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10+ Largest Prehistoric Reptiles (Not Dinosaurs and Pterosaurs)

Without a doubt, dinosaurs are the most famous giants that ever roamed the Earth. However, they are far from the only known reptiles that reached incredible sizes. But not many people know about those giants.

Now you will find out the largest prehistoric reptiles besides dinosaurs and pterosaurs


50 thousand years ago, the vast and untamed landscape of Australia was ruled by some of the most formidable reptiles such as a six-meter land crocodile named Quinkana and the Komodo dragon, the largest lizard today.  

But there was one among these great beasts that was the largest, a lizard of immense size and formidable power. This was the Megalania, a fearsome creature that shared a similar bone structure and posture with its smaller cousin, the Komodo dragon.

Despite their similarities, however, there was nothing small or insignificant about the Megalania. While the Komodo dragon measured up to a mere 3 m in length, the Megalania’s maximum length could be 7 m. And when it came to weight, the Megalania was no lightweight either, tipping the scales at 1,940 kg.

But while the Megalania is recognized as the largest land lizard ever, Barinasuchus holds the title for the largest land reptile known since the extinction of dinosaurs.


12 million years ago, South America was home to a true behemoth, the largest land predator since the extinction of the dinosaurs. Its territory spanned from Venezuela to Argentina, a vast swath of land that it ruled with an iron grip. This was the Barinasuchus, a fearsome predator that was a relative of crocodiles.

Compared to the modern-day crocodile, Barinasuchus was notably bigger, given that most crocodile species nowadays reach lengths of 2 to 5 meters. Barinasuchus was a true behemoth. Its maximum length could be an incredible 7.5 m, and it could weigh 1,720 kilograms. Even allowing for a 50% margin of error, it was still larger than any terrestrial Cenozoic predatory mammal. But Barinasuchus was not the largest relative of crocodilians that inhabited South America.


222 million years ago in South and North America, a fascinating family of animals thrived. These animals were unique, as they were bipedal plant-eaters. Almost all of them were under three meters in length, but Sillosuchus, which was exclusive to South America, was the exception to this size limitation.

It could reach lengths of up 10 m, making it the largest known bipedal reptile except for the dinosaurs.

Despite the immense size of the prehistoric land reptiles, the oceans and rivers of the world were also the habitat of colossal reptiles.


112 million years ago, in the rivers of Africa and South America, a powerful monster prowled the waters. It is known as the Sarcosuchus, and despite its external resemblance to modern-day crocodiles, it wasn’t in fact a direct relative of these animals.

Although the Sarcosuchus may have shared certain physical traits with modern-day crocodiles, such as its long snout and powerful jaws, its sheer size set it apart as a truly unique form of life.

With a maximum length that could reach up to 9.5 m, and a weight of over 4.3 metric tons, the Sarcosuchus is one of the largest crocodilomorphs ever known to exist. The larger distant relative of modern crocodiles is called Stomatosuchus.


94 million years ago, this unusual giant roamed the waterways and wetlands of what is now Egypt.

With a skull that reached up to 2 m in length, this creature may have measured up to 10 m in length.

The most unusual part of its body was its skull, it is considered to be the largest among giant crocodiles. The skull was flattened, and it had lid-like jaws that were studded with small conical teeth. The lower jaw of the Stomatosuchus may have been toothless and could have supported a pelican-like throat sac. This sac could have been used to scoop up fish, similar to how modern pelicans hunt. And the conical teeth prevented prey from escaping.

With its unique skull and size, Stomatosuchus stands out as one of the most extraordinary reptiles to have ever lived on Earth. But nature created even larger river monsters.


13 million years ago, South America was home to one of the largest gavials in history, if not the largest, the Gryposuchus. Its habitat spanned across Venezuela to Argentina. It was a very successful predator.

Similar to modern gavials, Gryposuchus had telescopic eyes that provided an enhanced field of view for observing prey, such as fish and crustaceans, and a slender snout that was adapted for catching fish. 

Gryposuchus was not merely a larger version of the modern gavials, it was a gargantuan beast that was almost twice their size. With an incredible length that could reach up to 10.15 m and a weight of around 1,745 kg, this colossus of the prehistoric era was a truly imposing figure in the landscape of its time.


But in the time of the dinosaurs there was a crocodile much larger than the Gryposuchus. It’s called Deinosuchus. This monstrous alligatoroid crocodilian inhabited the coastal regions of eastern North America approximately 73 million years ago. And it was a dominant force on both sides of the Western Inland Seaway, where it ruled the swamps and marshes with its immense size and power.

No other theropod could match the Deinosuchus in size. It reached an average length of 10 m and weighed 5 metric tons. However, certain individuals belonging to the Deinosuchus riograndensis species grew even more gigantic, with several reaching an astounding 12 m in length and weighing 8.5 metric tons.

While not the biggest crocodile of all time, this particular one holds the record for being the largest known species to have lived during the dinosaur era.


The title of the biggest crocodile of all time belongs to a beast known as Purussaurus, whichinhabited the rivers of South America during the Miocene Epoch.

