Profile view of Tyrannosaurus rex
Kingdom Animalia
Phylum Chordata
Superclass Tetrapoda
Class Reptilia
Subclass Diapsida
Superorder Dinosauria
Order Saurischia
Suborder Theropoda
Superfamily Tyrannosauroidea
Family Tyrannosauridae
Subfamily Tyrannosaurinae
Genus Tyrannosaurus
1st Species Tyrannosaurus rex
Other attributes
Time Range 68-66 mya
Location United States of America, Canada
Name Meaning Tyrant reptile
Physical Dimensions 11.9-12.4 meters long
Weight 7.7-9.1 tonnes
Dietary Classification Carnivore

Comparison of T.rex specimens, with an 1.8 meter tall human for scale. Click to expand

Tyrannosaurus is a tyrannosaurid theropod dinosaur from the Late Cretaceous of the United States of America and Canada. It was officially named in 1905 by Henry Fairfield Osborn. It is the most famous dinosaur to exist (appearing in almost every piece of dinosaur-related media ever), and is also one of the most studied.


Tyrannosaurus was a bipedal dinosaur with a bulky body, moderately long legs, a long tail, and a large head with a mouth containing lots of big teeth. Perhaps the most defining traits of Tyrannosaurus were its tiny arms that bore two fingers on each hand; as well as this, unlike most other theropods (bipedal, mainly carnivorous dinosaurs), its eye sockets were placed near the front of its head, allowing for binocular vision. Its body would have been covered in scaly skin.


Tyrannosaurus was a predator, preying mainly on ceratopsids, hadrosaurs, and ankylosaurs as an adult, and subsisting on smaller theropods as well as pachycephalosaurs as a juvenile. Its teeth had knife-like serrations from back to back, and were designed for crushing bone, which would have been useful for penetrating the defenses of armored ornithischians like Ankylosaurus and Triceratops.


Tyrannosaurus had good olfactory (smelling) senses, and its forward-facing eyes would have allowed it to have binocular vision slightly better than that of a hawk; as well as this, it had a wide gape, and its huge jaws were able to exert a tremendous force when biting down on prey (allowing it to crush their bones). However, due to its relatively large mass, it was a slow runner (despite having leg proportions adapted towards swift movement); however, it was able to traverse and survey the wide Cretaceous landscape without expending energy, which was useful for keeping up with migrating prey. For a while, it has been suspected that Tyrannosaurus was an obligate scavenger; however, this has been disproved, as toothmarks of this dinosaur have been found on the damaged tail of an individual Edmontosaurus (even more interesting is that the bone started to heal), proving that the theropod was an active hunter. Another interesting thing to note is that Tyrannosaurus led a violent, cannibalistic lifestyle, often fighting with other members of its species and feeding on their carcasses; as well as this, once it killed a Triceratops, it would rip its head off its body right before feasting on its neck.

In popular cultureEdit

Since its discovery, Tyrannosaurus has become the most famous dinosaur of all time, overshadowing the earlier-discovered Allosaurus and Megalosaurus. It has managed to become the archetypal large theropod (and by extension, the archetypal dinosaur), and has appeared in many major pieces of media like The Lost World, King Kong, The Land Before Time, and Jurassic Park, where it is commonly depicted as a marauding brute willing to chase Triceratops, hadrosaurs, sauropods, Ankylosaurus, Stegosaurus, and humans over long distances in an attempt to capture and slaughter them. In documentaries like Walking with Dinosaurs and Prehistoric Park, it is portrayed as less persistent and more animalistic.

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