The Tyrannosaurus rex may not have had the iconic sharp-toothed grin it’s often depicted with, according to new research published in the journal Science. The study suggests that the dinosaur’s teeth were covered by scaly lips and did not protrude from its closed mouth, and that scientists have long been mistaken in their depictions of dinosaurs’ mouths. The researchers found clues in the pattern of tooth wear and tear, and compared the skulls of dinosaurs and modern reptiles. They concluded that while the lips texture would likely be thin and scaly, adding lips would make the monsters look more realistic and less like traditional monsters.