Allosaurus

Say it: AL-oh-SORE-us

Name means: “different lizard”1

Ate: MeatOther meat-eatersLate Jurassic to Early Cretaceous

Allosaurus was a huge meat-eating dinosaur that lived during the Late Jurassic period. It had a big head full of sharp, serrated teeth and walked on two strong legs. It was one of the top predators of its time, hunting large plant-eaters.1

Lived

162 to 137 million years ago3

Late Jurassic to Early Cretaceous

Fossils found in

North America (Morrison Formation), Portugal, and possibly Germany, Tanzania, and Switzerland1

Food

Meat1 2

Length

7.5 to 9 m1

for A. fragilis, largest specimens estimated at 9 meters

Artist's life restoration of Allosaurus — How Allosaurus may have looked, by Fred Wierum. CC BY-SA 4.0, via Wikimedia Commons. Scientists still argue about colours and details.

When did it live?

Triassic

Jurassic

Cretaceous

252 million years ago20114566, the asteroid

How big was it?

cool stuff

Fun facts

Allosaurus had dozens of sharp, serrated teeth in its mouth, perfect for slicing meat.1

Its name means 'different lizard' because its backbone bones were light and hollow, which was unusual for a dinosaur of its size.1

Allosaurus lived from about 155 to 143 million years ago, during the Late Jurassic period.1

It was one of the most common large predators in its ecosystem, and many fossils have been found in the Morrison Formation.1

Some scientists think Allosaurus may have hunted in packs, but others think it was a solitary predator that only gathered in groups sometimes.1

Allosaurus had small, three-fingered hands, but its legs were large and powerful for running after prey.1

Myth buster

Myth: Some people think Allosaurus was a slow, clumsy scavenger.

Truth: Scientists think Allosaurus was a fast and active predator, with strong legs and sharp teeth for hunting live prey.1

For dino experts

Scientific name: Allosaurus
Named by: Marsh 18773
Group: Other meat-eaters
Family / clade: Allosauroidea3
Classification: Theropoda > Allosauroidea3
Age of the rocks: 162 to 137 million years (Oxfordian to Berriasian)3
Rock formations: Morrison, Alcobaça, Lourinhã3
Countries: USA, Portugal, France, Germany3
Fossil records: 147 in the Paleobiology Database3
Also known as: Antrodemus, Apatodon, Creosaurus, Epanterias, Labrosaurus, Saurophagus (older names now counted as the same animal)3
Discovery: The first fossils that could be clearly assigned to Allosaurus were described in 1877 by Othniel C. Marsh. He named it Allosaurus, meaning 'different lizard'.1
Still debated: Scientists still debate whether Allosaurus hunted in cooperative packs or was a solitary predator that sometimes gathered in groups.1

Where the facts come from

Allosaurus (en.wikipedia.org)
PBDB Taxon (paleobiodb.org)
Allosaurus 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 hello@dinowiki.app and we will fix it.