Anolis Cristatellus (IMAGE) Washington University in St. Louis Caption Anolis cristatellus lizards are abundant in urban areas in Puerto Rico. New research from Washington University shows that the city lizards have rapidly and repeatedly evolved greater heat tolerance that enables them to thrive in urban heat islands. Credit Kristin Winchell / Washington University Usage Restrictions For editorial purposes 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.