Photo 3 (IMAGE) National University of Singapore Caption The compact sonar comprises three sound transmitters which emit sharp, impulsive click sounds similar to a dolphin’s echolocation. Credit National University of Singapore Usage Restrictions NA License Original 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.