Hearing Sensitivity in Bats

Abstract

Absolute hearing thresholds for two bats were determined by an operant conditioning technique. Pure tones ranging from 2.5 to 100 kilocycles per second were perceived by a single Eptesicus fuscus . Its maximum sensitivity was on the order of 68 decibels below 1 dyne per square centimeter and occurred at 20 kc/sec. Maximum sensitivity for a single Myotis lucifugus was about 64 db below 1 dyne/cm 2 and occurred at 40 kc/sec. The Myotis clearly heard a tone of 120 kc/sec but gave no evidence of hearing below 10 kc/sec.