THE first evidence of grass-eating dinosaurs has been discovered, transforming our picture of the prehistoric world.
In the past, scientists had thought grass evolved after the dinosaurs had died out.
But the discovery of grass in the fossilised dung of dinosaurs proves that not only was grass growing 65 million years ago but that dinosaurs were eating it.
Caroline Stromberg, a paleobotanist at the Swedish Museum of Natural History in Stockholm and co-author of the study, analysed the dung found in India.
She was "totally shocked" to find evidence of different grasses, including relatives of rice and bamboo, growing ten million years earlier than previously thought.
"There are a lot of plant-eating dinosaurs, but we did not used to think that grasses had evolved in the dinosaur age," she said. "There were ferns, conifers, palm-like trees and other flowering plants."
Scientists think grass was being eaten by sauropods, dinosaurs with long necks and tails and small heads, although it was a small part of their diet.
Dr Stromberg said the findings also shed light on how grasses have evolved.
"Grasses today cover a fourth of the world's land surface and feed a lot of the world's population. Data on grasses this early tells us that its evolution is more complicated than we thought."