Reptiles are lung-breathing, scale-covered animals that are ectothermic, or “cold-blooded“. Being “cold-blooded” means that reptiles cannot regulate their own body heat so their warmth has to come from the environment around them. All reptiles are vertebrates, which means they have a backbone. Some reptiles lays eggs and some give birth to live young like mammals do. There are over 9,300 species of reptiles.