Morphology Changes with Different Prey (IMAGE) Case Western Reserve University Caption Bigmouth sleepers that feed on other fish have more elongate bodies, with their greatest body depth shifted toward their tail to provide quicker acceleration. They have larger mouths that open wide to more effectively suck in evading fish prey. Sleepers living without other fish eat invertebrates. They have deeper heads with a smaller mouth that allows them to produce a narrower but much more powerful suction to capture small prey. Credit Modified from (Case Western Reserve University) Usage Restrictions Please give proper credit. 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.