In Conrad's opinion, the leathery wings of a pterosaur are the best possible flight mechanism for a giant lizard. "Quetzalcoatlus had a 30-foot wingspan," he says. "That would do the trick." Big, strong wings are necessary to compensate for the weight of a dragon's skin, which, of course, would need to withstand bow-and-arrow attacks. "Let's throw a little alligator in there for armor," Conrad says. An alligator's skin, he explains, is made partly of bony plates. When European settlers first encountered the reptiles, the skin proved to be tough enough to turn away a musket ball, plenty strong for a dragon.