Ultrasonic Bat Chirps (AUDIO) University of California - Berkeley Your browser does not support the audio element. Caption A recording of the ultrasonic calls of western pipistrelle or canyon bats at Del Valle Regional Park in Livermore, Calif., slowed down to one-eighth normal speed to be audible to humans. Credit Qin Zhou, UC Berkeley Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.