Brain vs. Brawn (IMAGE) University of Pennsylvania School of Medicine Caption Florida carpenter ants, minor caste (left) and major caste, are shown. Credit The lab of Shelley Berger, PhD, Perelman School of Medicine, University of Pennsylvania Usage Restrictions None 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.