The most famous of all the dinosaurs is also the most terrifying: Tyrannosaurus rex, or the King Tyrant Lizard. How fitting that the king of the dinosaurs inspired the King of the Monsters.

The T-Rex, the most famous of the predatory dinosaurs, dwelled in North America during the late Cretaceous era, the twilight of dinosaurs’ time on Earth. It was a theropod, a class of carnivorous dinosaurs that walked on two hind legs with shorter arms at the front of their bodies. T-Rex, Allosaurus, Velociraptors, all of these were theropods, and Godzilla’s body shape corresponds to theirs, particularly his snout and sharp teeth.

In 1954, it was believed that theropods walked upright, lifting their heads high and their tails dragging along the ground. You can see this not only in Godzilla’s lumbering posture, but also contemporary depictions of the T-Rex. It’s since been discovered that theropods were horizontally-shaped; their primary body mass was like a horizontal line, with the tail flowing through the air to balance their bodies as they walked.

However, Godzilla still walks like 1950s scientists expected a T-Rex to; since he’s not really a dinosaur, there’s no reason Godzilla’s depictions have to adhere to the latest paleontology.