Hearing thresholds in the bat Carollia perspicillata vary by sex but not age

Abstract

Bats rely heavily on auditory perception for critical behaviors including navigation (echolocation) and conspecific communication. However, there is little information on the impacts of age and sex on the bat auditory system. Here, we used auditory brainstem response recordings to measure auditory thresholds in Carollia perspicillata (Sebas short-tailed bat). We did not detect an age-related threshold shift at the age range examined (1-8 years old), suggesting that bats may be relatively resistant to age-related hearing loss. We had considerably more young bats (aged 1-2 years) than older animals (aged 4-8 years) so our results should be interpreted with caution. However, they are consistent with other studies showing that bats exhibit fewer signs of aging relative to other small mammals. In addition, we show significantly lower auditory thresholds among females compared to age-matched males, similar to sex differences reported in other mammals. Finally, we found increased thresholds in a single non-pigmented bat relative to age- and sex-matched conspecifics. While preliminary, this finding suggests that pigmentation may be important for inner ear function in bats, similar to results from other mammals.