The unrestricted adult social and nonsocial behavior of albino rats isolated from 21 to 70 days of age was compared with the behavior of rats receiving normal social experience. Isolated animals exhibited aberrant self-manipulative behaviors during the period of isolation, and both isolate-reared males and females were more aggressive than their group-reared counterparts. The hypothesis that females are buffered against the effects of social isolation received little support. Numerous gender differences and differences in the gender of the object of social response were found for both isolate- and group-reared rats. Gender and Rearing Conditions were relatively independent influences on behavior with few Gender x Treatment interactions reaching significance.