Tyrannosaurus

What it was like

Tyrannosaurus was a huge, heavy-headed hunter that walked on two legs. Its skull alone was massive, packed with thick, banana-sized teeth built for crushing bone as well as slicing meat. Its arms were short but strong, each ending in two clawed fingers. A full-grown Tyrannosaurus stretched to about 12.3 meters (40 feet) long and weighed around 8.4 metric tons.

Its bite was among the most powerful of any land animal that has ever lived. It most likely hunted plant eaters like hadrosaurs and young ceratopsians, and probably scavenged carcasses when it found them, as many predators do.

Its world

Tyrannosaurus lived in the Late Cretaceous, from about 72 to 66 million years ago, across what is now the western United States and Canada. Its fossils turn up in rock layers such as Hell Creek and Lance, alongside plant eaters like Triceratops, Ankylosaurus, and Pachycephalosaurus, and smaller hunters like Troodon.

Tyrannosaurus was among the last non-avian dinosaurs. It disappeared 66 million years ago, when an asteroid struck near what is now Chicxulub in Yucatan, Mexico, and triggered a mass extinction.

How it was found

Osborn named Tyrannosaurus in 1905, giving it a name that means tyrant lizard. Since then, paleontologists have logged about 75 fossil finds of this genus, more than almost any other large predatory dinosaur, which is why so much is known about how it lived.