Golden hamsters recognize individuals, not just individual scents

Abstract

Abstract. If animals actually recognize individuals as unique entities they should have integrated, multi-factor representations of these individuals. This hypothesis was tested for individual recognition by scent in golden hamsters, Mesocricetus auratus. Two scents that can be used by hamsters to discriminate individuals are flank gland and vaginal secretions, scents with quite different odour qualities. In the first experiment males that were familiar with two females were exposed to vaginal secretions from one of these females during four habituation trials and then, on the test trial, were exposed to the flank gland scent of either the same female or the other female (different female). Males investigated the flank scent of the same female significantly less than that of the different female. That is, exposure of males to vaginal secretions of one female resulted in habituation to that female's flank scent, suggesting that they did so because both scents represent the same individual. A second experiment showed, as a control, that if males were not familiar with the females that provided the scents, this cross-habituation effect did not occur. Thus, the results of the first experiment cannot be explained as a result of generalization from vaginal scent to flank scent of the same individual on the basis of stimulus similarity. These results demonstrate that golden hamsters respond to individually distinctive signals on the basis of the referent (or meaning) of the signal, and suggest the existence of multi-factor representations of individuals. They also indicate the importance of higher-order, cognitive processing in the social behaviour and communication of a rodent.