Pterosaurs launched themselves into the air by pole-vaulting with their arms, new research suggests.
There's been much debate in recent years about whether these giant creatures could actually fly, given the obvious difficulties in getting off the ground.
But Dr Mark Witton from the University of Portsmouth and Dr Michael Habib from Chatham University say that pterosaurs used a different technique to the run-and-jump method of birds.
They believe that pterosaurs took off by using all four of their limbs and effectively 'pole-vaulting' over their wings using their leg muscles, while pushing from the ground with their powerful arms.
Once airborne, they could fly huge distances and even cross continents.
"Most birds take off either by running to pick up speed and jumping into the air before flapping wildly, or if they’re small enough, they may simply launch themselves into the air from a standstill," says Witton.
"Previous theories suggested that giant pterosaurs were too big and heavy to perform either of these manoeuvres and therefore they would have remained on the ground."
However, because pterosaurs have a distinctly different skeletal structure, wing proportion and muscle mass to birds, there's no reason to assume they moved in the same way, says the team.
"They would have achieved flight in a completely different way to birds and would have had a lower angle of take off and initial flight trajectory. The anatomy of these creatures is unique," says Witton.
Drs Witton and Habib suggest that, with up to 50 kgs of forelimb muscle, the creatures could easily have launched themselves into the air despite their massive size and weight.
"Instead of taking off with their legs alone, like birds, pterosaurs probably took off using all four of their limbs," says Habib.
"By using their arms as the main engines for launching instead of their legs, they use the flight muscles – the strongest in their bodies – to takeoff and that gives them potential to launch much greater weight into the air."
The researchers examined every available anatomical aspect of pterosaurs, which died out 65 million years ago. Using fossilised remains they estimated size and weight and calculated bone strength and mechanics and potential 'flap gliding' performance.
They concluded that not only could pterosaurs fly, they could do so extremely well and could have traveled huge distances.