Inner ears of mammal ancestors. (IMAGE) University of the Witwatersrand Caption Size differences between inner ears (in grey) of warm-blooded (on the left) and cold-blooded (on the right) mammal ancestors. Inner ears are compared for animals of similar body sizes. Credit Romain David and Ricardo Araújo Usage Restrictions No restrictions. License Public Domain 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.