Gonadal testosterone and perineal sniffing behavior of the male rat

Social-investigatory responses of intact and castrate male and female rats were observed when initially exposed to a novel conspecific. Mature males castrated prepuberally at 1, 10, or 30 days of age engaged in normal social-investigatory behavior with the exception that anogenital sniff frequencies were comparable to that of intact or castrated females and significantly less than that of intact males; postpuberal castrates failed to differ from intact males. When treated with exogenous testosterone, anogenital sniff frequencies of prepuberal castrates increased significantly. The results confirm the hypothesis that perineal sniffing behavior is androgen dependent and suggest that androgens amplify the specific behavior pattern that serves to increase sensitivity to biologically significant olfactory stimuli of social origin.