Eurypterus
Eurypterus was a sea scorpion that lived in shallow seas more than 400 million years ago. It was about as long as a pencil and swam with two big paddles. It is the best known sea scorpion of all, and some of the finest fossils come from Estonia.

When did it live?
How big is it?
How long is it?
How big is Eurypterus compared to YOU?
Just maths in your browser. Nothing is saved or sent anywhere.
How fast is it?
Fun facts
More than 95 out of every 100 sea scorpion fossils ever found are Eurypterus.
The very first fossil, found in 1818, was mistaken for a catfish.
Fossils from Estonia are so well kept that scientists could dissolve the rock away and study the real old skin under a microscope.
It is the official state fossil of New York.
The biggest one ever found was about 60 centimetres long, much bigger than usual.
Most asked questions about Eurypterus
?Was Eurypterus a real scorpion?
No. It is called a sea scorpion because it looked a bit like one, but it was a different animal that lived in water.
?How big was Eurypterus?
Most were 13 to 23 centimetres long, about the size of a pencil.
?When did Eurypterus live?
About 432 to 418 million years ago, long before the dinosaurs.
For bug experts
- Scientific name
- Eurypterus
- Named by
- De Kay, 1825
- Group
- Prehistoric giants
- Family
- Eurypteridae
- Classification
- Eurypterida > Eurypteridae
- Also known as
- Sea scorpion
Where the facts come from
- Eurypterus (Wikipedia, CC BY-SA 4.0): what it looks like, where it lives, what it eats, sizes and fun facts, retold in simple words.
- Picture by Luis Fernández García. CC BY-SA 4.0, Wikimedia Commons. The round sticker of this bug is cut from the same picture.
If we got something wrong, sorry, we are bug fans, not a science journal. Tell us at [email protected] and we will fix it.