Giant pterosaurs were masters of the air from 108 million to 70 million years ago. The biggest ones weighed 500 pounds, had a wingspan of 34 feet, flew 40 miles an hour, and covered hundreds of miles a day. They were unable to launch themselves like modern birds, though, so how did these prehistoric giants get off the ground? Common sense suggests they must have run a long distance, built up speed, and then leaped into the air.
Wrong, says Michael Habib, a paleontologist at Chatham University in Pittsburgh. “My findings suggest there was no running involved.” According to his analysis, published in the European journal Zitteliana, pterosaurs folded their wings so they could act as arms and then used all four limbs to shove themselves aloft. “Pterosaur arms were much stronger than their legs,” he says. “Together the wings could withstand more than 2,000 pounds of force in launch position. They would crouch down on all fours, vault, and push off.” Once airborne, the giant creatures would snap their wings into flying position and eventually soar.
Habib used CAT scans to analyze bone strength in a number of species of living birds and compared them to measurements taken from 12 species of pterosaurs. He could find no evidence to support the idea that large pterosaurs got off the ground using only their hind legs to launch. In this regard they resembled vampire bats, which use a “quadrupedal launch” to accelerate quickly, Habib says. This kind of launch allows the bat to employ its strongest muscles (in forelimbs and chest) for takeoff.
