A Test of Olfactory Sex Discrimination in Big Brown Bats (Eptesicus fuscus)
Effective communication is essential for the maintenance of cohesion in bat colonies, which can contain thousands of individuals. Several studies have shown that odour cues can provide information about the species, colony membership, and identity of a bat; however, the extent to which these odour cues can convey information about sex remains unclear. Because big brown bats (Eptesicus fuscus) live in mixed gender colonies during mating season, the ability to differentiate between sexes is necessary to locate a mate. The present study aims to examine whether E. fuscus can discriminate between sexes using only olfactory information.
Adult E. fuscus were recorded moving freely within a maze that contained scents obtained from a male and a female of the same species. One group of subjects was habituated to the maze prior to experimental trials, whereas a second group was not habituated prior to the experiment. The exploratory behaviour of the bats in the maze and the proportion of time spent near each scent were used as indicators of preference toward the odour of a particular sex.
Results provided no evidence that E. fuscus were able to discriminate between sexes using olfaction, as both male and female test bats did not show a preference for the scent of one sex over the other. Interestingly, non-habituated animals explored the maze to a greater degree and were more likely to approach a stimulus scent than those that had been habituated. This finding has important implications for the design of future behavioural studies involving bats.