Two groups of 4 feral rhesus monkey mothers and their infants were observed for 6 months. Primiparous and multiparous mothers were strikingly similar on most measures of positive maternal behavior as were their infants on the basic infant-mother categories. The peer-directed social behavior of the infants of the primiparous and multiparous mothers of the present experiment and of 4 surrogate raised infants was considered with particular emphasis being given to the development of sex differences and sexual behavior. The similarity in the social behavior of surrogate and mother-reared infants was attributed to multiple compensating bases for the development of social behavior in the rhesus monkey.