Appliance of Science: Do bats use sonar to communicate?

Nine-year-old Emma would like to know… “DO BATS USE SONAR TO COMMUNICATE WITH EACH OTHER OR JUST TO LOCATE OBSTACLES AND FOOD?”

Before answering Emma’s question, it would perhaps be helpful to define some words and terms: sound travels in waves and is often referred to in terms of frequency. Frequency is really a measure of how often something vibrates. The frequency of sound is expressed in hertz (Hz).

Humans can usually hear sounds that have a frequency between 20 Hz and 20 kHz; however, many animals can make, and hear, sounds outside of this range. Some, like bats, make sounds above 20 kHz and this sound range is referred to as ultrasound (or ultrasonic sound).