Big brown bats (Eptesicus fuscus) emit intense biosonar calls and process returning echoes to forage and guide flight. Sound pressure levels of emissions can exceed 110-120 dB SPL, amplitudes known to produce temporary threshold shifts in other vertebrates. We conducted behavioral experiments to test the limits of bats’ ability to navigate after intense noise exposures. Bats were trained to fly through a dense array of chains that produce a pattern of echoes mimicking those they would receive when flying along vegetation. We quantified flight accuracy (10 flights) and changes in the number and temporal patterning of emissions before and after exposure to intense broadband noise (1 hr, 116 dB SPL). Four bats tested 20 min post-exposure maintained flight accuracy and did not alter the temporal patterning of emissions from that observed pre-exposure. In contrast, two of three bats tested 2 min post-exposure initially would not perform the task or made errors in navigation. Temporal patterning of emissions du...
Find this article in full text from Scitation.