Responses of male hamsters to the ear gland secretions of conspecifics.

The behavioral responses of sexually experienced males toward anesthetized conspecifics were examined. Males directed more mounts and spent significantly more time investigating the ears and genital region of castrated males and diestrous females than intact males. Castrated males were treated in a similar manner to females, suggesting that the absence of an androgen-dependent factor(s) renders an animal more sexually attractive. Males were also administered paired preference tests in which they investigated the odors from the ear glands of diestrous females, castrated males, and intact males. Subjects spent significantly more time investigating the odors originating from ear glands of females and gonadectomized males than intact males. There was no significant difference in the amount of time males spent with the ears of castrated males and diestrous females. These experiments demonstrate that sexually experienced male hamsters can utilize odors associated with the ears to discriminate the gender of conspecifics.