Baby tyrannosaur dinosaurs were the size of dogs, embryo fossils show

Tyrannosaur dinosaurs roamed the Earth long before baby photos became a thing, so all we have is the fossil record to understand what they looked like when they first started. It’s been a difficult quest, but finding the “earliest known fossils of tyrannosaur embryos” helps create a picture.

A research team led by University of Edinburgh paleontologist Greg Funston studied a tiny jaw bone and claw fragments that belonged to cousins ​​of the famous Tyrannosaurus rex. The team created 3D scans to analyze the fossils and determined that the dinosaurs would have been 3 feet (about 1 meter) long when they hatched.

The team published their results in the Canadian Journal of Earth Sciences on Monday. “Tyrannosaurid eggs and embryos remain elusive, and juvenile specimens – although known – are rare,” the newspaper said. Funston suggested that it was possible for tyrannosaurs to lay soft-shelled eggs that would not be easily preserved as fossils.

Although the eggs have still not been found, the fragments of fossil embryos are revealing. The team’s work suggests that the eggs were around 43 centimeters long and that the young would be about the size of Border Collie dogs when they took their first steps.

Tyrannosaurs have dominated dinosaur popularity due to their large size, small arms, and predatory nature. They could be up to 12 meters long, which makes imagining them as little dog-sized babies seem pretty wild.

“It might sound like a lot, but remember they would’ve been curled up in an egg,” Funston wrote in a blog post.

“These bones are the first window into the early lives of tyrannosaurs and they tell us about the size and appearance of baby tyrannosaurs,” Funston said in a statement Monday. “We now know that they would have been the largest hatchlings to ever emerge from eggs, and they would have looked remarkably like their parents – two good signs for finding more material in the future.”