How Cooperative Thrives or Fails (image) University of Pennsylvania Share Print E-Mail Caption Despite their reputation, spotted hyenas are often cooperative animals, dwelling in large groups and assisting one another during hunts. Penn biologist Erol Akçay modeled a theoretical social group to show how cooperation can arise or collapse. Credit Amiyaal Ilany Usage Restrictions In context of reporting 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.