Paleontologists have long inferred the diets of extinct dinosaurs based on the shape of the teeth. Most dinosaurs with sharp, bladed and serrated teeth, like steak knives, belong to the group of dinosaurs called theropods, such as Tyrannosaurus, Allosaurus, and Velociraptor. These animals most likely used their teeth to slash prey and slice meat. Other dinosaurs possessing sets of teeth that wore down into flat grinding surfaces as the animal chewed, such as Triceratops and duckbills, most likely used their teeth to grind or shred leaves, seeds, and other vegetation.