With its wide, flattened snout and massive jaws, Purussaurus was the ultimate predator, designed for taking down even the largest prey of its time. And it was enormous, with a maximum length of 12.5 m and weighing 8.4 tons.

Despite its impressive size, Purussaurus coexisted with another giant crocodile, the Gryposuchus. Together, these predators ruled the rives of South America. Gryposuchus had a long, narrow snout adapted for catching fish and crustaceans, while Purussaurus had a broader snout and was better adapted for hunting larger and tough prey such as turtles, mammals, and other reptiles. This allowed both species to coexist without directly competing for the same resources.

But following the extinction of dinosaurs, there were reptiles bigger than these crocodiles.


As impressive as Purussaurus and Gryposuchus were, they were not the only giants that hunted in the rivers of South America.

In the wake of the mass extinction of the dinosaurs, 58 million years ago, global temperatures were 10 degrees Celsius higher than what they are today, creating a perfect habitat for the relative of the modern boa, the Titanoboa. This massive fish-eating snake lived in Colombia and is known for its incredible size.

The Titanoboa was not just big, it was a colossal serpent, stretching up to an astounding 12.8 m in length and weighing 1,135 kg, making it the absolute behemoth of all snakes ever found.

However, as the temperatures cooled, the heat-loving, cold-blooded Titanoboa struggled to adapt.  

Now let’s take a deep dive into the depths to discover the colossal creatures that once roamed the ancient seas.


74 million years ago, in the Western Inland Sea Passage, there existed a creature so massive and unique that no similar nowdays animal can be compared to it in terms of size. This creature was none other than Archelon – a true leviathan of the ancient seas and the largest turtle known to have existed.

Archelon’s incredible size was apparent in every aspect of its body, from its massive flippers to its formidable skull. Its flippers, ranging from 490 to 610 cm in span, were a crucial tool for efficient movement in the open ocean.

The leathery shell with a spongy structure, much like that of the modern leatherback turtle, the largest turtle today, was an adaptation that helped reduce weight and increase efficiency.

With a colossal body weight that could crush scales at 3.2 metric tons and length that stretched 4.6 meters from head to tail, Archelon was undeniably a true titan among predators, reigning supreme in the ancient Western Inland Sea Passage with an insatiable appetite for prey. Its powerful jaws and hooked beak were capable of crushing, allowing it to feast on a variety of prey, including crustaceans, mollusks, and even sponges.

Pliosaurus funkei

Another colossal beast existed 147 million years ago. This magnificent creature is known as Pliosaurus, a name derived from the ancient Greek words “pleion,” meaning “more,” and “sauros,” meaning “lizard.” Pliosaurus was not just the apex predator of its time, it is also the largest known pliosaur to ever exist.

This beast was a colossal creature, with a length that can reach an incredible 12 m and a weight that can go up to an impressive 11 metric tons.

Its front limbs alone measured 3 meters in length and were powerful tools for hunting and navigating the ocean depths. Its hind limbs were used to accelerate when needed. The most striking feature of Pliosaurus was its skull, which measured 2.5 m in length, housing teeth that reached up to 30 cm. This giant predator was truly a terror of the deep, preying on almost anything that crossed its path. With its size and strength, Pliosaurus was the undisputed top predator of its time.


But 66 million years ago, the Atlantic Ocean and its neighboring sea lanes were home to an even more fearsome and bigger predator – the mosasaur.

This beast was close relative of lizards and snakes, but structurally similar to other large marine vertebrates like ichthyosaurs, marine crocodilomorphs, and archaeocetes whales.

At 13 m in length and weighing 5.5 metric tons, it was a true leviathan that ruled the seas with its sheer size and power. Its sleek, muscular body was built for speed and agility, allowing it to chase down its prey with ease. With its sharp teeth and powerful jaws, the mosasaur was a top predator, ruling the waters with an iron grip.  

Its dominion was about to end shortly, as the catastrophic asteroid collision that eradicated the dinosaurs and other massive species on the planet 66 million years ago was right around the corner. But the largest known reptile existed long before this event.


205 million years ago, the vast expanses of the world’s oceans were home to a true giant of the sea. The Shastasaurus, the largest marine reptile ever known to have existed, roamed these waters with a presence that was truly awe-inspiring. Unlike any other ichthyosaur, its appearance was distinct and remarkable.

Known for their streamlined bodies and long snouts that enabled them to catch fish and other prey with ease, the Shastasaurus possessed an unusually short, toothless snout that suggested a unique feeding strategy that remains unknown to this day. And this behemoth was truly a titan among its peers, with a staggering estimated length of 21 meters, and a weight of a whopping 81.5 metric tons.

To fathom the size of the Shastasaurus, imagine a creature as long as a tennis court (24 m) and as heavy as 12 fully grown African elephants. It was truly a sight to behold and a testament to the wonders of the natural world.   

So while dinosaurs may be the most well-known giants of the reptile world, there were many other species that also reached impressive sizes. These creatures are often overlooked or forgotten in popular culture and media. Learning about them can provide us with a greater appreciation for the diversity of life that has existed on our planet throughout its history.  

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