Thirteen-Lined Ground Squirrel (IMAGE) University of California - Santa Cruz Caption A thirteen-lined ground squirrel (Ictidomys tridecemlineatus) at the Pawnee National Grassland in northeastern Colorado. Species in the squirrel family are likely to have two or three alternative mating strategies (polygynous, monogamous, and sneaker). Credit Alexis Chaine Usage Restrictions For use only with news coverage of this research 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.