Heating of Haired and Hairless Mice in High Intensity Sound Fields from 6 to 22 kc

Experiments have been conducted to provide a comparison of sound absorption by haired and hairless mice in high intensity air-borne sound fields. At 18–20 kc, threshold intensities for heating of the mice are 144±2 db for haired animals and 155±2 db for hairless animals. From 6–22 kc, effectiveness of the sound in heating the mice increased with frequency. Absorption coefficients computed from the data are higher at higher frequencies for both types of animals. Death time is dependent upon intensity and frequency of the sound, external covering of the animals, and portion of the animal exposed to the most intense part of the sound field. At frequencies of 18 and 22 kc, localized burns were found on hairless animals, and these were studied. The configuration of the sound field and its relation to the results is discussed. Measurements of the field made with and without a hairless mouse showed increased distortion at higher frequencies of the sound field by the body of the mouse.