Stegosaurus vs Allosaurus: Who Would Win in a Fight?

Written by Kyle Glatz
Published: May 11, 2022
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Although we know that dinosaurs fought and fed on one another, scientists don’t have a trove of fossil evidence that shows exactly how it happened. However, they do have a few very well-preserved pieces from a Stegosaurus vs Allosaurus fight. Who was the winner, and how did they manage? We’re going to break down this fight between the two massive reptiles and use the available data to show how it could have played out.

Even if you think you know the winner of this fight, you’ll want to see what the fossils records revealed about this matchup!

Comparing a Stegosaurus and an Allosaurus

Stegosaurus has the size advantage.
SizeWeight: 11,000lbs-15,400lbs
Height: 7ft-9ft at the hip, closer to 14ft tall overall
Length: 20ft-30ft
Weight: 3000-4400lbs
Height: 16.5ft
Length: 38ft-43ft
Speed and Movement Type– 3.5-4.3 mph– 21-35 mph  
– Bipedal strides
Defenses– Had up to 22 dermal plates that rose from their back which may have been used for defense
– Strong, thick bones
– Large size would scare some predators away
– High running speed
– Large size  
Offensive Capabilities– Would swing its tail and slam its thagomizer (tail spikes) into predators
–  Tail spikes measured between 2ft and 3ft
6,125lbf bite power
-28-39 teeth that were 2-4-inches long
-D-shaped teeth with serrated edges
– Three sharp, curved claws at the end of each limb measuring upwards of 7 inches
Predatory Behavior– Stegosaurus was an herbivore, so it didn’t prey on anything– Was likely an ambush predator that would attack the throat of its prey
– May have jumped on enemies to bite and claw at the same time
– May have hunted in packs

What Are Key Differences Between a Stegosaurus and an Allosaurus?

The greatest differences between a Stegosaurus and an Allosaurus are their morphology and size. The Allosaurus was a bipedal theropod standing 16.5ft tall and weighing up to 4,400lbs with a large head, long tail, and relatively short arms, and the Stegosaurus was a 7ft tall and potentially 15,400lb dinosaur with a small head, rows of large dermal plates running down its back, and a group of four large spikes on its tail that are sometimes called a thagomizer.

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These are significant differences between the two dinosaurs, and they’ll help us figure out which one would win a battle. Yet, we need to examine other factors to make sure we determine which dinosaur is the clear winner.

What Are the Key Factors in a Fight Between a Stegosaurus and an Allosaurus?

Stegosaurus in Forest

Stegosaurus was an herbivore, but it was not helpless.


Every fight in the wild comes down to a handful of important factors. In this case, we have to look at things like size, speed, and how the animals fight against others. We’re going to review five different aspects of these dinosaurs and show you which animal has the advantage and the best chance of winning this battle.

Stegosaurus vs Allosaurus: Size

A Stegosaurus is much heavier than an Allosaurus, weighing up to 15,400lbs compared to the theropod’s maximum weight of 4,400lbs. However, the Allosaurus was much taller, perhaps 16.5ft in height and up to 43 ft in length. Stegosaurus could only measure about 14ft tall and 30ft long.

In this case, Stegosaurus had the advantage because it’s a heavier, more muscular creature with a smaller profile.

Stegosaurus vs Allosaurus: Speed and Movement

Allosaurus was much faster than Stegosaurus. Using bipedal strides, Allosaurus could reach speeds of 21-35 mph. However, Stegosaurus could only move at speeds of 3.5 mph to 4.3 mph. With that in mind, the Allosaurus would have no trouble chasing down the Stegosaurus. However, it may have come to regret that decision if it didn’t mind the thagomizer.  

Allosaurus had the advantage in speed.

Stegosaurus vs Allosaurus: Defenses

The Stegosaurus was a fairly large dinosaur, but it wasn’t among the largest dinosaurs. Nevertheless, its skin had osteoderms protecting it from some puncture attacks, and the dinosaur had large dermal plates that could prevent some attacks from above. The dinosaur’s large size as an adult probably offered the most protection against attacks from smaller dinosaurs.

The Allosaurus was tall and long, but it wasn’t thickly built. Instead, it relied on its speed and overall size to keep it out of trouble.

Stegosaurus had the defensive advantage.

Stegosaurus vs Allosaurus: Offensive Capabilities

The Stegosaurus was not known for being an offensive powerhouse, but it could fend off some trouble. This dinosaur had a long tail that had a thagomizer on the end. This series of four spikes could measure between 2ft and 3ft long. When they connected with a predator, these spikes could dig in and do serious damage.

Allosaurus was loaded for attack when it came to attacking prey. They had a somewhat strong bite, up to 39 teeth that measure 2in-4in long. Moreover, these dinosaurs had three sharp claws on their hands and feet, measuring up to 7 inches at their maximum. They could bite and tear a creature to death while also digging in with their claws!

Allosaurus had the offensive advantage.

Stegosaurus vs Allosaurus: Predatory Behavior

The Allosaurus may have been a pack-hunting carnivorous dinosaur, biting and tearing larger prey with others. However, more data is needed to say this with certainty. If that was the case, they would wear down prey before finishing them. Nevertheless, Allosaurus was a powerful hunter that probably jumped on enemies with a bite and tore away chunks of flesh with head movement while simultaneously slashing them with all their claws.

Stegosaurus had no predatory behavior since it was an herbivore. Yet, it was anything but helpless.

Who Would Win in a Fight Between a Stegosaurus and an Allosaurus?


Allosaurus was a tough dinosaur that used deadly attacks and speed to overcome prey.


An Allosaurus would win a fight against a Stegosaurus. The truth is that the Allosaurus would most likely strike quickly at the Stegosaurus, either biting its head, brutally slashing it, or using a combination of the attacks to kill the sauropod.

Allosaurus was a lot lighter than Stegosaurus. Yet, it’s also faster, smarter, and more adept at fighting. The Allosaurus would need to do a lot to kill the Stegosaurus, slashing and biting several times to finish it off.

However, the Allosaurus winning the fight is not a foregone conclusion. A fossilized Allosaurus showed signs that it had been struck and deeply penetrated by the spike of what could only be a Stegosaurus. That Allosaurus died after the attack due to the unfortunate location of the strike in the Allosaurus’ vertebrae.

That’s not a typical case, though. In most fights, the Allosaurus, either alone or in a pack, would kill the Stegosaurus.

The photo featured at the top of this post is © Warpaint/

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About the Author

Kyle Glatz is a writer at A-Z-Animals where his primary focus is on geography and mammals. Kyle has been writing for researching and writing about animals and numerous other topics for 10 years, and he holds a Bachelor's Degree in English and Education from Rowan University. A resident of New Jersey, Kyle enjoys reading, writing, and playing video games.

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