Coelophysis Facts for Kids
SEE-loh-FIE-sis · its name means “hollow form”
A slim, speedy early dinosaur with light, hollow bones.
- 📏 7.9 ft2.4 m1 long
- ⚖️ 51 lb23 kg1
- 🕰️ 201 to 252 million years ago201 to 252 million years ago2
- 🍽️ meat
Coelophysis was a slim dinosaur. It ran fast on two legs. Its bones were hollow, so it was light.
Coelophysis lived very early in the age of dinosaurs, in the Triassic. It had a long neck, a long tail, a narrow head full of small, sharp teeth, and hands with grasping fingers. Its light, hollow bones helped it run fast and catch lizards and other small animals.
Coelophysis is one of the best known early dinosaurs, and it lived long before T. rex. Many of its skeletons were found together at Ghost Ranch in New Mexico, so scientists think these animals may have lived in groups. The hollow bones that gave it its name are something birds have too, because birds are living dinosaurs. Coelophysis is the state fossil of New Mexico.
Every dinosaur number is scientists’ best guess from bones, so each one says where it came from.
How big was Coelophysis?
Coelophysis in numbers
| Length (nose to tail) | 7.9 ft2.4 m1estimate |
|---|---|
| Height at the hips | no checked number yet |
| Weight | 51 lb23 kg1estimate |
| When it lived | 201 to 252 million years ago201 to 252 million years ago2the whole Triassic Period |
| What it ate | small lizards and other small animals |
| Fossils found in | the American Southwest, especially Ghost Ranch in New Mexico |
| What kind | a theropod: a two-legged dinosaur, the group birds came from |
Wow!
- Its name means hollow form, for its hollow bones.
- Many skeletons were found together at Ghost Ranch in New Mexico.
- It is the state fossil of New Mexico.
🦴 Coelophysis’s bones
Books about Coelophysis, free at the library
Ask a grown-up to tap the button: it shows where to borrow a book about Coelophysis for free.
Where was the land back then?
The continents were in different places when Coelophysis lived, 201 to 252 million years ago. Open Planet Earth, pick Drifting continents, and slide back in time to see where the land was.
Its neighbours in time
Where these numbers come from
- National Park Service, Petrified Forest National Park (Museum Detectives lesson plan), checked 30 October 2026.
- National Park Service, National Natural Landmarks, checked 30 October 2026.
- Wikidata, Coelophysis (Q309392), checked 30 October 2026.
To read more: the Natural History Museum’s Dino Directory (see also, not copied).