The sexual attractiveness of male rats: olfactory and behavioral components

Female rats are more attracted to intact than to castrated males. In this study, we compared the approach of female rats, in a straight runway, to (1) castrated males, which neither smell nor behave like intact males, (2) castrated males treated with dihydrotestosterone (DHT), which smell like intact males but behave like castrate males, and (3) castrated males treated with DHT and estradiol benzoate (EB), which both smell and behave like intact males. It was found that females ran faster to DHT males than to the castrate controls; and faster to the DHT-EB group than to the DHT group. Thus the odour and the sexual activity of male rats are independent effective sources of incentive to females.