Artist's reconstruction · realistic art coming in a later version
Dimetrodon
die-MET-ruh-don
“Two Measures of Teeth”
Before DinosaursWhen
Early Permian
Where
North America
Size
Up to 15 ft long
Diet
Meat
6 Facts
1–6- Dimetrodon is famous for the huge sail on its back, held up by long spines.
- It is not a dinosaur — and it lived about 40 million years before the first dinosaur appeared.
- Surprisingly, it’s more closely related to mammals (including us) than to reptiles or dinosaurs.
- Its name means “Two Measures of Teeth” because it had two different sizes of teeth — rare for its time.
- The sail may have helped it warm up in the sun or show off to others.
- It was the top predator of its world, hunting other early reptiles and amphibians.