Allosaurus
What do you already know about this theropod dinosaur?
Can you say...
al - uh - saw - rus
The name Allosaurus means ‘different lizard’.
Allosaurus lived in the late Jurassic Period and would have been the biggest theropod dinosaur living then. It would have been between about 8 and a half metres to 12 metres in length from its head to its tail, and would have stood at about 4 and a half metres tall.Â
Allosaurs walked on its two strong back legs. It is thought they could run quite fast, as its body was balanced out by its tail. It had quite short arms, but weren’t as short as T Rex’s though, who lived later on in the Cretaceous Period. Unlike T Rex, Allosaurus could have used its powerful arms to help attack its prey, grabbing them and holding on to them. It had three long sharp hook shaped claws on its arms and feet, which would have also helped too! These claws could be around 20 centimetres long.
Allosaurus had a long head, which was about 90 centimetres long. It had bony crests above its eyes and nose. It would have had lots of very sharp serrated teeth that could be up to 10 centimetres long. If it lost a tooth, which they did regularly (we know this as lots have been found), it could just grow a new one. They had perfect teeth for ripping through meat, they would have been a bit like a steak knife.
Allosaurus was a meat eating dinosaur so would have attacked other dinosaurs which lived at the same time. It may have hunted in packs and that would have meant they could have teamed up to attack massive sauropod dinosaurs like Diplodocus. It also would have attacked smaller dinosaurs too which lived at the same time, such as Stegosaurus. Allosaurus would have been the top of the food chain so no other dinosaurs would have hunted it, it was far too big!
Fossils of Allosaurs have been found in what is now America, as well as places such as Portugal, Germany and Tanzania. A lot of its fossils have been found in America so we know quite a lot about this theropod dinosaur. The reason Allosaurs was named ‘different lizard’ was because when palaeontologists first discovered its bones, the spine was a very different shape to the other dinosaurs that had been discovered at the time.
One Allosaurus fossil found was named Big Al. It was discovered in America in 1991 and was about 95% complete, meaning only tiny bits of it were missing. All the bones were also found in pretty much the original positions which was amazing. This meant they could find out a lot of important information about it. Although being called Big Al, it wasn’t that big and thought to have been about 15 years old when it died. Only a few years later Big Al Two was discovered in the same place and was even more complete.
We know Allosaurs definitely hunted Stegosaurus because a Stegosaurus fossil has been found with an Allosaurs bite mark on its neck plate. An Allosaurus fossil has also been found with damage from a Stegosaurs trying to protect itself...amazing!
What we've learnt...
The name Allosaurus means ‘different lizard’.
People pronounce its name al – uh – saw – rus
Allosaurus lived in the late Jurassic Period at the same time as Diplodocus and Stegosaurus.
Allosaurus was the biggest, scariest theropod living at the time.
Allosaurus had stronger, bigger arms arms than T Rex, but in general was smaller than the Cretaceous living theropod.
We know lots about Allosaurs through their fossils, including Big Al.
Test your knowledge...
Allosaurus Quiz
If you click the correct answer the box will turn green. If its the wrong answer it will turn red and then show you what the correct answer was. Make sure you read/listen to the questions carefully!
#1. What was the almost complete Allosaurus found called?
#2. Could Allosaurs use its arms to help attack its prey?
#3. Was Allosaurs the biggest theropod living at the time?
#4. What type of dinosaur was Allosaurs?
#5. When did Allosaurs live?
Results
I really hope you have enjoyed learning all about Allosaurus, with me Flash!
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The photos on this page are of dinosaur models and computer generated images. They are used to give you an idea of what the dinosaurs would have looked like, but I can’t guarantee they are 100% accurate!
Creative Commons Images, used with thanks…
Allosaurus Skeleton by Nekarius – CC BY-SA 3.0
Allosaurus and Stegosaurus by Chobist – CC BY 2.0
Unsplash Image, used with thanks…
Dinosaur on a field of grass by David Valentine
Other photos and illustrations on this page are Whizzbots or Public Domain Images.