Monster Crocodiles, Part 2: Primeval

by guest writer and artist Hodari Nundu

Crocodylus thorbjarnarsoni seizes its prey

Go to the beginning of this series

The reason why crocodiles are more dangerous than sharks is that we are much more likely to meet them, and when we do, the crocodile is more likely to see us as prey than the shark.

According to many shark experts, these fish bite people for a variety of reasons but many attacks seem triggered by curiosity rather than actual predatory urges. Sharks lack hands and fingers to examine new, unknown objects. They often explore things by biting them. This is why, even if a great white shark does not necessarily want to kill a human being, an innocent exploratory bite can spell doom for its victim.

Crocodiles, on the other hand, have always seen us as prey. Unlike sharks, they coexisted with us from the very beginning. When our primate ancestors abandoned the jungle and became savannah-dwellers, crocodiles of immense size populated rivers. The fossilized remains of one of these crocodiles were found recently in Tanzania.

They came from a monster up to 7.5 meters long- larger than the largest Nile or Saltwater crocodiles recorded for our times. The beast had a huge, heavy skull adorned with a pair of crests or "horns" which revealed it to be a different species from today's Nile crocodile. Scientists named it Crocodylus anthropophagus, the "man-eating crocodile", as bite marks that matched its teeth perfectly had been found in the bones of our hominin ancestors. An even larger species, Crocodylus thorbjarnarsoni, lived at about the same time in Kenya. This one was 8.2 meters long, or as the press put it, “big enough to star in Lake Placid”. 

Because crocodiles lived in rivers, which were vital to the survival of humans, there was simply no way of escaping them. Other predators, like big cats, wolves and hyenas, could be frightened with fire and other weapons. Crocodiles were different. Like sharks in horror movies, they waited under the surface, invisible, and attacked by surprise; and once they had you in their clutches, they were simply too powerful to be fought.

Even the arrival of civilization couldn´t stop crocodile attacks. In Ancient Egypt, land predators such as lions and leopards were slowly exterminated, and attacks became a rarity. Crocodiles, on the other hand, were an ever present threat along the edges of the Nile. The Egyptians even had a special god, the crocodile-headed Sobek, to protect them from the voracious reptiles. There's even a legend from more recent times about an archaeologist in Egypt who found a statue of Sobek by the river; removing it, however, was a mistake, as crocodile attacks became incredibly frequent, and eventually, he was forced to put Sobek back in his place; only then did the attacks stop.

To the Greeks and other Europeans, the crocodile was a most fascinating beast. Absent in Europe, it was therefore little understood, and in Medieval bestiaries, it is often shown with a wolf or lion-like appearance, sometimes with spikes on its back, and more often than not, weeping over the body of a human victim. For according to many authors of the time, "if the crocodile findeth a man by the brim of the water or by the cliff, he slayeth him if he may, and then he weepeth upon him, and swalloweth him at the last".

This tendency to shed tears during a meal eventually would make the crocodile a symbol of hypocrisy, of false remorse. The expression "crocodile tears" is a legacy of this legend, which has indeed a real life basis. Crocodiles do shed tears while feeding. But these are not tears of remorse, false or otherwise. It is simply the crocodile's way of keeping its eyes moist while out of the water, for it cannot swallow under the surface, and its eyes easily dry out in the air.

In Roman times, crocodiles were sometimes seen at the Coliseum. The amphitheater was flooded and epic naval battles were recreated. Crocodiles were released into the water to devour any hapless gladiator or slave that fell from the ships.

Other than this, however, the crocodile remained more or less a fantastic animal in Europe for a long time. Unable to survive for long in cold climate, the crocodile was restricted to tropical regions. But wherever it was found, it was a constant danger along waterways, a dreaded and often revered force of nature.

To the Aztec and many other Mesoamerican cultures, the Universe itself rested on the back of a gigantic crocodile-like beast. The souls of the departed had to face a terrible crocodile god during their journey towards Paradise.

But although modern day crocodiles are big, scary and deadly enough to inspire legends, nightmares and B movies, the truth is we only have to deal with a shadow of what was once a frightening menagerie of monster crocodilians.

We often think of crocodiles as "living fossils"; many people, including crocodile experts, will tell you that they haven´t changed much in millions of years.

This is only half true. The basic design of all modern crocodiles- the low body, short legs, long flattened tail and deadly jaws that make them such perfect ambush predators- has indeed existed for millions of years. It has even been "used" by non-crocodilian predators, including early whales and gigantic amphibians from pre-dinosaur times.

But crocodiles themselves are of rather recent origins, and they are only one of many branches of crocodylomorphs, as scientists call them. Some of these branches were truly the stuff of nightmares.


Like their cousins the dinosaurs, crocodylomorphs started out small. The first ones appeared in the Late Triassic, over 200 million years ago, and they coexisted with the very first dinosaurs.

They were small, agile and completely land-based. Rivers were already occupied by other sorts of predators—giant amphibians resembling large-headed salamanders, and the fearsome phytosaurs, which looked quite a lot like crocodiles themselves. Crocodylomorphs would have to wait until these rivals disappeared to fill the niche of the freshwater predator themselves. Meanwhile, they diversified into plenty of different and often bizarre breeds.

This diversification became most extreme during the Jurassic period. To avoid competition with dinosaurs, many became aquatic. The most extraordinary ones were the sea crocodiles.

