These were flying reptiles that had evolved in the late Triassic but thrived during the cretaceous17. They had bird like features like the hollow bones but differed with birds in that instead of having feathered wings they had membranes. The membrane was extended from the torso to the limbs making their walking cumbersome3, 17. These were the first vertebrates to fly. They fed during flight feeding on fish as they practiced migratory habits like birds flying long distances in order to mate. The males had crests on their long beak like structures and which they exhibited brighter colors during the mating season (color display).Initially they had teeth but some later lost teeth17. An example is Ornithocheirus. It weighed up to 100 kg and had a wing span of about 12 meters with a body up to 3.5 meters3.