Fossils of feathered dinosaurs are no longer as terribly rare as they once were, even if they still are exciting finds. However, so far all feathered dinosaurs have been the flesh-eating two-legged raptors theorized to be the ancestors of modern birds. Now paleontologists have found evidence that some large plant eating dinos also sported bristly feathers, changing the rules for predicting who likely had plumage.

Some Onithischians - the vast dinosaur group that consisted of strict vegetarians - have been discovered to have three kinds of feathers protruding from well-preserved skulls.

The dinosaurs in question, Kulindadromeus zabaikalicus, lived 160 million years ago and is theorized to have been a plant eating swamp dweller. The dino likely used its front limbs to comb up food while it trounced around muddy ground on bipedal legs.

Leading an analysis of six partial skulls of K. zabaikalicus, Pascal Godefroit of the Royal Belgian Institute of Natural Sciences in Brussels found evidence of short bristle-like feathers that likely ran from the creatures' heads and down the length of their backs.

"I think their function was primarily for insulation," Godfroit told NewScientist.

Insulation feathers are not uncommon among flightless dinosaurs, even if this is the first time clear evidence of them has been found in a member of the Onithischian half of the dinosaur family tree.

Two other feathers the team found were much more interesting. Lengthened filaments similar to the downy feathers seen on modern birds likely sheathed the tops of the dinosaur's limbs, and evidence of strange ribbon-like feathers were also found around leg bones.

"They consist of clusters of six or seven ribbon-shaped elements bundled together," said Godefroit. "There's nothing like it in modern birds."

According to the team's conclusions , the best explanation for these limb feathers they can think of is display.

A study detailing these findings was published in the journal Science for July 25.