A cold-blooded animal is an animal that is unable to regulate its own body temperature and relies on external sources to maintain its temperature. Reptiles are a type of cold-blooded animal, as they rely on the environment to keep their body temperature at a suitable level. Reptiles are a class of animals that includes snakes, lizards, turtles, crocodiles, and tuataras. They have scaly skin, lay eggs, and are ectothermic, meaning they rely on external sources to regulate their body temperature.