Published on November 12th, 2012 | by James Ayre0
Giant Pterosaurs Relied On Cliffs And Downward Sloping Ramps For Flight Takeoff, Research Says
The flight mechanics of the largest flying animal known to have ever existed, the giant Quetzalcoatlus, have long been a mystery. How could an animal that likely weighed around 155 pounds and with over a 34-foot wingspan fly effectively? Especially when it had such flimsy hollow bones?
The animal was so large that if it was any larger it would have likely been forced to walk, according to researchers. The five-foot-long skull that it possessed would have been on top of a body as tall as a giraffe, but much, much wider.
But now, using a new computer simulation, researchers have potentially revealed some of the qualities and features that allowed the giant pterosaur to fly.
“This animal probably flew like an albatross or a frigate bird in that it could soar and glide very well,” Sankar Chatterjee, Horn Professor of Geosciences and curator of paleontology at the Museum of Texas Tech University, said. “It spent most of its time in the air. But when it comes to takeoff and landing, they’re so awkward that they had to run. If it were taking off from a cliff, then it was OK. But if Quetzalcoatlus were on the ground, it probably had to find a sloping area like a river bank, and then run quickly on four feet, then two to pick up enough power to get into the air. It needed an area to taxi.”
There has been a lot of disagreement on what this animal actually looked like. There has been some talk lately by other researchers that Quetzalcoatlus could have gotten up towards 550 pounds by utilizing its forelimbs as a ‘catapult’ in a similar way to what the vampire bat does.
According to the computer models used in the new research though, “what is possible for a tiny, lightweight, 1-ounce bat appeared impossible for an animal 10,000 times heavier.”
The models say that flight performance seems degrades systematically with increased body size because the comparative power decreases. “Above a particular size, the available power is insufficient and flapping flight is not possible. The animal would not be able to maintain height when flying at its maximum power speed and exert full power.”
“Its enormous wings must have been difficult to manage,” Chatterjee said. “Each wing had at least a 16-foot span, so during its full downstroke it would smash its wing resulting in crash landing. A standing takeoff of flying of such a heavy animal violates the laws of physics.”
“Like today’s condors and other large birds, Quetzalcoatlus probably relied on updraft to remain in the air, Chatterjee said. It was a superb glider with a gliding angle close to two degrees and a cruising speed of 36 miles per hour. Their bones were entirely hollow, filled with air, lightweight and strong. This is how such a large animal could weigh so little and still grow to its enormous size.”
“The animal had high-aspect-ratio wings like those of modern seabirds, meaning the wings were long, narrow, flat and pointed. It soared in open airspace by exploiting thermals or wind gradient above the ocean surface. Trading for size, the wings were structurally weak for vigorous flapping, causing the pterosaur difficulty during ground takeoff.”
“Sooner or later the animal would come to the ground, especially during foraging and nesting,” Chatterjee said. “Like albatrosses and the Great Kori bustards, which weigh 20 to 40 pounds, ground takeoff was agonizing and embarrassing for Quetzalcoatlus. With a slight headwind and as little as a 10-degree downhill slope, an adult would be able to take off in a bipedal running start to pick up flying speed, just like a hang glider pilot. Once it got off the ground, the giant pterodactyl entered into thermal and soared like majestic masters of the air.”
Source: Texas Tech University
Image Credits: Texas Tech University