Frog Calling (IMAGE) University of Arizona Caption Frogs, like mammals, originated as predominantly nocturnal animals, but maintained the ability to communicate acoustically after switching to being active during the day. Credit Peter Trimming/Creative Commons Usage Restrictions This visual may only be used in conjunction with reporting or posting this news release. Credit must be given as indicated. 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.