Feathers could have advanced on dinosaurs to frighten and flush out prey earlier than they have been used for flight, say researchers who constructed a winged robotic and used it to scare grasshoppers.

Pennaceous feathers, that are the stiff, non-downy feathers which have a central quill, are seen in fossils of some dinosaurs reminiscent of Caudipteryx, which lived about 124 million years in the past. These dinosaurs had wings however they weren’t robust sufficient for flight, so it’s unclear how they have been used.

Jinseok Park from Seoul Nationwide College, South Korea, and his colleagues hypothesised that they have been used to startle prey into fleeing from hiding locations, in order that they could possibly be caught extra simply. This “flush-pursuit” looking technique is utilized by trendy birds together with the larger roadrunner (Geococcyx californianus) and the northern mockingbird (Mimus polyglottos).

To check this concept, Park and his colleagues constructed a life-size robotic mannequin of Caudipteryx, nicknamed Robopteryx. The robotic approached grasshoppers, which have been a possible prey of Caudipteryx, earlier than flapping its wings. With out feathers, slightly below half of examined grasshoppers fled, however when the researchers hooked up feathers to the wings, this elevated to over 90 per cent.

The group additionally recorded the neural responses of grasshoppers whereas they have been proven an animation of Caudipteryx. They noticed stronger exercise in neurons concerned in escaping reactions when the feathers have been current within the animation than with out.

Park says the examine demonstrates that flush-pursuit looking was a doubtlessly essential issue within the evolution of pennaceous feathers on the arms and tails of dinosaurs.

“This might, in flip, result in the evolution of bigger and stiffer feathers, contributing to extra profitable pursuits and distinguished visible flush-displays,” he says.

Predators with pennaceous feathers would have been in a position to flush out prey from additional away, enabling them to see the trajectory of escaping prey, says Park. That will permit them to catch prey within the air comparatively simply, he says. Even when the prey landed in vegetation, the predator might see the place it landed and observe them.

“We imagine that pennaceous feathers advanced first for flush pursuing and have been used later for flight,” Park says.

However Steven Salisbury from the College of Queensland, Australia, says this rationalization might be too easy. “It appears to me to be impossible {that a} construction as complicated as a pennaceous feather would evolve for such a particular behavioural function,” says Salisbury. “I’m certain there are many methods to scare grasshoppers apart from to flap some feathers at it.”

There may be most likely no single motive why feathers advanced, he says. “You may have feathers to scare grasshoppers and you’ll have them to insulate and incubate eggs; they’re good for show; the stabilisation of physique place when operating, and naturally for gliding and powered flight. Feathers assist for all kinds of issues.”