Original sentence: Being cold blooded their energy requirement is about a 5th to a 10th of that of a mammal of the same size.Reptiles, or members of the class Reptilia, are air-breathing, cold-blooded amniotes that have skin covered in scales or scutes as opposed to hair or feathers
Edited sentence: Being poikilotherms (with varying body temperature regulated by their environment) their energy requirement is about a 5th to a 10th of that of a mammal of the same size.Reptiles, or members of the class Reptilia, are air-breathing, "cold-blooded" (poikilothermic]]) amniotes that have skin covered in scales or scutes as opposed to hair or feathers