Ravens (image) University of Vienna Share Print E-Mail Caption If a conspecific "cheated", the cooperation was denied subsequently. Credit Copyright: Jorg Massen, Universität Wien Usage Restrictions The image may only be used with appropriate caption or credit. 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.