Synapsid Recreation -- at Night (image) Field Museum Share Print E-Mail Caption The new study reveals that Dimetrodon's would have been one of many synapsids who were active at night. Credit Illustration by Marlene Hill Donnelly Usage Restrictions Must use 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.