groups.
Older females are more popular with males than younger individuals who often have to leave the community, either temporarily or permanently, in order to mate. Breeding takes place throughout the year with the estrous cycle lasting about 36 days. There is a minimum interval of 3 years between births, but 5-6 is more common if the young survives. A female can give birth yearly if the infant is taken away within the first few months of life. For the first 3 months of life the infant is cradled as the mother sits.