Tyrannosaurus’s starring role in the movie Jurassic Park confirmed its status as the most fearsome and famous dinosaur of all. Though not the largest carnivore ever to walk on land, it was the biggest of its time, and the strength of its bite was greater than that of any other land animal. Some experts think Tyrannosaurus was a scavenger as much as a killer, its huge jaws and teeth adapted to eating bones.
■ When: 70–65 million years ago (Late Cretaceous)
■ Fossil location: N. America
■ Habitat: Forests and swamps
■ Length: 39 ft (12 m)
■ Diet: Flesh
As long as a bus and twice the weight of an elephant, Tyrannosaurus was undoubtedly the top predator in its environment. Deep holes in the bones of prey such as Triceratops and Edmontosaurus show that Tyrannosaurus used its immensely powerful jaws and bone-piercing teeth as its main weapons. Small victims were probably shaken apart; larger animals were crippled by horrible injuries. Holding the body down with a foot, Tyrannosaurus used its huge neck muscles to tear off mouthfuls of flesh and bone with its mouth, before swallowing it all.
About 30 Tyrannosaurus fossils have been found, incuding several skeletons, though none is complete. Skin impressions show adults had scaly skin, but babies are likely to have had fluffy feathers like those of smaller tyrannosauroids.
Most carnivorous dinosaurs have blade-like teeth with sawtooth edges, but those of Tyrannosaurus were huge, pointed spikes that could pierce skin, muscle, and bone.
Tyrannosaurus had tiny arms and odd hands with just two clawed fingers each. The arms could not reach the mouth or even each other, but they were very strong. Perhaps Tyrannosaurus dug its claws into victims while holding them in its mouth to stop them from struggling free.
The hind legs were long, with powerful thigh muscles but slender ankles and feet. Their athletic build suggests Tyrannosaurus could run very fast, though perhaps it did so only rarely, since a high-speed fall could have proved fatal for such a heavy animal.