Pteranodon is a genus of pterosaurs which included some of the largest known flying reptiles, with wingspans over 20 feet. It existed during the late Cretaceous geological period of North America in present day Kansas, Alabama, Nebraska, Wyoming, and South Dakota. More fossil specimens of Pteranodon have been found than any other pterosaur, with about 1,200 specimens known to science. It was a reptile, but not a dinosaur. Their fossils are known primarily from the Niobrara Formation of the central United States, and existed for more than four million years, during the late Coniacian to early Campanian stages of the Cretaceous period. Like other pterosaurs, they probably took off from a standing, quadrupedal position. Using their long forelimbs for leverage, they would have vaulted themselves into the air in a rapid leap. The upstroke of the wings would have occurred when the animal cleared the ground followed by a rapid down-stroke to generate additional lift and complete the launch into the air. It seems quite likely they were ocean-going fish-eaters.