Weaning often doesn't occur until three years of age, and juveniles may remain with mothers for years after that. Females are sexually mature by 10 years of age, but males are unlikely to start breeding before 15 years. Behavior The main social unit is an alpha male with a harem of females and their offspring. These groups are nonterritorial, but severe intergroup conflicts can occur when groups encounter each other and especially if a lone male contacts the group. The dominant male of a group is massive compared to the other members and they all defer to him.
Females transfer from their natal group to a new group before breeding.
This generally occurs at around 8 years of age. Often they join a lone male and start a new group, rather than join an established group and be a lower ranking female. Males often leave the natal group at around 11 years of age. Males, however, can't join an establish group, and they spend much time in solitary existence until they can gain females and begin a group of their own at age 15 or older. Grooming often occurs between females and males, or among females.