Facilitation of intermale aggression in mice through exposure to receptive females

Examined intermale aggression after different exposures to receptive females. In Exp I, socially isolated or grouped CD-1 and Swiss-Webster mice each confronted a target male after either no exposure to or 3 intromissions with an estrous female. High levels of aggression were observed in isolated males after exposure to a female, provided the female was removed when the target male was introduced. In Exp II, variation of duration and quality of exposure to females indicated that aggression increased with more advanced prior sexual activity. In Exp III, sexual activity was not greatly influenced by prior aggressive activity. These data suggest a preparedness to fight following sexual activity, but a prepotence of sexual activity over aggression. (31 ref)