But now we know that pterosaurs simply flew differently than birds do. Instead of running and flapping their wings, the pterosaurs used all four limbs to launch themselves up into the air.
In a study presented today at the Society of Vertebrate Paleontology meeting in Berlin, Colin Palmer (a mechanical engineer and doctoral student at Bristol University) and Mike Habib (a paleontologist at the University of Southern California) combined their areas of expertise to put this unique method of flight to the test.
The researchers worked with a pterosaur model created using 3-D scans of available fossils, scaling the creature to different sizes. They found that the creature could take off using the proposed four-limbed method, and that its flexible membrane-covered wings allowed it to modulate speed, slowing down enough to land safely.
But while a model with a wingspan of nearly 40 feet (larger than any known real-life pterosaur) could still stay airborne, it couldn't actually get itself off the ground. That four-limbed takeoff may have done some serious heavy lifting, but it had limits.
"Getting into the air ultimately limited pterosaur size," Palmer said in a statement. "Even with their unique four-legged launch technique, the iron laws of physics eventually caught up with these all-time giants of the cretaceous skies."