Evolution

08
Jul

Extinct Flying Bird Was So Big It Shouldn’t Have Been Able to Fly

What had saw-like teeth, a wingspan three-times wider than LeBron James’s, and lived in South Carolina? The newly-named world’s largest flying bird, Pelagornis sandersi. With a wingspan of up to 24 feet, the monstrosity was so large that it defies common scientific wisdom—something that big, many scientists think, shouldn’t be able to fly.

P. sandersi lived and fished off the coast of South Carolina some 3 million years ago. The fossils—a skull and most of the right wing and leg—were first dug up in 1983 during the expansion of the Charleston International Airport, but it wasn’t until recently that paleontologist Daniel Ksepka realized that they represented a new species. It’s a member of the pelagornithid family, which was pretty common back then. But none its relatives are known to have grown to such an enormous scale.

Pelagornis sandersi
What scientists think Pelagornis sandersi looked like.

Most birds of that size are earthbound, so P. sandersi is something of a puzzle. Jane Hu, reporting for Slate:

Based on the structure of its bones, scientists are fairly certain that P. sandersi did fly. This raises one big mystery: How did something so large stay in the air? Bigger animals require more power to keep their bodies in flight. “It’s a scaling problem,” says Ksepka: Theoretically, extremely large birds cannot fly, because the amount of power they need to fly surpasses the power of their muscles. Some researchers calculate that this upper limit is around 17 feet, so by these estimates, a flying Pelagornis sandersi should be impossible. However, these calculations are based on the energy required for birds to stay in flight by flapping their wings; in new calculations, Ksepka proposes that large flying birds could have used other strategies. “They could harvest energy from the environment, like taking advantage of wind gusts,” he says. Like modern-day albatrosses, Pelagornis sandersi could have used their long wings to catch ocean winds and glide across the sky, rather than powering their flight with energy-intensive flapping.

Still, P. sandersi positively dwarfs albatrosses, which have wingspans up to 12 feet. The new find also outdoes another previous record holder, which happens to be from the same family—P. chilensis, which lived 5 to 10 million years ago and had a wingspan of 17 feet.