Baby Sonoran Desert Tortoise (IMAGE) Aarhus University Caption Reptiles like this baby Sonoran Desert tortoise in Arizona are ectotherms but not necessarily cold-blooded; its blood temperature depends on the ambient temperature. And THAT is getting dangerously hotter. Credit Cortesy of U.S. Fish & Wildlife Service Southwest Region Usage Restrictions No restrictions. License Public Domain 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.