Pterosaur
In the Lower Cretaceous there were many pterodactyloids, mostly quite small. Gradually, larger versions evolved, and by the Upper Cretaceous most pterosaurs had huge wing-spans and clearly covered huge distances soaring on upcurrents in a warm environment. Pteranodon, with a wing-span of over 20 feet (7m), and Quetzalcoatlus, with a wingspan of 40 feet (12m) are famous examples. The many dozens of partial skeletons of Pteranodon were found in areas where, in the Cretaceous of North America, there was a gigantic inland sea, the Western Interior Seaway. That makes it more or less certain that Pteranodon was mainly a fish-eating pterosaur. And, other sites in England and Argentina were also, at the time, shallow, warm inland seas. The general conclusion is that most pterosaurs were fish-eaters.