Why T. rex has little arms

Scientists explain short dinosaur arms - 1st June 2026

Scientists have new ideas about Tyrannosaurus rex. This dinosaur had very small arms. The scientists studied its head and arms. They learned more information about them.

T. rex lived 68 to 66 million years ago. This dinosaur was 13 metres long. It was 4 metres tall. But its arms were a lot smaller than its body.

Nobody knows why T. rex had small arms. Did they use them for eating? Were they for finding a partner?

Scientists from Cambridge and London worked together. They studied 85 different types of dinosaur. These dinosaurs all ate meat. They came from 5 different groups.

The dinosaurs with small arms had big, strong heads. They used their heads to kill big animals. They didn't need their arms for this.

These dinosaurs' heads grew bigger. Their arms got smaller. But what were their arms for? Why did they keep them? Scientists hope to find out this information soon.