Sex-dependent habituation to novelty in rats

Male and female rats were familiarized with one-half of an exploration box for 30 or 60 minutes. When later tested, females showed higher preferences for the other novel half than males. Females also showed higher levels of rearing and ambulation. No sex differences were evident for grooming, freezing or defecation. The results were interpreted as females having habituated to the forced-exposure novelty of the familiar half of the apparatus more rapidly than males when the familiarization period was relatively short. With a longer period, males would have had more time to reach a similar level of habituation to that attained by females familiarized for 30 minutes. Relationships between novelty preferences and both rearing and ambulation as indices of exploration were also discussed in the light of significant correlations for males only.