Meder, A. 1985. Integration of hand-reared gorilla infants in a group. Zoo Biology 4, 1-12.

Zoo-born gorilla infants could best be introduced into a group when about 1.5 to 2 years old; when younger or older, social integration becomes more difficult. An introduction to adult females in a small cage until strong social relations are formed leads to a smoother social integration in the whole group afterward and takes less time than socializing the infants to juveniles. Allowing the infants to explore the group's main enclosure alone and before they join the group permanently leads to better spacial orientation for them and helps to lessen their uneasiness in the new social situation. Providing the infants with a shelter within the group's enclosure, which gives them access to the group but is inaccessible to the adults, reduces tension and thus aggression toward them. Abnormal behavior already developed in the nursery seems to slow down the social integration considerably.