(CNN)Tyrannosaurs were fearsome predators in the dinosaur kingdom, but new research shows their hatchlings were about as big as a medium-sized dog.
Researchers studying the first-known fossils of tyrannosaur embryos suggest the dinosaurs were approximately three feet long when they hatched, according to a study from the University of Edinburgh, published Monday.
A team of paleontologists studied the fossilized remains of a tyrannosaurus embryo, namely a jaw bone and claw that were found in Canada and the US, respectively.
After producing 3D scans of the remains, researchers were able to predict that the dinosaurs would have hatched from eggs about 17 inches long.
The tyrannosaurs would have reached around 35 feet in length when fully grown. Left to right, a fully grown Albertsosaurus, an Albertosaurus embryo, a Daspletosaurus embryo.
Remains of tyrannosaurus eggs have never been found, but this finding could help paleontologists spot them in the future.
"Dinosaur babies are very rare," lead study author Greg Funston, a paleontologist at the University Edinburgh, told CNN, explaining that larger specimens are better represented in the fossil record because their bones were more durable.
<