An Ultimate Guide to Saurophaganax: King of Lizard Eaters

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Name Meaning“Lord of Lizard-eaters”Height4 meters (13.1 ft.)
Pronunciationsore-oh-fag-ah-naksLength10.5 to 13. 1 meters (34 to 43 ft.)
EraMesozoicLate JurassicWeight2.7 to 3.8 metric tons (3 to 4.2 short tons)
ClassificationDinosauria,‭ ‬Saurischia,‭ & TheropodaLocationNorth America (United States)

Saurophaganax Pictures

3D illustration of Saurophaganax
3D illustration of Saurophaganax | Sergey Krasovskiy via GettyImages

The Saurophaganax

Gage Beasley Prehistoric's Saurophaganax Concept
Gage Beasley Prehistoric’s Saurophaganax Concept

Saurophaganax is a genus from the Allosauridae dinosaur family. 

First discovered in the Morrison Formation in the central United States, this genus dates back to the Late Jurassic period, to the Kimmeridgian age around 151 million years ago. 

Saurophaganax was an extremely large theropod, sharing many similar traits to other carnivorous dinosaurs

With today there is still little fossil evidence discovered of Saurophaganax, and there is still much to learn about this ancient giant.

Though difficult, scientists have uncovered many of the mysteries about the Saurophaganax, even with the little fossil evidence they left behind. 

Saurophaganax's size and ferocity has earned the moniker of "King of Lizard Eaters"
Saurophaganax’s size and ferocity has earned the moniker of “King of Lizard Eaters” | Mario Lanzas via Wikipedia CC BY-SA 4.0

The Allosauridae family contains some of the most successful land predators in Earth’s history, and these giants ruled the prehistoric environments they lived in. 

Other Allosaurids have been essential in learning more about Saurophaganax the “King of Lizard Eaters”.

The first Saurophaganax fossils have been heavily studied since their discovery in 1931. 

Here you will find everything paleontologists have managed to learn about Saurophaganax, including things like what they eat, how they could have looked, and what role this giant predator played in their ecosystem. 

While there has been a lot has been learned about Saurophaganax, like with all dinosaurs what is known may change as new discoveries, and studies occur. 

Gage Beasley's Prehistoric Shirt Collection
Gage Beasley’s Prehistoric Shirt Collection

Physical Characteristics

Saurophaganax is the largest carnivorous dinosaur found in the Morrison Formation and is also one of the largest known Allosaurids. 

Like other theropods, Saurophaganax stood on two legs and had large heads and small arms. 

They stood at a height of around 4 meters (13 feet) tall and had an estimated length between 10.5 to 13.1 meters (34 to 43 feet).

Not only is Saurophaganax one of the largest, but was also among the heaviest in the Allosauridae family, having an estimated weight between 2.7 to 3.8 metric tons (6,000 to 9,900 lbs).

Gage Beasley Prehistoric's Saurophaganax Concept
Gage Beasley Prehistoric’s Saurophaganax Size Comparison Chart

The build of this dinosaur was designed to allow them to be fierce predators, and they had a strong, muscular build, with sharp teeth. 

Only partial remains of Saurophaganax have been discovered, which is not uncommon for large dinosaurs. 

The size of Saurophaganax fossils is what distinguished this genus from other Allosaurids, even though many of their fossils looked similar to other dinosaurs. 

Large fossils found of Saurophaganax including claws that measured 26.67 cm (10.5 in.), a large femur bone that had a length of 111.76 cm. (44 in.), and teeth that were up to 12 cm (4.72) large.

The few fossils found of this dinosaur, and other similar dinosaurs are how paleontologists have managed to figure out how this dinosaur looked. 

Habitat and Distribution

The fossils of Saurophaganax have been found only in the United States, in places like Oklahoma, and Texas. 

Saurophaganax lived in North America during the late Jurassic period, and the formation of this dinosaur was found dates from the Kimmeridgian to the Tithonian ages.

The Morrison Formation is where Saurophaganax was discovered, and the radiometric dating and analysis of the sediment have helped paleontologists learn about habitats, and the environment this dinosaur lived in.

The Late Jurassic period had a semi-arid environment, along with periods of wet, and humid seasons. 

Along with large semi-arid environments that were present in the late Jurassic period, North America also had large wetlands and river environments. 

