Northern Water Snake (image) American Museum of Natural History Share Print E-Mail Caption This is a northern water snake (Nerodia sipedon) with crusty and thickened scales overlaying raised blisters as a result of a fungal skin infection. Credit © USGS National Wildlife Health Center/D.E. Green Usage Restrictions Can be used with appropriate 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.