It might have been the ugliest duckling ever, but scientists using Canada geese for a model have determined that pteranodons, ancient flying reptiles, probably floated on water but not so prettily as their modern avian counterparts.

Like modern birds, the pteranodon had hollow bones, which would have made them light and buoyant. There is also evidence that the flying reptiles foraged in watery environments. But it takes computational modeling to work out exactly how they might have managed to float on water without drowning.

“This isn't about swimming. This isn't about diving,” clarified David Hone of Queen Mary University of London, who coauthored a paper on the work with Donald Henderson of Canada's Royal Terrell Museum of Paleontology. It's just about how the pteranodons floated.

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First the researchers tested their flotation model by reproducing the depth and position of a floating Canada goose. Then they tried to make it work for a pteranodon, shifting different variables around just to make certain they covered most possible poses for the flying reptiles in the water. What they found was that the creatures probably didn't sit well on the water surface. In fact they barely could keep their mouths above the water.

“A good analogy is a human,” Hone explained. “If I just lie in a swimming pool I barely have my mouth above the water.” And any waves would make it extremely hard to breathe.

But that does not mean pteranodons were bad at foraging in water, any more than it means humans can't swim, Hone said.

“It isn't necessarily a problem,” Hone said, citing modern birds that spend much of their lives over the ocean but are rather poor at floating on the surface. “Pterosaurs are the Cretaceous albatross.”

Other researchers who have modeled behaviors of pteranodon agree that the posture in the water is not a problem.

“I'm glad they put it in the water, said Sankar Chatterjee of Texas Tech University. “I was really surprised by the way the wings are really like a sail.”

Hone and Henderson published their work in the Dec. 1 issue of the journal Palaeogeography, Palaeoclimatology, Palaeoecology. Their abstract can be found here.