Some of the fossilized plants found where Saurophaganax live include ferns, cattails, fungi, mosses, and cycads. 

North America looked very different during the Jurassic period and was one large landmass before getting split by the Western Interior Seaway during the Cretaceous period

Behavior and Diet

Saurophaganax was a carnivore that was an apex predator in its environment and was able to feed on any dinosaur they came across. 

This dinosaur would feed on large sauropods they lived with like Diplodocus, Apatosaurus, and Amphicoelias

A Saurophaganax attacking a sauropod
A Saurophaganax attacking a sauropod | Image via SurviveTheArk

The size of Saurophaganax would have made them the dominant dinosaur in North America during the Late Jurassic, but these dinosaurs could have also been scavengers. 

Being so large Saurophaganax would have been slower than smaller dinosaurs and that could have made it difficult for them to hunt.

One theory about how these dinosaurs ate is that they were scavengers, using their size to bully other predators and steal their freshly caught meals. 

Saurophaganax could be compared to modern hunters like lions, who would hunt for their own food, but also would go out of their way to steal food from smaller hunters like hyenas. 

The name Saurophaganax translates to “lord of lizard-eaters” since this dinosaur was the largest predator of its time, and preyed on the other dinosaurs, even predators like large theropods. 

Allosaurids were the top predator of the Jurassic period, and the Saurophaganax was the king of them all. 

Saurophaganax main prey was likely herbivores, but their size made any animal they came across a potential meal. 

Saurophaganax was a danger to any animal it encountered
Saurophaganax was a danger to any animal it encountered | MoNaS288 via Dinosaur Wiki

Life Cycle

The little fossil evidence left behind from Saurophaganax makes it difficult for paleontologists to understand the lifecycle of this dinosaur. 

Since this dinosaur is very similar to the Allosaurus it is likely they had similar life cycles. 

Allosaurus had a lifespan estimated to be around 28 years and reached full maturity at around 15 years old. 

All dinosaurs, including Saurophaganax, start out in eggs, and are likely guarded by their mother until they hatch, and are ready to fend for themselves. 

Large dinosaurs like Saurophaganax did not live, or hunt in groups, and had a solitary life as an adult. 

Saurophaganax led a solitary lifestyle
Saurophaganax led a solitary lifestyle | Image via SurviveTheArk

In the future, there may be more information discovered about the life cycle of Saurophaganax, but fossils from larger dinosaurs are typically rare to find. 

Similar species like the Allosaurus have been essential in learning about Saurophaganax, since fossils from those dinosaurs have been much more abundant.

Evolution and History

In the 1930s, in Oklahoma, Saurophaganax was discovered and was found in the Morrison Formation.

Reconstructed Saurophaganax skeleton at the Sam Noble Oklahoma Museum of Natural History
Reconstructed Saurophaganax skeleton at the Sam Noble Oklahoma Museum of Natural History | Chris Dodds via Wikipedia CC BY-SA 2.0

This dinosaur was discovered by John Willis Stovall, and he pulled up the fossil’s remains near the town of Kenton, in Cimarron County.

Originally the name Saurophagus maxiumus was given to the dinosaur remains, but it was later changed since Saurophagus was already given to a type of bird. 

In 1995 a new genus of Saurophaganax was created by Daniel Chure, and today the only species in this genus is Saurophaganax maximus.

While today Saurophaganax is its own genus, it has been debated whether the fossils found of this dinosaur were just larger bones of the Allosaurus, which is a very similar dinosaur. 

Studies done as recently as 2004, and 2012 have accepted Saurophaganax as its own genus, but further discoveries may help clear up the confusion between these two dinosaurs. 

Saurophaganax fossils have been extremely rare to find, and this is mainly due to their size. 

Large animals have a more difficult time being fossilized since when they die it is rare for their body to become completely covered, and remain untouched.

A drawer of Saurophaganax vertebrae, Oklahoma Museum of Natural History
A drawer of Saurophaganax vertebrae, Oklahoma Museum of Natural History | Carpenter, Kenneth via Wikipedia CC BY-SA 4.0

The size and rarity of Saurophaganax fossils discovered compared to other dinosaurs like the Allosaurus suggested these dinosaurs did not have large populations in their environments. 

