Pecking Order (IMAGE) University of Cincinnati Caption The study of pecking order began in chickens 100 years ago. Today, researchers are studying dominance hierarchies in primates, whales, insects and countless other animals. Credit Michael Miller Usage Restrictions None License Original 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.