The feeding style adopted by Quetzalcoatlus is controversial. Originally it was theorised that Quetzalcoatlus fed on fish, scooping them from the sea as it flew overhead. It has also been suggested that the pterosaur was a scavenger, because some remains had been found in an area devoid of lakes or rivers, and was far inland. But the shape of its jaw suggested to others that it could have fed by skimming over the sea and collecting fish in its mouth. This skimming technique was later disproved because the energy costs for the shape of the pterosaur would be too high, as well as the fact that the remains were found in an inland area rather than a coastal environment. Another theory suggests that Quetzalcoatlus hunted by terrestrial stalking, hunting small vertebrates on land or in streams. The modern analogue for this behaviour is in storks. Quetzalcoatlus would have walked on its hind legs and folded wings.
One important point to remember is that pterosaurs were not dinosaurs! Dinosaurs are terrestrial animals only! This includes plesiosaurs and similar marine creatures contemporaneous with dinosaurs, which were actually marine reptiles.
