Sex matters in echoacoustic orientation: gender differences in the use of acoustic landmarks in Phyllostomus discolor (lesser spear-nosed bat).

Sex-specific differences in orientation strategies are well known for several rodent and primate species with females relying more on landmarks when it comes to visually guided orientation, whereas males preferentially use Euclidean cues. We used the echolocating bat Phyllostomus discolor for a behavioural study on gender differences in the use of acoustic landmarks. The experimental animals (6 males, 6 females) had to learn and perform a simple orientational task, firstly in the absence of landmarks and subsequently in the presence of four acoustic landmarks of which one was occasionally removed during the critical experiment. The results presented here show that gender differences in the use of acoustic landmarks exist in P. discolor, which supports our hypothesis that the phenomenon is independent of the modality that is used to sense the environment during orientation. Therefore, our findings allow for the prediction of similar phenomena in other acoustically orienting mammals. Interestingly, due to the specific ecology of P. discolor, our results partially contradict the evolutionary theories on gender-specific orientation, as will be discussed. Finally, we consider our finding as being one of several important steps toward establishing bats as a new model organism in neuroscientific studies on allocentric spatial cognition in mammals.