Paleontologists know very little about Tyrannosaurus rex babies. Given how long these iconic carnivores have loomed over the public imagination, it might surprise you to learn that the first fossilized remains of an embryo belonging to any member of the tyrannosaurid family was only first confirmed in the peer-reviewed literature back around 2021. It’s a shame we didn’t know about this sooner (Spielberg will be kicking himself), but it turns out that the baby T. rex was a vicious little miscreant right out of the gate. A new study published this month in the journal Biology has analyzed fossils from two tyrannosaurid hatchlings, some classic T. rex and others from its close cousin Gorgosaurus libratus. Both species, the researchers found, displayed persuasive dental and vascular evidence that their little infant progeny were actually quite active and quite lethal. And they really were small: At 5.5 pounds (2.5 kilograms), baby T. rex was no bigger than a house cat. “Tyrannosaurus were unsafe at any size,” study co-author and Oklahoma State University anatomy professor Eric Snively said in a statement. “Babies were quickly out of the nest and killing the heck out of things.”
“The babies were smashing into the bones of their food, just like giant adults,” according to Snively, whose work applies biomedical engineering and 3D imaging to better understand the anatomy of groups as diverse as dinosaurs and human athletes.
