Mighty Mouse (IMAGE) Max-Planck-Gesellschaft Caption One giant mouse weighs more than six 'mini-mice' of the same age. The biggest mice in the world evolved through targeted breeding over many generations. Scientists can use these animals to identify the genes responsible for body growth. Credit Lutz Bunger, University of Edinburgh 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.