ULTRASONIC EMISSIONS OF THE LESSER HORSESHOE BAT <i>RHINOLOPHUS HIPPOSIDEROS (BECH.)</i>

Abstract

The ultrasonic emissions of both adult and juvenile Lesser Horseshoe bats have been studied. Two features were observed:—The range of frequencies used by adult bats when congregated in a crowd of 60 or more does not exceed 3 Kc/s, even though their frequency of emission is of the order of 113 Kc/s. The baby bats can make sounds of echo‐location type within 3 days of birth; they open their mouths to do so when disturbed and the frequency of the sound at first is about 30 kc/s. Erratic variations in frequency take place during development.