Speaker 1: Welcome to Brainstuff, a production of iHeartRadio, Hey Brainstuff. Laurin
Speaker 1: Vogelbaum here. If you're like me, you've never really thought
Speaker 1: about whether or not Tyrannosaurus rex might have been a
Speaker 1: good kisser. Depictions of the so named tyrant lizard king
Speaker 1: a typically fixture a veritable phalanx of teeth protruding from
Speaker 1: its mouth even when its mouth is closed. It's an
Speaker 1: image made famous by the Jurassic Park movies. Think of
Speaker 1: that creepy crocodilian grin as it's hunting Doctor Grant, or
Speaker 1: you if you've been on the theme park ride. But
Speaker 1: that image might not be accurate after all. A study
Speaker 1: published in March of twenty twenty three in the journal
Speaker 1: Science postulates that the t rex and its fellow therapod
Speaker 1: dinosaurs actually did have lips that covered their teeth, more
Speaker 1: like modern lizards than crocodilians. A paleo Artists have often
Speaker 1: depicted therapod dinosaur mouths as similar to those of alligators
Speaker 1: and crocodiles, with enormous teeth protruding yet by comparing the
Speaker 1: ratio of tooth size to skull length with that of
Speaker 1: lizards like the komodo dragon. The researchers behind the study
Speaker 1: concluded that t rex teeth weren't necessarily too big to
Speaker 1: be covered by dino lips. The authors bolstered their claim
Speaker 1: by comparing the teeth of a close relative to the
Speaker 1: t rex, the Displetosaurus, with those of an American alligator.
Speaker 1: While the enamel on the outer side of an alligator's
Speaker 1: teeth tends to wear down pretty quickly due to exposure
Speaker 1: to the elements, the enamel of the dinosaur's tooth evidenced
Speaker 1: no such pattern. This suggests the possibility that its teeth
Speaker 1: were protected behind lips. The last piece of evidence the
Speaker 1: study relied on is the similarity between certain features of
Speaker 1: therapod dinosaur skulls and the skulls of lipped lizards like iguanas.
Speaker 1: A lipless crocodiles and alligators have small pores over their
Speaker 1: entire snouts that contain nerves sensitive to touch, heat, cold,
Speaker 1: and certain chemicals in their environments. Meanwhile, lizards like iguanas
Speaker 1: have a row of larger holes called foramina, aligned above
Speaker 1: their teeth that contain nerves and blood vessels. A therapod
Speaker 1: dinosaur skulls are more similar to the lizards, suggesting that
Speaker 1: their facial structures were closer to that of lizards with lips,
Speaker 1: so case closed. As with everything dinosaur related, paleontologists draw
Speaker 1: their conclusions based on ancient and incomplete data, and other
Speaker 1: dinoscholars aren't so sure about this whole t Rex lips situation.
Speaker 1: One Thomas Carr, a vertebrate paleontologist who has studied therapod
Speaker 1: facial structure, told Science that he didn't find the study persuasive.
Speaker 1: His own findings indicate that theropods snouts were tough, scaly,
Speaker 1: and devoid of soft tissue, and thus when it comes
Speaker 1: to lips more closely resembled crocodile snouts. It's also unclear
Speaker 1: whether exposure to the elements would have meaningfully damaged the
Speaker 1: teeth of t Rex. If the skeptics are correct, t
Speaker 1: Rex might have been perpetually smiling for the camera. After all,
Speaker 1: a new evidence is always being investigated. This won't be
Speaker 1: the first time that paleontologists and paleo artists have revised
Speaker 1: their working draft of what the t rex's mouth looked like,
Speaker 1: and it probably won't be the last. In the nineteen
Speaker 1: twenties and thirties, for example, t Rex was often depicted
Speaker 1: with lips, and until we found a mummified fossil of
Speaker 1: a t rex skull, we won't know for sure. We
Speaker 1: haven't even found any with skin patterning intact, so there's
Speaker 1: a possibility that t Rex had feathers like some of
Speaker 1: its smaller relatives. Today's episode is based on the article
Speaker 1: t Rex didn't Kiss and Tell, but may have had
Speaker 1: lips on how Stuffworks dot Com, written by Thomas Harlander.
Speaker 1: The brain Stuff is production of iHeartRadio in partnership with
Speaker 1: how Stuffworks dot Com and is produced by Tyler Klang.
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