Dino model shows the glide path to flight

Microraptor was a two-footed dinosaur - theropod - and the first to have feathers on its arms, legs and tail (Source: Jason Brougham/University of Texas, Austin)

ABC/AFP

Scientists using a wind tunnel and a full-scale model have shed light on how feathery dinosaurs adapted to the skies, a new study reports.

A widening consensus among palaeontologists is that birds evolved from small, feathery dinos. But the question is how?

Researchers at the University of Southampton created an anatomically correct model of a five-winged dinosaur deemed to be a precursor of birds.

"Normally people build models without the feathers, but we've tried to include the feathers because they bend with the wind and so we've got a combination of effects going on there," says study co-author Colin Palmer.

Microraptor was a two-footed dinosaur - theropod - and the first to have feathers on its arms, legs and tail, providing it potentially with five surfaces with which to gain "lift" against the air.

"It was a small animal that was discovered 15 years ago in the north east of China, and supposed to have been one of the first to have flown. So understanding how it flew is really important to know how flight began 150 million years ago," says Jacques Van der Kindere who was also involved in the study.

Experiments in a wind tunnel, supported by flight simulations, showed that even though these wings were rudimentary compared to those of modern birds, it could still carry out slow glides from low heights.

"Using a wind tunnel allows us to measure lift - the amount of force it could produce vertically to keep it in the air - the drag - the resistance to motion, and those two together gives us an idea of the speed that the animal could fly at. It also gives us the ability to look at the stability," says Palmer.
From a height of about 30 metres, it could glide between 70 and 100 metres - a useful means of grabbing a prey or fleeing a predator.

Judged by this, microraptor probably climbed a bit, foraged for food on the ground and glided only on occasion, say the authors.

"Microraptor did not require a sophisticated 'modern' wing morphology to undertake effective glides," write the authors of the paper published in the journal Nature Communications.

"Symmetric feathers first evolved in dinosaurs for non-aerodynamic functions, later being adapted to form lifting surfaces."

A leading hypothesis in the origin of birds is that, after learning to glide, feathered dinosaurs underwent evolutionary pressures that led to a more sophisticated wing, able to flap efficiently and adapt its shape to winds.