Protoceratops Skull (image) University of California - Davis Share Print E-Mail Caption This plant-eating dinosaur, Protoceratops andrewsi, was active day and night, like many other herbivorous dinosaurs. Credit Lars Schmitz, UC Davis. Usage Restrictions May be used with 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.