Tyrannosaurus Rex Dinosaur Facts, Pictures & In-Depth Information

Tyrannosaurus rex dinosaur facts, with pictures and information. An in-depth guide to this famous Cretaceous Period predator.

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Tyrannosaurus Rex Dinosaur Facts

Tyrannosaurus rex, or T. rex for short, was a predatory theropod dinosaur. One of the largest land predators that ever lived, Tyrannosaurus rex was longer than a bus, weighed more than five cars, and was equipped with incredibly powerful jaws. This fearsome carnivore roamed western North America during the Late Cretaceous.

Tyrannosaurus rex with Parasaurolophus in background
Tyrannosaurus rex with Parasaurolophus in background

You've no doubt seen Tyrannosaurus rex in films such as Jurassic Park. On this page you'll meet the real Tyrannosaurus rex dinosaur...

What Type Of Dinosaur Was Tyrannosaurus Rex?

Tyrannosaurus rex was a theropod dinosaur. Most theropods were, like Tyrannosaurus rex, bipedal predators.

Bipedal = walks on two legs

All theropods (including Tyrannosaurus rex) belonged to a larger group of dinosaurs called Saurischia.

You can find out more about theropods, saurischians, and other types of dinosaurs on these pages:

Tyrannosaurus rex belonged to the family Tyrannosauridae, along with other large, meat-eating dinosaurs, such as Albertosaurus, Gorgosaurus, Daspletosaurus and Tarbosaurus.

What Did Tyrannosaurus Rex Look Like?

Tyrannosaurus rex dinosaur

Tyrannosaurus rex was a large, bipedal dinosaur. Its head was huge, and its powerful jaws held up to 60 sharp teeth. Tyrannosaurus rex’s long tail provided a counterbalance for its huge head.

The skull of Tyrannosaurus rex had several large holes that helped to lower its weight.

Tyrannosaurus rex’s arms were extremely short, and each hand had two clawed fingers.

Each of Tyrannosaurus rex’s feet had three main claws, with a fourth, smaller claw positioned further up the leg.

Early depictions showed Tyrannosaurus rex in an upright posture, but we now know that the dinosaur walked with its body held horizontally.

How Many Teeth Did Tyrannosaurus Rex Have?

Tyrannosaurus rex had from 54 to 60 teeth.

Tyrannosaurus Rex Skull

The largest Tyrannosaurus rex tooth found is over 30 cm / 12 in. long (including its root).

Tyrannosaurus Rex Arms

Paleontologists don’t know for certain what Tyrannosaurus rex used its arms for.

Although short, Tyrannosaurus rex’s arms are thought to have been very strong.

Tyrannosaurus rex’s tiny arms weren't long enough to pass food to the dinosaur’s mouth.

Possible uses for Tyrannosaurus rex's arms include: helping the dinosaur get onto its feet from a resting position; and preventing prey from escaping.

How Big Was Tyrannosaurus Rex?

Tyrannosaurus rex was one of the largest land predators that ever lived. It was longer than a bus and weighed more than five family cars.

Standing around 3.96 m (13 ft) tall at the hips, Tyrannosaurus rex would have been able to peer into your upstairs windows with ease!

“Scotty”, the largest Tyrannosaurus rex specimen yet discovered, is estimated to have been 13 meters / 43 feet in length, and 8.87 metric tonnes / 9.77 short tons in weight, when alive.

Was Tyrannosaurus Rex The Biggest Dinosaur That Ever Lived?

Tyrannosaurus rex was not the biggest dinosaur that ever lived. Despite being one of the largest carnivorous dinosaurs, Tyrannosaurus rex would have been dwarfed by some of the huge herbivorous sauropod dinosaurs such as Brontosaurus and Argentinosaurus.

Sauropods such as Brontosaurus were bigger and heavier than Tyrannosaurus rex.

With a maximum estimated length of 130 feet / 40 metres, Argentinosaurus was over three times as long as Tyrannosaurus rex!

Several other meat-eaters, such as Giganotosaurus, Carcharodontosaurus and Spinosaurus, are thought to have either equaled or surpassed Tyrannosaurus rex in size.

How Fast Could Tyrannosaurus Rex Run?

Paleontologists have calculated that Tyrannosaurus rex would have been able to run at speeds of up to 25 mph / 40.23 km/h.

That’s not quite as fast as Usain Bolt, the world’s fastest human, who could run at 27.79 mph / 44.72 km/h, but much faster than most other people.

When Did Tyrannosaurus Rex Live?

Tyrannosaurus rex lived in the Late Cretaceous. The species first appeared around 68 million years ago (mya), and went extinct 66 mya.

