The evolution of flight took longer than previously thought with the ancestors of modern birds “rubbish” at flying, if they flew at all, according to a Manchester scientist.
Archaeopteryx, the theropod dinosaur believed to be the earliest bird, was discovered 150 years ago but debates about how flight evolved still persist. The two theories are that flight evolved in running bipeds through a series of short jumps or that Archaeopteryx leapt from tree to tree using its wings as a balancing mechanism.
Dr Robert Nudds at The University of Manchester is carrying out a series of biomechanical investigations to shed light on the subject with his colleague Dr Gareth Dyke at University College Dublin.
For their latest paper Dr Nudds and Dr Dyke applied a novel biomechanical analysis to the flight feathers of the early birds Archaeopteryx and Confuciusornis to find out if they were strong enough to allow flight.
They found that the dinosaur feathers’ much thinner central stem (rachis) must have been solid or they would have broken under the lift forces generated during flight or by gusts of wind. This solid structure is very different to modern birds, whose rachises are broader, hollow straws. If the dinosaurs’ feathers had had hollow rachises, they would not have been able to fly at all.
“These are surprising results,” says Dr Nudds, whose findings are published in Science today (13th May 2010).
“I thought the feathers would be strong enough with a hollow rachis to fly but they weren’t. Even with a solid rachis, they were not very good. These dinosaurs were rubbish at flying.
“This pushes the origin of flapping flight to after Archaeopteryx and Confuciusornis. It must have come much later.”