Behavioural audiograms from the bat,Rhinolophus ferrumequinum

SummaryA conditioned heart rate and muscular activity response was used to measure behavioural audiograms inRhinolophus ferrumequinum. The audiograms are very similar to the evoked potential “on” response threshold curves. They show a low frequency roll off of 30 dB per octave below 15 kHz and three areas of low threshold with SPLs of about 0 dB separated by two insensitivity peaks with SPLs of 25–30 dB. The sharply tuned threshold minima above 80 kHz (Q-values between 45–85) are followed by a high frequency roll off of 160–170 dB/octave.