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Dryosaurus

Say it: DRY-oh-SORE-us

Name means: “oak lizard, named after the Greek word for oak tree”1

Ate: PlantsBeaked plant-eatersLate Jurassic to Early Cretaceous

Dryosaurus was a speedy, plant-eating dinosaur that lived in the Late Jurassic period. It had a long neck, strong legs, and a stiff tail that helped it balance while running. It probably used its speed to escape from big predators like Allosaurus.2

Lived

155 to 143 million years ago5

Late Jurassic to Early Cretaceous

Fossils found in

Western United States (Colorado, Utah, Wyoming), and also in France, Germany, and Portugal2 5

Food

Plants2 5

Length

3 to 4 m2 1

estimated, no known adult specimens

Weight

100 kg2

Height

1.7 m3

at the hips

When did it live?

Triassic

Jurassic

Cretaceous

252 million years ago20114566, the asteroid

How big was it?

How long was it?

How tall was it?

at the hips

How heavy was it?

as heavy as 3 big dogs

as long as 4 dogs nose to tailas long as 22 bananas end to endas heavy as 20 watermelonsabout as tall as a door

How big was Dryosaurus compared to YOU?

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cool stuff

Fun facts

Dryosaurus had five fingers on each hand, but its arms were short. Its long legs and stiff tail made it a fast runner.2

The name Dryosaurus means 'oak lizard', but it was named after the forest where it lived, not because its teeth looked like oak leaves.2

Some scientists think Dryosaurus had cheek-like structures to keep food in its mouth while chewing.2

Dryosaurus lived alongside giant sauropods like Diplodocus and Brachiosaurus, as well as predators like Allosaurus and Ceratosaurus.2

The largest Dryosaurus specimen was later identified as a different species, so the true adult size of Dryosaurus is still unknown.2

Dryosaurus fossils have been found in the Morrison Formation, which is famous for the 'Bone Wars' rivalry between paleontologists Marsh and Cope.2

AI-made picture of Dryosaurus — An AI-made picture of how Dryosaurus 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 Dryosaurus

?How big was Dryosaurus?

Based on known specimens, Dryosaurus reached up to 3 metres (9.8 ft) long and weighed up to 100 kilograms (220 lb). As no fully mature specimens have been found, the true adult size remains unknown.2

?What did Dryosaurus eat?

Dryosaurus was a plant-eating dinosaur. It ate low-growing vegetation in ancient floodplains, using its beak and cheek teeth.2 1

?When did Dryosaurus live?

Dryosaurus lived during the Late Jurassic period, about 155 to 145 million years ago.1

?Where was Dryosaurus found?

Dryosaurus fossils have been found in the western United States, including Wyoming, Utah, and Colorado. Fossils have also been identified in Tanzania.2 1

?How fast could Dryosaurus run?

Dryosaurus was a quick and agile runner with strong legs. It probably relied on its speed to escape predators, but no exact speed is known.2

?Did Dryosaurus have feathers?

The sources do not mention feathers on Dryosaurus. It is described as having a horny beak and cheek teeth, but no feather impressions have been found.2

?Was Dryosaurus bigger than a human?

Dryosaurus was about 3 metres (9.8 ft) long, which is longer than a human is tall, but it weighed up to 100 kilograms (220 lb), which is comparable to a large adult human.2

?Why is it called Dryosaurus?

Dryosaurus means 'tree lizard' or 'oak lizard'. It was named after the forested habitat where it lived, not because its teeth looked like oak leaves.2 4

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Myth buster

Myth: Some people think Dryosaurus was named because its teeth looked like oak leaves.

Truth: Actually, the name comes from the Greek word for 'oak' because it lived in forests, not because of its teeth.2

For dino experts

Scientific name: Dryosaurus
Named by: Marsh 18945
Group: Beaked plant-eaters
Family / clade: Dryosauridae5
Classification: Ornithischia > Ornithopoda > Iguanodontia5
Age of the rocks: 155 to 143 million years (Kimmeridgian / Tithonian)5
Rock formations: Morrison, Marnes de Bléville, Lourinhã5
Countries: USA, France, Portugal, Germany5
Fossil records: 24 in the Paleobiology Database5
Discovery: The first Dryosaurus fossils were found in 1876 by Samuel Wendell Williston in Wyoming, USA. Othniel Charles Marsh named it Laosaurus altus in 1878, then gave it its own genus, Dryosaurus, in 1894.2
Still debated: Scientists are still debating the true adult size of Dryosaurus because no adult specimens have been found yet.2

Where the facts come from

Dryosaurus | Natural History Museum (nhm.ac.uk)
Dryosaurus (en.wikipedia.org)
Dryosaurus Fact Sheet (enchantedlearning.com)
Dryosaurus altus (U.S. National Park Service) (home.nps.gov)
Dryosaurus in The Paleobiology Database (CC BY 4.0): age, places, rock formations, classification.

Every fact on this page has a number that points to its source. If we got something wrong, sorry, we are dino fans, not a science journal. Tell us at [email protected] and we will fix it.

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