for National Geographic News
Giant pterosaurs, colossal winged reptiles that lived alongside the dinosaurs, have long been considered the heaviest animals ever to take to the skies.
But new research suggests that the notion of giant pterosaurs soaring over Earth simply doesn't fly.
(Related: "Giant Flyers Hunted Dinos on Foot?")
Based on the weights and body sizes of modern birds, a new study finds that animals heavier than 90 pounds (41 kilograms) with wingspans greater than 16.7 feet (5.1 meters) wouldn't be able to flap fast enough to stay aloft.
The conclusion casts serious doubt on the flying ability of large pterosaurs such as Quetzalcoatlus, thought to be one of the largest airborne animals of all time.
The late-Cretaceous creature may have weighed up to 551 pounds (250 kilograms) and had up to a 34.1-foot (10.4-meter) wingspan—nearly as wide as a schoolbus is long.
"I think that the giant pterosaurs could not stay aloft in an environment similar to the present," said study leader Katsufumi Sato, an associate professor at the University of Tokyo's Ocean Research Institute.
Even if they could stay up, the bulky beasts would have had trouble getting off the ground in the first place, Sato said.
"Takeoff is the hardest task. I suppose they could not take off using only muscular efforts."
Sato, who is also a National Geographic Society emerging explorer, journeyed to the southern Indian Ocean to study the world's largest bird, the wandering albatross, and four smaller bird species. (The National Geographic Society owns National Geographic News.)
All five species are considered to be soaring birds—flyers that use a strategy of gliding punctuated by sporadic flapping, as pterosaurs are generally thought to have flown.
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