The Late Cretaceous is the last (i.e. the most recent) of the two epochs that make up the Cretaceous Period.

“Epochs” and “periods” are units in the geologic time scale, which is a way that geologists measure Earth’s history.

Why Did Tyrannosaurus Rex Go Extinct?

Around 66 mya, Earth was hit by a giant asteroid. Scientists think that the explosion caused a change in the world’s climate, which resulted in the extinction of Tyrannosaurus rex and all of the other dinosaurs (and many other types of animals and plants).

Tyrannosaurus rex and pterosaurs
Tyrannosaurus rex was one of the last living dinosaurs.

Because this catastrophe marked the end of the Cretaceous Period and the beginning of the Paleogene Period, it is known as the “Cretaceous-Paleogene Extinction Event”.

Where Did Tyrannosaurus Rex Live?

Tyrannosaurus rex lived in what is now western North America.

Over vast amounts of time, continents gradually move across the globe, sometimes merging with other continents or splitting apart to form new continents.

Although the world’s continents were beginning to settle into their modern-day positions when Tyrannosaurus rex was alive, North America was still split down the middle by a shallow sea known as the Western Interior Seaway.

The Western Interior Seaway divided North America into two large island continents: Laramidia to the west, and Appalachia to the east.

Tyrannosaurus rex lived on Laramidia, which would become western North America when the Western Interior Seaway retreated.

Tyrannosaurus Rex Fossil Locations

Over 50 Tyrannosaurus rex specimens have been discovered. Many of these were found at the famous Hell Creek Formation, a rock formation that covers parts of Montana, North Dakota, South Dakota, Wyoming in the United States.

Tyrannosaurus Rex Sue
"Sue" the Tyrannosaurus was discovered in the Hell Creek Formation. Photo: Jonathan Chen (cropped / resized by ActiveWild.com), CC BY-SA 4.0, via Wikimedia Commons

Most Tyrannosaurus rex fossils have been found in the USA, but some have been discovered in Canada.

Many Tyrannosaurus rex specimens have been given names. These include “Scotty”, “Sue”, “Black Beauty” and “Trix”.

How Strong Were Tyrannosaurus Rex Jaws?

Tyrannosaurus rex is thought to have one of the strongest bite forces of all animals.

By studying the jaws of Tyrannosaurus rex specimens, and comparing them with those of living animals, scientists calculate that Tyrannosaurus rex’s jaws were over twice as powerful as those of a saltwater crocodile! (The saltwater crocodile has one of the most powerful bites of all living animals!)

What Did Tyrannosaurus Rex Eat?

Tyrannosaurus rex was the apex predator in western North America at the end of the Cretaceous Period. The diet of Tyrannosaurus rex would likely have consisted of just about any other dinosaur it could overcome.

Dinosaurs that lived with Tyrannosaurus rex include Edmontosaurus, Triceratops, Ankylosaurus, Pachycephalosaurus and smaller theropods such as Ornithomimus; it's likely that all were hunted by Tyrannosaurus rex.

Fossil evidence tells us that Triceratops and Tyrannosaurus rex were adversaries. Sometimes Triceratops may even have come out on top!

Bite marks on Tyrannosaurus rex skeletons are thought to have been made by other Tyrannosaurus rex. Tyrannosaurus rex may have fought among themselves to establish dominance, or they may have even eaten each other!

Was Tyrannosaurus Rex A Scavenger?

Several paleontologists have suggested that Tyrannosaurus rex, with its acute sense of smell and bone-crushing bite force, may have been primarily a scavenger. Although Tyrannosaurus probably hunted its own food, it is likely that scavenged food also made up at least part of its diet.

Did Tyrannosaurus Rex Have Feathers?

To this day, no feathered Tyrannosaurus rex specimens have been found. However, some scientists think that the dinosaur may have had feathers, at least when young.

Other scientists think that even full grown Tyrannosaurus rex would have had feathers. This is because specimens of related and similarly-sized dinosaurs have been found that do have feathers.

Tyrannosaurus Rex Name

Tyrannosaurus means “tyrant lizard” and “Rex” means “king”. Put together, the name Tyrannosaurus rex means ‘King Tyrant Lizard’; a fitting name for this fearsome dinosaur!

The man who named Tyrannosaurus rex was American palaeontologist Henry Fairfield Osborn. Osborn was president of the American Museum of Natural History. He named Tyrannosaurus rex in 1905.

As with all two word scientific species names, the first word (in this case Tyrannosaurus) can be shortened to its initial if the name is used repeatedly. This is why Tyrannosaurus rex is often abbreviated to T. Rex. Another convention is to write species names in italics.

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