Dinosaurs were flapping wings even before they could fly

Even before the dinosaurs evolved the ability to fly, they may have begun to flap their wings as a passive effect of running along the ground, according to a study.

The findings, published in the journal PLOS Computational Biology, provide new insights into the origin of avian flight, which has been a point of debate since the 1861 discovery of Archaeopteryx.

While a gliding type of flight appears to have matured earlier in evolutionary history, increasing evidence suggests that active flapping flight may have arisen without an intermediate gliding phase, researchers said.

"Our work shows that the motion of flapping feathered wings was developed passively and naturally as the dinosaur ran on the ground," said Jing-Shan Zhao from Tsinghua University in China.

"Although this flapping motion could not lift the dinosaur into the air at that time, the motion of flapping wings may have developed earlier than gliding," Zhao said.

To examine this key point in evolutionary history, they studied Caudipteryx, the most primitive, non-flying dinosaur known to have had feathered "proto-wings."