### Instruction: Did dinosaurs have lips?
### Response: Recent research suggests that the popular perception that dinosaurs had exposed teeth may be incorrect, and the current hypothesis is that the Tyrannosaurus rex did indeed have lips. A 2023 study by Dr Mark Witton of the University of Portsmouth said popular depictions of dinosaurs in movies like Jurassic Park are out of date. The study examined a large tooth that had spent over 500 days in the mouth of a Tyrannosaurus rex with no evidence of substantial wear, which is consistent with all findings of teeth found in the theropod family of dinosaurs. When contrasted with alligators and crocodiles, who have no lips and have more easily damaged teeth the theory says the evidence points to theropods, including Tyrannosaurus rex did indeed have lips. There would have been expected to be wear on the thin enamel on the teeth far more consistent with modern animals like crocodiles if dinosaurs had no lips.