Creature information
Scientific name : Allosaurus fragilis
Time period : Late Jurassic
Primary diet : Carnivore
In the documentary
Fatalities caused : One Ceratosaurus

One Apatosaurus (Indirectly)

Allosaurus was a theropod dinosaur from Late Jurassic North America and Portugal. The name Allosaurus (al-o-soar-us) means "different lizard". It measured over 43 feet long and weighing 4 tons, it was considered one of, if not only, the largest predator that lived on the land, in the Late Jurassic 153-145 million years ago. In the documentary, Allosaurus were featured in the latter half of the Late Jurassic segment as 'the most advanced flesh eater of its day'.


Allosaurus hunting a young Apatosaurus

In When Dinosaurs Roamed America Edit

Late Jurassic segment Edit

Allosaurus first appears at the beginning of the wet season. A hungry Allosaurus tries to attack a young Apatosaurus but the mom scares him off with her whip-like tail. The Allosaurus then attacks and kills a Ceratosaurus who was chasing two Dryosaurus. Then, while walking away to avoid the dry season, an Apatosaurus breaks its leg and falls down a 20 foot drop, mortally wounding it. Three Allosaurus attack it and eat it alive.

Errors Edit

  • Allosaurus is portrayed as 'the most advanced flesh eater of its day', implying it was the top predator, however there were multiple other carnivores that were even larger than it, such as Saurophaganax (if it is a distinct genus), and Torvosaurus.
  • Allosaurus' hands couldn't pronate without breaking them.
  • Allosaurus would've been smaller, at 32 feet long instead of 43 feet. It's possible the Allosaurus in the documentary could be representative of the much larger genus of Allosaurid, Saurophaganax, which was similar in size to the Allosaurus in the documentary. However there are controversial claims of Allosaurus reaching 40 feet.


  • Recently, some study had been done on the skull of the Allosaurus Big Al" reveal two extraordinary things about this predator:
    • It had a weak bite: Allosaurus had weak jaw muscles. It had a bite force of only 200 kilograms, which is the same as a leopard's. So it was no bone crusher, like the T. rex.
    • It had a strong skull: Despite its weak bite, Allosaurus' skull was extremely good at transmitting force along its length. With more openings and much lighter than T. rex's head, it was structured to carry tremendous levels of stress, as much as 6 tons!
    • This shows that Allosaurus would have used its head like a hatchet, using its strong neck muscles to ram its teeth from its upper jaw into the body of its prey. This method of attack when shown isn't pretty, nor clinical, but it's ruthlessly efficient.

Community content is available under CC-BY-SA unless otherwise noted.