Scientists have uncovered the remains of a group of dinosaurs that may have been choosing to become vegetarians.
They've found a "mass graveyard" of dino bodies in the US state of Utah that had feathers like birds and seemed to be giving up meat when they died.
At some point during the time of the dinosaurs two groups of them swapped eating meat for munching on plants.
The scientists hope the fossils will tell them more about how the dinosaurs changed from a meat diet to plant one.
The site contains hundreds and perhaps thousands of fossils of the dinosaurs, which look to be in between meat-eating dinos and plant-eating ones.
Meat eaters tended to be very lean and fast because they had to catch their food, while the vegetarians were slower and much bigger.
They needed bigger bellies to process the plants into food, which meant they then needed larger legs too, to carry them around.
These fossils of the dinosaurs, named Falcarius utahensis, have larger stomachs and the small teeth of plant-eaters, but would still have been quick-moving and kept the sharp claws of meat-eaters.