It’s possible that all dinosaurs had feathers.

Scientists previously believed that only avian dinosaurs – that is, the direct ancestors of our modern birds – sported feathers along with their scales. But the discovery of fossilized feathers on a newly identified dinosaur far removed from the bird lineage means that feathers likely were more widespread in the dinosaur world.

The discovery, published Thursday in Science, could change scientists’ understanding of how and why feathers evolved.

Several partial skeletons of the new dinosaur, called Kulindadromeus zabaikalicus, were discovered in a recent geological survey of the Kulinda Valley in Siberia. A plant-eating dinosaur that lived during the Jurassic period and only reached about five feet long, it didn’t use its feathers for flying.

“It’s impossible that they flew,” said lead study author Pascal Godefroit, director of earth and life sciences at the Royal Belgian Institute of Natural Sciences. “They were bipedal and had long legs with very, very short arms.”

Their feathers varied from quite primitive – structures like bristles or hair – to downy feathers much like those seen on modern birds, Godefroit and his colleagues reported. The bristles most likely served as insulation, indicating that it was warm-blooded, Godefroit said.

The more advanced feathers, which were found around the legs of the dinosaur, were probably decorative. “To us that implies that they had some kind of social life,” he said, and that they used the more elaborate plumage to attract mates.

This adds further weight to previous theories about feathers – that they originally evolved for something other than flight. “Flight is the latest stage in feather evolution,” Godefroit said. Even after bird ancestors developed truly bird-like feathers, he said, they were gliding instead of flying.

University of Calgary assistant professor of geoscience Darla Zelenitsky, who wasn’t involved in the study, agrees. “This discovery suggests that feathers became a useful tool early on in dinosaur evolution, whether it was for camouflage, display or insulation,” she said.