Devil Ray (IMAGE) Duke University Caption Giant devil rays can grow up to 17 feet long, but scientists still have spotty knowledge about their population size, movements and birthing zones. Credit Patrik Neckman, via Wikimedia Commons Usage Restrictions None License Licensed 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.