Mechanisms of Individual Discrimination in Hamsters

Abstract

The capacity to discriminate between individuals has been demonstrated in a variety of animal species (see Halpin, 1980, for a recent review). Among mammals, the cues that have been studied most frequently as sources of individually distinct information have been olfactory; for example, mice, rats, gerbils, dogs, wolves and mongooses all have been shown to be capable of discriminating between the odors of different individuals of the same species (Bowers and Alexander, 1967; Carr et al., 1970; Halpin, 1976; Brown and Johnston, this volume; Rasa, 1973). In most of these studies it is the capacity to discriminate between individuals that has been demonstrated, either in a discrimination learning task or in an habituation-dishabituation paradigm. Neither of these tasks demonstrate that animals actually use individual discrimination in their normal social interactions. The habituation paradigm is preferable in this regard, since the animals tested in this type of task do spontaneously notice and pay attention to differences in the odors of individuals (e.g., see Brown and Johnston, this volume). One situation in which functional use of individual discrimination has been repeatedly demonstrated among mammals is the recognition of young in a variety of ungulates, in which both odors and vocalizations have been shown to be important (Klopfer and Gamble, 1967; Espmark, 1971).