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.
Habitat Mountain gorillas inhabit the montane cloud forest of the Virunga range. There is continuing political pressure to convert the remaining gorilla reserves into areas for farming or commercial use. Due to the high population density, many people feel that the land would be better put to commercial use. This is due both to habitat destruction and severe poaching pressures. The civil war occuring in the region they inhabit has only added to their plight, increasing mortality through accidents and the breakdown of patrol units against poachers.