Interactions with Other Species

In its prehistoric ecosystem Saurophaganax was an apex predator and ruled over the other dinosaurs they coexisted with. 

This species was one of the largest land carnivores in North America during the Jurassic period, and could even eat smaller theropods they came across. 

In the formation where Saurophaganax was discovered there have been several other dinosaurs found that date to the same period, and coexisted with this dinosaur. 

Some of the other dinosaurs that lived in the Jurassic period in North America alongside Saurophaganax include:

  • Dryosaurus
  • Nanosaurus
  • Ornitholestes
  • Marshosaurus
  • Stokesosaurus
  • Camptosaurus
A Saurophaganax attacking a Stegosaurus
A Saurophaganax attacking a Stegosaurus | Arthur Dorety via GettyImages

Saurophaganax prey was made up of mostly herbivorous dinosaurs, but they had enough strength to take out other carnivores.

Despite being slower than most other dinosaurs, Saurphaganax was still quick enough to catch up to most plant eaters, and they likely only went after smaller carnivores that were young, or injured.

Cultural Significance

In Oklahoma, Saurophaganax is considered the state fossil, and it was named that in 2000 because of its enormous size and its dominant rule of Oklahoma during the Jurassic period.

On the right is a Saurophaganax skeleton while on the right is a Apatosaurus skeleton
On the right is a Saurophaganax skeleton while on the right is a Apatosaurus skeleton | Meghunter99 via Fossil Wiki

Allosaruids were one of the most common predators in North America, Africa, and Europe during the Jurassic period, and Saurophaganax was one of the most uncommon of its time.

Fossils from this dinosaur have been helpful in understanding the ecosystem of the Jurassic period, as Saurophaganax were a keystone species that had a large effect on the habitats they lived in.

Saurophaganax fossils are extremely rare, compared to other Allosaurids, and theropods that lived in North America. 

The appearance of Saurophaganax is known due to other similar dinosaurs, and there has been some confusion about whether this genus is just a synonym for the Allosaurus

The size and predatory fierceness of Saurophaganax are why many have come to love this prehistoric giant. 

Depictions of this dinosaur in media and games may be inaccurate, but with time and more studies, more will be learned about this ancient dinosaur. 

A Saurophaganax's as seen in Jurassic World: The Game
A Saurophaganax’s as seen in Jurassic World: The Game | Palaeontologica via Jurassic Park Fanon


Compared to other similar dinosaurs like the Allosaurus, Saurophaganax is one genus that still has a lot of mystery about them, mainly due to the little fossil evidence this species left behind.

Saurophaganax was one of the largest dinosaurs that lived in North America and fiercely ruled during the Jurassic period. 

Dinosaurs are one of many of Earth’s mysteries, and it is amazing how paleontologists piece together animals that lived millions of years ago. 

Studies and new fossils will help us learn more about Saurophaganax in the future, but the size of this dinosaur is why discoveries have been uncommon. 

Saurophaganax is one of the many theropods that lived in North America and showcased how amazing prehistoric animals evolved before going extinct. 


What was the bite force of Saurophaganax?

Despite being extinct, the bite force of some dinosaurs can be discovered using their fossils, and computer modeling. 

The bite force of Saurophaganax is estimated at 2,721 kgs (6,000 lbs) of pressure. 

Their strong bites, large teeth, and size of Saurophaganax are why these dinosaurs were apex predators, and some of the most dominant land carnivores to exist. 

When did Saurophaganax go extinct?

Saurophaganax fossils date to the late Jurassic period, and it is believed these dinosaurs went extinct during the Cretaceous period, along with other Allosaurids. 

While the timeline and cause of the extinction of these dinosaurs are relatively a mystery, some theories as to what caused their demise include drought, a lack of food, and other dinosaurs evolving to out-compete them. 

The extinction of Saurophaganax allowed for other dinosaurs like Tyranosaurids to become dominant in the Cretaceous period. 

Did Saurophaganax have feathers?

Due to the little fossil evidence from Sauorphaganax, it is still debated whether this dinosaur had feathers

What is known is that these dinosaurs had scaly skin, but it is likely these dinosaurs, along with other types of Allosaurids, could have had feathers when young. 

The discovery of more fossils and research into similar species may solve the mystery of whether Saurophaganx had feathers, but it is currently believed they did not. 


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