Plesiosaurus Facts for Kids
PLEE-zee-oh-SORE-us · its name means “near lizard”
🌊 Not a dinosaur: a sea reptile that lived at the same time
A long-necked sea reptile with four flippers, but not a dinosaur.
- 📏 size: not yet checked long
- ⚖️ weight: not yet checked
- 🕰️ the Jurassic
- 🍽️ fish
Plesiosaurus lived in the sea. It had a long neck and four flippers. It was not a dinosaur, but it lived with them.
Plesiosaurus was a reptile that lived in the sea at the same time as the dinosaurs, so it was not a dinosaur itself. It had a small head on a very long neck, a wide body and four flippers. It swam by flapping its flippers like underwater wings, and it came up to the surface to breathe air.
Plesiosaurs were a different group of reptiles from the dinosaurs, and they lived in the sea. Plesiosaurus had many more neck bones than a giraffe, and a small head with pointed teeth for catching fish and squid-like animals. Its first nearly whole skeleton was found by the fossil hunter Mary Anning on the shore at Lyme Regis in England. It looked so odd that a famous scientist at first thought it was a fake.
Every dinosaur number is scientists’ best guess from bones, so each one says where it came from.
How big was Plesiosaurus?
Plesiosaurus: no checked size yet, so there is nothing to draw. We only draw what a source says.
Plesiosaurus in numbers
| Wingspan | no checked number yet |
|---|---|
| Height at the hips | no checked number yet |
| Weight | no checked number yet |
| When it lived | no checked number yet |
| What it ate | fish and squid-like animals |
| Fossils found in | the coast of southern England, especially near Lyme Regis |
| What kind | a sea reptile: it swam in the sea while dinosaurs walked on land, and was not a dinosaur |
Wow!
- It was a reptile of the sea, not a dinosaur.
- Its neck had many more bones than a giraffe's neck.
- A famous scientist first thought its skeleton was a fake, because it looked so odd.
🦴 Plesiosaurus’s bones
Books about Plesiosaurus, free at the library
Ask a grown-up to tap the button: it shows where to borrow a book about Plesiosaurus for free.
Where was the land back then?
The continents were in different places when Plesiosaurus lived, in the Jurassic. Open Planet Earth, pick Drifting continents, and slide back in time to see where the land was.
🦖 Ride a Plesio in Dino DashThe game’s rare Nebula Plesio is a made-up version of this animal.
Its neighbours in time
Where these numbers come from
- Wikidata, Plesiosaurus (Q857081), checked 30 October 2026.
To read more: the Natural History Museum’s Dino Directory (see also, not copied).