Cosmic Impact, Mastodons (IMAGE) Dartmouth College Caption An artist's rendition of mastodons, camels and a ground sloth before the environmental changes of the Younger Dryas led to their extinction. Credit Barry Roal Carlsen, University of Wisconsin Usage Restrictions The artist must be credited. 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.