| Abstract: | Small colonies of rats were established, using adult animals that had either received continuous social experience or had been isolated since weaning. Unfamiliar "intruder" rats--with or without postweaning social experience--were exposed individually to the colonies for a 21-hr. period. Behavioral observations and an assessment of the intruder's physical condition indicated that serious fighting, physical injuries, and large weight losses occurred only when an isolation-reared intruder was placed into a colony of socially experienced rats. These results demonstrate that aggression is a joint function of the rearing history of both the colony and the intruder and that social experience plays an important role in the behavioral development of this species. |
