Olfactory discrimination of estrous condition by the male golden hamster (Mesocricetus auratus).

After repeated exposure to receptive and nonreceptive females, male golden hamsters were tested for olfactory preferences in a four-choice olfactometer. Males discriminated between the odor of anesthetized females in different stages of their estrous cycle when the airstreams carrying the stimulus odors were diluted. Previous failures to demonstrate such an ability were probably due to ceiling effects resulting from laboratory testing. Males preferred the odor of females on the day before receptivity (a day coincident with maximal scent marking by the female) and least preferred the odor of females on diestrus-1 (the day on which females attacked and chased males during pretesting encounters). Detection and quick response to an impending estrus would be especially important for males of a solitary and promiscuous species in which there is a first male mating advantage.