Tyrannosaurus rex Facts for Kids
tie-RAN-oh-SORE-us REX · its name means “tyrant lizard king”
One of the biggest meat-eating dinosaurs, with a huge head and tiny arms.
- 📏 40 to 43 ft12 to 13 m1 long
- ⚖️ 8 to 9 tons7.3 to 8.2 tonnes1
- 🕰️ 66 to 68 million years ago66 to 68 million years ago1
- 🍽️ meat
T. rex walked on two big legs. It had a huge head and tiny arms. It lived a very long time ago.
Tyrannosaurus rex had a giant head, strong jaws and teeth with jagged edges like a steak knife. Its arms were short but strong, with two fingers each. Its long, heavy tail balanced its big head as it walked.
T. rex lived at the very end of the age of dinosaurs. Scientists study its fossils to learn how it grew: young ones were slim and fast, and grown-ups were much bulkier. It had a powerful sense of smell, and its eyes faced forward a little, which may have helped it judge distance.
Every dinosaur number is scientists’ best guess from bones, so each one says where it came from.
How big was Tyrannosaurus rex?
Tyrannosaurus rex in numbers
| Length (nose to tail) | 40 to 43 ft12 to 13 m1a grown-up, nose to tail; scientists' estimate |
|---|---|
| Height at the hips | 12 to 13 ft3.7 to 4 m1at the hips |
| Weight | 8 to 9 tons7.3 to 8.2 tonnes1up to; scientists' estimate |
| When it lived | 66 to 68 million years ago66 to 68 million years ago1the Late Cretaceous |
| What it ate | other dinosaurs, such as Triceratops and duck-billed dinosaurs |
| Fossils found in | western North America: Montana, Wyoming and the Dakotas |
| What kind | a theropod: a two-legged dinosaur, the group birds came from |
Wow!
- Its arms were tiny, but each one was strong.
- T. rex had teeth with jagged edges, like a steak knife.
- Some of the best T. rex fossils come from Montana and South Dakota.
🦴 Tyrannosaurus rex’s bones
Books about Tyrannosaurus rex, free at the library
Ask a grown-up to tap the button: it shows where to borrow a book about Tyrannosaurus rex for free.
Where was the land back then?
The continents were in different places when Tyrannosaurus rex lived, 66 to 68 million years ago. Open Planet Earth, pick Drifting continents, and slide back in time to see where the land was.
🦖 Ride a Rex in Dino DashThe game’s rare Lava Rex and Cosmic T-Rex are made-up versions of this animal.
Its neighbours in time
Where these numbers come from
- USDA Forest Service, Dakota Prairie Grasslands: prehistoric animals, checked 30 October 2026.
- Wikidata, Tyrannosaurus rex (Q14332), checked 30 October 2026.
To read more: the Natural History Museum’s Dino Directory (see also, not copied).