Amazingly, Allosaurus fossils had been preserved for the last 150 million years in the Morrison formation. For palaeontologists, it is a Jurassic playground.

Allosaurus had knife-like teeth that were shed and replaced over its lifetime. The teeth were up to four inches in length and became shorter, more curved and narrow towards the back of the mouth. These teeth would have been excellent at ripping off pieces of flesh.

Allosaurus could most likely have taken a swim - imagine this gigantic beast coming toward you in the water.

Some scientists suspect Allosaurus was a solitary hunter and would have held large territories, much like a tiger, but this is difficult to prove using the fossil record.

Allosaurus had a lifespan of about 25 years. This was about average for a dinosaur of its size, rate of growth and metabolism. By comparison, large dinosaurs such as Brachiosaurus would have lived for over 50 years!

The forearm of Allosaurus was less than 35% the length of its hind limb. Scientists are uncertain why these dinosaurs, as well other bipedal meat eaters, had such short arms.

Overall, dinosaurs were not the brainiest bunch. And though Allosaurus was only as smart as an ostrich, it was a total brainiac compared to dinosaurs like the plate-backed stegosaurs, which had some of the tiniest brains among dinosaurs.



"Different Lizard"


Allosaurus was a large bipedal dinosaur with a huge skull balanced by a long and heavy tail.  Being a large and powerful meat eater with formidable teeth and a savage bite, Allosaurus would have been top dog in its Jurassic ecosystem. It would have been quick enough to outrun its very slow prey. 



Allosaurus lived during the Late Jurassic.

Extinct for about: 00,000,000,000 Days00 Hours00 Min00 Sec

How old are you?
00,00,00.00 of your lifetimes have passed since their extinction.

They Call it Home

Allosaurus has been found primarily in North America's Morrison Formation, with a few fossils also known from Portugal. The Morrison Formation itself is a long stretch of ancient rock running from Montana, all the way to New Mexico. The rock formation allows us to step back in time to see a once verdant landscape of rivers, lakes, and vast plains - a perfect setting for such an awesome ecosystem.





Rivers / Lakes

Rivers / Lakes




  • North America (Morrison Formation)
  • Montana
  • Portugal

What We Heard About Their Hearing

Human Ear

Allosaurus had crocodile ears. It would have had poor hearing, only being able to hear low frequency sounds.


What Big Teeth You Have

Dinosaur Tooth

Allosaurus had backward facing teeth, which meant with each struggle, its hapless victim would be pushed further down the dinosaur's huge throat.


Nose Knowledge

Human Nose

Allosaurus had a well-developed sense of smell, useful for sniffing out its prey.


The Poop Scoop

Dinosaur Poop

Allosaurus droppings have been found to be 1.52 m (~5 ft) in length and 10.2 cm (4 in) thick. That's a daunting amount of dung!


The Most Fantastic Find

IIn 1991, near Shell in Wyoming, a Swiss team led by Kirby Siber unearthed the best-preserved fossil Allosaurus ever found. It was an almost complete skeleton dubbed "Big Al". Big Al had unfortunately died very young with massive injuries. As a consequence, he intrigued the media with his story and featured in the BBC Walking With Dinosaurs special The Ballad of Big Al. Later on, the same team discovered a similar Allosaurus fossil which was even better preserved than Big Al. The fossil was named "Big Al 2".

From The Expert

It may seem strange that Allosaurus has been found in both the western United States and Portugal, areas that are over 7000 kilometres apart today. During the Jurassic Period, however, these areas were much closer together. Even so, it's not like Colorado and Portugal were joined together during this time, soAllosaurus must have had a very widespread distribution.


Sizing it Up


Compare to:

5m / 16.4ft

At this size, Allsaurus was still smaller than Spinosaurus

1 human
1 human
5 m / 16.4 ft


Number of people head-to-toe to reach the top of Allosaurus. (average human height 1.76 m / 5.7 ft)

Compare to:

12m / 39.36ft

Even at the length Allosaurus was shorter than T.rex.

1 human
1 human
12 m / 39.36 ft


Number of people side by side touching finger tips to match this length (average arm span 1.7 m / 5.58 ft ).

Compare to:

1.4tonnes / 1.57short tons

Allosaurus was as heavy as a forklift.

allosaurus weight

Number of people weighing 70.31 kg / 155 lbs needed to match the weight of Allosaurus.


Dino On The Go!

The top speed of Allosaurus

33.8kph / 21.00mph

  • Horse 52 kph / 32.3 mph
  • Allosaurus33.8 kph / 21.00 mph
  • Cheetah 120.7 kph / 75 mph

22.5kph / 14mph

The average human sprint speed.


Family Album

Family Album

One Allosaurus cousin would have been T.rex. Both were members of the theropod group, which included all carnivorous, bipedal dinosaurs. The theropod's descendents are modern day birds. 



Allosaurus Vision

Allosaurus had its eyes in front of its head facing forward so that it would have been better able to work out distance and time to attack.

Allosaurus Vision.

Human Vision

The human field of view is roughly 180 degrees.

Human Field of View

The Skinny On Their Skin


The skin of Allosaurus would have been smooth and leathery.


What's In The Nest?

Allosaurus Egg

We know Allosaurus laid eggs. However we don't quite know what they would have looked like.



allosaurus brain size

Allosaurus had an oval-shaped brain, about the size of a small loaf of bread, though probably not as tasty... unless you were another dinosaur.


Quite The Bite

The estimated maximum bite force of Allosauruswould be less than alligators and leopards.

Allosaurus Bite
  • Alligator
  • Lion
  • Leopard
  • Allosaurus

    Bite Force (N)


    Average force of human bite, measured at molars.


    Good Eatin'

    Plant Icon

    Allosaurus was an active predator of large animals such as the long-necked Diplodocus and the plate-backed Stegosaurus. These were all found together at the same time in the same habitat and location.


    Parental Guidance

    Allosaurus Parent and Child

    Allosaurus could well have been a kind and considerate mother. Scientist Robert Bakker, known for his outlandish theories, has described a find of Allosaurus teeth from both adult and juveniles alongside chewed bones of large prey. He cites this as evidence that the adults would bring back food to their lairs for their young. As often happens, there is no consensus among scientists, so it remains just one possible explanation.


    True Colours

    Color Wheel

    We don't quite know, so traditional dinosaur illustrations are our best guide!