Siberian Hamsters (IMAGE) University of Chicago Medical Center Caption The Siberian hamster on the left is in the summer breeding condition; the hamster on the right is in the winter non-breeding condition. Credit Tyler Stevenson 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.