Echolocation and hearing in the mouse‐tailed bat (Rhinopoma hardwickei) Free

Rhinopoma produces four‐harmonic, constant frequency orientation sounds. The 7‐ to 8‐ms‐long search and 2‐ to 4‐ms‐long approach signals rise to full amplitude in two to three waves of the fundamental (18 kHz), producing an onset transient. This click‐CF signal appears unique to Rhinopoma and may link the complex orientation sounds of the Microchiroptera with the sonar clicks of shrews. The N₄ audiogram shows sensitivity peaks corresponding to the harmonic peaks of the signal spectrum. Sensitivity is particularly great for the second harmonic, the strongest component of the signal. This sharp tuning around the second harmonic suggests that primary auditory neurons may have Q‐10 dB values as high as 20 to 50. The sharp roll‐off on the low frequency side of this sensitivity peak further suggests Rhinopoma may perform the Doppler‐compensation response.