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Ceratosaurus

Name means: “horned lizard”1
Ate: MeatOther meat-eatersLate Jurassic to Early Cretaceous

Ceratosaurus was a meat-eating dinosaur that lived in North America and Europe during the Late Jurassic Period. It had a horn on its snout and a row of small bony plates along its back. It was a rare hunter that lived alongside the more common Allosaurus.1

Lived
158 to 143 million years ago5
Late Jurassic to Early Cretaceous
Fossils found in
Colorado and Utah, USA, and Portugal15
Food
Meat1
Length
6 to 7 m1
Weight
900 kg to 1.36 tonnes12

When did it live?

Triassic
Jurassic
Cretaceous
252 million years ago20114566, the asteroid

How big was it?

How long was it?

Ceratosaurus about 7 m longA bicycle about 1.8 mA car about 4.5 mAn elephant, the biggest land animal today about 6.5 mA house about 10 m

How heavy was it?

as heavy as 45 big dogs
as long as 7 dogs nose to tailas long as 39 bananas end to endas heavy as 270 watermelons

How big was Ceratosaurus compared to YOU?

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cool stuff

Fun facts

1

Ceratosaurus is the only known meat-eating dinosaur that had a horn on its snout.2

2

Unlike other large theropods, Ceratosaurus had only three teeth in its premaxilla (the front of the upper jaw).2

3

The first nearly complete skeleton was found in 1883 by a Colorado farmer named Marshall Parker Felch.1

4

Ceratosaurus fossils are much rarer than those of Allosaurus, which lived at the same time.1

5

Some scientists think Ceratosaurus may have eaten aquatic animals like fish and turtles.1

6

All known Ceratosaurus individuals were found alone, so there is no evidence they hunted in groups.1

AI-madeAI-made picture of Ceratosaurus
An AI-made picture of how Ceratosaurus might have looked, made by a computer from what scientists know. It is a guess: the real animal may have looked different, and nobody knows its true colours.
you asked

Most asked questions about Ceratosaurus

?How big was Ceratosaurus?

Ceratosaurus was a medium-sized theropod. The original specimen was about 5.3 to 5.7 metres (17 to 18.7 feet) long, while a larger specimen reached around 7 metres (23 feet).3

?What did Ceratosaurus eat?

Ceratosaurus was a carnivore, a meat eater. It may have preyed on plant-eating dinosaurs, and some scientists suggested it also ate aquatic prey like fish and turtles, though that idea has been rejected by more recent studies.34

?Did Ceratosaurus have feathers?

The sources do not mention feathers on Ceratosaurus. It is known to have had a row of small bony plates (osteoderms) along its back, but no feather impressions have been found.3

?Was Ceratosaurus bigger than Allosaurus?

No, Ceratosaurus was smaller. Allosaurus was a larger theropod, while Ceratosaurus was medium-sized, around 5.3 to 7 metres long. The sources do not give an exact size for Allosaurus, but they describe Ceratosaurus as rarer and smaller.32

?Why did Ceratosaurus have a horn?

The horn on its snout was probably not used as a weapon. Scientists think it was used for display, like to attract mates or show off.3

?Could Ceratosaurus swim?

Some scientists once thought Ceratosaurus could swim because of its deep tail, but later studies rejected that idea. The deep tail is not unique to swimming dinosaurs.3

?When did Ceratosaurus live?

Ceratosaurus lived during the Late Jurassic period, around 155 million years ago, in North America and Europe.3

?Where was Ceratosaurus found?

The first nearly complete skeleton was found in Garden Park, Colorado, in the Morrison Formation. Later, fossils were found in Portugal, and fragmentary remains were reported from Tanzania, Uruguay, and Switzerland, but those are not widely accepted.3

?How many teeth did Ceratosaurus have?

Ceratosaurus had only three teeth in its premaxilla, the front part of the upper jaw. This is unusual among large meat-eating dinosaurs.2

?Did Ceratosaurus hunt in packs?

There is no evidence that Ceratosaurus hunted in groups. All known individuals were found alone, so scientists think it was a solitary hunter.1

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Myth buster

Myth: Ceratosaurus hunted in packs like wolves.

Truth: All known Ceratosaurus fossils were found alone, so scientists think it was a solitary hunter.1

For dino experts

Scientific name
Ceratosaurus
Named by
Marsh 18845
Group
Other meat-eaters
Family / clade
Ceratosauria5
Classification
Theropoda > Ceratosauria5
Age of the rocks
158 to 143 million years ()5
Rock formations
Morrison, Tendaguru, LourinhΓ£5
Countries
USA, Portugal, Tanzania, Uruguay5
Fossil records
29 in the Paleobiology Database5
Discovery
The first Ceratosaurus fossil was found in 1883 by Colorado farmer Marshall Parker Felch. Scientist Othniel Charles Marsh studied the bones and named the dinosaur Ceratosaurus in 1884.15
Still debated
Scientists are not sure whether fossils found in Africa and South America truly belong to Ceratosaurus or to a different dinosaur.1

Where the facts come from

  1. Ceratosaurus | Natural History Museum (nhm.ac.uk)
  2. Ceratosaurus - Dinosaur National Monument (U.S. National Park Service) (nps.gov)
  3. Ceratosaurus (en.wikipedia.org)
  4. enchantedlearning.com (enchantedlearning.com)
  5. Ceratosaurus in The Paleobiology Database (CC BY 4.0): age, places, rock formations, classification.

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