Lizzard (image) Technical University of Munich (TUM) Share Print E-Mail Caption An air-filled cavity connects the eardrums of the two ears of this lizzard. In this "tunnel through the head" external and internal sound waves superimpose to produce signals enabling the animal to localize the direction of the sound source. Credit Prof. Dr. Frieder Mugele, University of Twente Usage Restrictions None Share Print E-Mail 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.