A large Totonacan Rattlesnake (IMAGE) Proceedings of the National Academy of Sciences Caption A large Totonacan Rattlesnake (Crotalus totonacus) uses its tongue to sample the air in the mountains of Tamaulipas, Mexico. Credit Image credit: Jason M. Jones 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.