Tyrannosaurus rex lived 66 million years ago and no human has ever seen one alive. How do we know how it – or any other long-extinct dinosaur – moved? This is part of a larger question in palaeontology: how do we understand the behaviours of extinct species? In general, we rely on information from fossils, tests using computer modelling, and comparisons to modern-day animals, especially birds (the descendants of dinosaurs) and crocodiles (the closest living cousins to dinosaurs).
Fossils can tell us certain things about dinosaur movement. Simply by looking at a skeleton, we can grasp the basics of whether the dinosaur walked on all fours, or only on its hind legs. Skeletons can also give us an indication of whether a dinosaur was likely to be slow or plodding, based on how robust the bones are and how the limbs are held.