Tree-Dwelling Animals Were The First To Fly, New Research Suggests

A six-legged, 25 g robot has been fitted with flapping wings in order to gain an insight into the evolution of early birds and insects.

Published on 18 October, in IOP Publishing’s journal Bioinspiration & Biomimetics, the study showed that although flapping wings significantly increased the speed of running robots, the origin of wings may lie in animals that dwelled in trees rather than on the ground.

The flapping wings increased the speed of the running robot by 90%, going from 0.68 m/s to 1.29 m/s, and also enabled it to climb steeper gradients, increasing from a 5.6° ascent to a 16.9° ascent, which would be important in the development of a hybrid running and flying robot that could have several civilian and military applications.

The researchers, from the University of California, Berkley and the Smithsonian Tropical Research Institute, proposed that testing the wings on robots could provide an insight into how they evolved in early birds.

Fossils of animals closely related to dinosaurs, dating back further than when birds actually emerged, show that feathers were present on all four limbs, suggesting that the original function of wings was to help animals glide when dropping from a height, much like a paper aeroplane.

An alternative theory is that the first wings may have appeared in land-based animals, functioning as a mechanism to increase running speeds and then leading to take-offs and flying thereafter. The aim of this research was to gauge how much of an advantage flapping wings give a running animal.

“By using our robot we can directly determine the performance effects of flapping wings on a running platform as well as gaining a much greater mechanical insight into how the wings are actually working on the robot. We are thus able to look at the performance of the wings directly rather than attempting to build theoretical aerodynamic models based on fossil morphologies that may be overly sensitive to various assumptions”, said Kevin Peterson, lead author of the study.

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