Pterodactyl Take-Offs Kept These Giants in Check

Pterodactyls were truly giants of the sky during their time, but their tricky take-offs from the ground kept these flying dinosaurs in check, preventing them from becoming even bigger behemoths, according to a new study.

Based on cutting-edge engineering techniques with paleontology, researchers determined that the species' four legged take-off maneuver would prevent any pterodactyl with a wingspan of 12 meters (39 feet) or more from getting off the ground.

The largest species of pterosaurs - commonly referred to as pterodactyls - had wingspans reaching up to 10 meters (33 feet) and may have weighed as much as a quarter of a ton. Even at just one third this size they would have dwarfed the largest known bird. And given their massive wings it's a wonder these colossal creatures managed to take flight at all.

According to the new study, take-off capacity may have determined body size limits in extinct flying reptiles such as pterodactyls.

"Getting into the air ultimately limited pterosaur size. 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," Colin Palmer, a mechanical engineer and doctoral student at the UK's Bristol University, said in a press release.

To better understand the mechanics of pterodactyl flight, Palmer teamed up with Mike Habib, an anatomist and paleontologist at University of Southern California. Together they used 3D imaging of fossils to create a computer model of a pterosaur with a 6-, 9- and 12-meter wingspan. These simulations were used to estimate the wing strength, flexibility, flying speed and power required for flight in massive pterosaurs.

While even the largest of these giants could easily stay aloft by utilizing air currents effectively, as well as slow down using the flexible membrane of their wings, taking off was a different story.

These prehistoric birds used what's called a "quadrupedal launch" technique to get off the ground, meaning they likely used both their arms and legs to liftoff into the air - unlike modern birds. However, once wingspans approached 12 meters, the push-off force required to get the model off the ground was too great.

The research will be presented at the upcoming Society of Vertebrate Paleontology meeting in Berlin.