You are here: Prehistoric > Dinosaur species > Allosaurus


Allosaurus Allosaurus was a giant theropod, one of the largest before the appearance of the tyrannosaurs about 70 million years later. It lived in the open woodlands of Jurassic North America, preying on the sauropods and other plant-eaters, such as Stegosaurus, Camptosaurus and Dryosaurus, that shared its habitat. Walking on two huge hindlegs, it had three, large, bird-like, clawed toes on each foot. Its arms were relatively short but muscular, ending in three-fingered claws. Its massive head had ridges above each of its eyes and another running down to the tip of its snout. Lining its powerful jaws were 60 long, curved, dagger-like teeth.

An Allosaurus threatens a group of Dryosaurus.
Allosaurus tears at the flesh of a Camarasaurus carcass.

Lone hunter?

Palaeontologists are not yet sure whether Allosaurus was a lone hunter or whether it hunted in a pack. It possibly scavenged (fed on animals that were already dead) as well as killing them itself. Whether it hunted alone or in a group, its speed, sharp teeth and strong claws would have been effective weapons. Allosaurus could have held its victim down with its claws as it bit off chunks of flesh.

The Cleveland-Lloyd Dinosaur Quarry in Utah could once have been a Jurassic “predator trap”. Usually, plant-eaters outnumber big predators. But here, fossil remains of over 40 Allosaurus have been found—many more than their victims. Palaeontologists think that plant-eaters trapped in mud pools may have unwittingly lured predators to their deaths.

Q-files now has new sections specially written for younger readers. They are: Living world, Earth, Science, Human body, Prehistoric life, Space, History, Geography and Technology.

Find the answer