Top hunter of the Jurassic
It was the commonest large meat-eater of its time and place.
Jurassic giants · Theropods
Allosaurus
Different lizard · AL-oh-SORE-us
A large hunter with a big head, a small horn in front of each eye, three-clawed hands and a long tail.
- Size
- 8.5 to 12m long; 1.5 to 2 tonnes
- Lived
- About 155 to 145 million years ago
- Found in
- Western USA, and Portugal
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To scale
How big was it?
The bars are drawn to the same scale. On these pages the animals are sized in proportion to each other as far as a screen allows: the giants are shrunk a little and the smallest are enlarged, so that you can see them all.
Good to know
Six things about the allosaurus
A hatchet bite
It could open its jaws very wide and may have struck downwards with its upper teeth like an axe.
Big Al
One skeleton, called Big Al, shows at least nineteen injuries, including broken ribs and an infected toe.
New teeth for old
Like all meat-eating dinosaurs it grew new teeth all its life to replace those it lost.
A quarry full of them
At one quarry in Utah the bones of more than forty-six Allosaurus were found together.
Useful arms
Its arms were strong, with three large curved claws for gripping prey.
The real thing
Photos of the allosaurus
Photos are from Wikimedia Commons, used under the free licences shown. They have been resized, and cropped where they appear in link previews.
What it ate
Plant-eating dinosaurs, including Stegosaurus and young long-necks.
How we know
It is one of the best-known meat-eaters, from thousands of bones and several nearly complete skeletons.
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