Today, the saltwater crocodile often lives in coastal waters and may even swim long distances from island to island. They have been seen fighting- and devouring- sharks in the sea. But they are still amphibious animals, and must return to land to rest and to lay their eggs.

The sea crocodiles of the Jurassic were different. They became so well adapted to the ocean that if one of them appeared today, we would probably mistake it for some sort of bizarre mutation- a cross between a crocodile and a fish. Many of them lost their body armor; their webbed feet turned into actual flippers, and their tails turned into caudal fins, very reminiscent of a shark's.

They probably gave birth to live young, like many other sea reptiles of the time. Free from the need of returning to land, they spent their lives in open waters. Many, like Metriorhynchus, had long, slender snouts that would resemble some living crocodilians, like the gharial; they were superbly adapted to capture fish. Usually, they measured about three meters long-- smallish compared to our largest crocodiles-- but they were far better swimmers.

Dakosaurus vs. the predatory marine reptiles known as Eurhinosaurs

Not all of them were fish eaters, however. In 1987, the remains of an unusual (well, especially unusual) four or five meter long sea crocodile were found in Argentina. Instead of a long gharial-like snout, it had a short and deep skull, very reminiscent of a carnivorous dinosaur's. The scientists nicknamed it Godzilla for this reason.

A later study found that this sea crocodile, formally known as Dakosaurus, could slice its prey into smaller chunks with its large, blade-like serrated teeth. This is completely different to the teeth of modern crocodiles which are conical and blunt, meant to pierce and hold but completely unable to slice.

Indeed, Dakosaurus was a crocodile turned by evolution into the Jurassic equivalent of a great white shark. It didn´t chase after small fish like its cousins; it went for the giant ichthyosaurs and plesiosaurs of the time, even those larger than itself, and bit off huge chunks of their flesh, killing them via blood loss. With monsters like Dakosaurus roaming the seas, it is little wonder that, to our knowledge, no dinosaurs ever managed to conquer the Jurassic oceans.

Machimosaurus attacks Dakosaurus, to the alarm of a dinosaur called Eustreptospondylus

As if Dakosaurus wasn´t scary enough, the Jurassic sea would give rise to even larger crocodylomorphs. The largest we know of was Machimosaurus, found in Europe in 1837. Unlike Dakosaurus, it had a crocodile-like body and blunt, conical crocodile teeth. However, it was big enough to make a meal out of Dakosaurus- at least 9 meters long, making it not only the largest of its kind, but also one of the top predators of its days.

Although its snout was long and slender, there's good evidence that Machimosaurus, being so large, could feed on anything it wanted and not just fish. Its bite marks have been found in the fossilized shells of sea turtles and even in the bones of a giant long-necked dinosaur.

Scientists believe Machimosaurus swam long distances in the open sea, but probably hunted near coasts, snatching any unfortunate animal that got too close.

Machimosaurus was only the first in a long line of crocodylomorphs (from different families) that achieved monstrous sizes.

During the Cretaceous, both dinosaurs and crocs would reach their greatest diversity. The largest carnivorous dinosaurs, such as Spinosaurus, Carcharodontosaurus, Giganotosaurus and of course, the iconic Tyrannosaurus rex were all from the Cretaceous. The biggest of them all, Spinosaurus, could weigh up to 9 tons. But the largest Cretaceous crocodiles dwarfed even this monster.

Sarcosuchus puts a dinosaur to flight

In 1966, two paleontologists named a new species of Cretaceous crocodile as Sarcosuchus imperator, the flesh-eating emperor croc. Despite its awesome name, this beast remained obscure until 1997, when American paleontologist Paul Sereno found additional remains in Niger.

These new finds were widely publicized and Sarcosuchus finally became famous under the nickname of Super Croc. It was its monstrous size that captured the public's imagination; at 12 meters long, with an almost 2 meter skull and probably up to 10 tons, it was claimed to be the largest crocodile of all times.

Sarcosuchus coexisted with large carnivorous dinosaurs such as Suchomimus, but the general consensus is that it was the dinosaurs, rather than the crocodile, who were in constant danger of being eaten. After all, dinosaurs had to drink, and an adult Sarcosuchus was too big to survive solely on fish.

As if this wasn´t bad enough for the hapless dinosaurs, they had another crocodilian enemy on land.

The remains of this creature were also found by Paul Sereno, and described in 2009. It was obviously a crocodile, but unlike any other crocodile ever found. It had a pair of horn-like crests on its head, and some of its teeth jutted out of the mouth like enormous tusks. The creature received the nickname of Boar Croc, and was described as "a sabertooth tiger clad on armor". It was not a water-based ambush hunter. It was a land-dwelling predator able to walk and run at high speed, and its enormous teeth were probably an adaptation to deal with large, thick skinned prey; a six meter long dinosaur hunter.


  1. Should have mentioned that when the teeth of sebecids were first found in South America, paleontologists thought they were evidence of late survival of giant carnivorous dinosaurs into after the Cretaceous.

  2. That's interesting. I seem to remember hearing quite a few stories of fossils misinterpreted on first look.

    1. I am guilty of it myself- I went out fossil hunting one day and found many small pieces of what I took to be turtle shells. Imagine my surprise when I did some research and found that they were actually bits of a glyptodont's shell- basically an armadillo the size of a Volkswagen beetle.

  3. Wow. That sounds like an amazingly cool find!

  4. I was to think that a beast that big is the apatite must be on going.
    animal Wayne 2000 some on pounds with the wind vicious bite make you think that they kill just to be killin.


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