Dino profile
T-Rex
the giant with tiny little arms
T-Rex was a big meat-eating dinosaur that walked on two legs. You can spot it by its huge head, its big teeth and its tiny little arms.
Its ID card
- Its name
- Its full name is Tyrannosaurus rex, “the tyrant lizard king”: Tyrannosaurus comes from the Greek words for “tyrant” and “lizard”, and rex means “king” in Latin. [1][2]
- Its weight
- Between about 5 and 8 tonnes, according to estimates. The biggest ones were probably over 8 tonnes. [1][2]
- What it ate
- Meat: other animals, and also animals that were already dead. [1]
- Its family
- The tyrannosaurids, big theropods: dinosaurs that walked on two legs. [1]
Big teeth, little arms
It had about sixty pointed teeth, with edges like a saw. They could be up to 20 centimeters long. The biggest one we know of is about 30 centimeters long with its root. [1][2]
Its bite was very powerful: according to the Natural History Museum in London, the strongest of all known land animals. [1]
Its arms were about 1 meter long, with two clawed fingers. They were small, but strong for their size. [2]
What were they for? Scientists don't agree. Maybe for getting back up after a fall, or for holding its food. [1]
A great sense of smell, scaly skin
A big part of its brain was used for smelling. Its sense of smell helped it find food. [1][2]
The pieces of skin that have been found show scales. There is no direct proof that it had feathers. If it did, they were probably only on its back. [1][2]
One of its cousins, Yutyrannus, did have feathers. [1][2]
How fast it could run is still debated. The London museum estimates about 22 km/h for an adult, and maybe more for a young one. [1]
Its discovery
In 1900, fossil hunter Barnum Brown finds a first skeleton in Wyoming, in the United States. In 1902, he finds another one in Montana. [1][2]
In 1905, paleontologist Henry Fairfield Osborn gives it its name. Later, people realized that some bones given another name in 1892 came from the same animal, but everyone already knew the name Tyrannosaurus: so it was kept. [1][2]
In 1990, Sue Hendrickson discovers an almost complete skeleton in South Dakota. It is called Sue, after her. It is about 85 or 90% complete, depending on the source. You can see it at the Field Museum, in Chicago. [2][3]
The growth marks in its bones show that Sue had reached adult size at around 19 years old, and lived about 28 years. [2][3]
Sources
The information on this page comes from these sources:
- Tyrannosaurus, Dino Directory, Natural History Museum, London (accessed November 5, 2026).
- Tyrannosaurus, Wikipedia (English), and the publications it cites: Osborn 1905, Brochu 2003, Erickson et al. 2004, Hutchinson et al. 2011, Bell et al. 2017 (accessed November 5, 2026).
- SUE the T. rex, Field Museum, Chicago (accessed November 5, 2026).