The debate over what Pterosaurs and their relatives are covered in has been a very, very long one. Did they have hair? Is it feathers? Is it something completely different? Is it the same integument dinosaurs have? Steven goes over the history of the research and debate of just what is making up their fuzz, how we know, and what it means. See how x-ray, infrared, UV, etc. can be use to study fossils and help draw a better picture of what researchers are looking at. Or what crushing bird feathers can tell us. And just what Pterosaurs needed all that fuzz for.