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Top 7 Scariest Prehistoric Animals That Ever Existed

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For roughly four billion years, there has been some form of life on Earth, and a lot of these prehistoric animals have been absolutely terrifying. Excellent work, evolution; you’ve ensured that everyone will have nightmares tonight.

You may also want to read about the top 8 apex predators.

But what are the scariest prehistoric animals that ever existed?

7. Helicoprion

This strange fish has eluded classification for a long time, and the mystery surrounding it began with a peculiar fossil. The origins of Helicoprion have been a mystery to paleontologists and ichthyologists for over a century. Until 2013 only a fossilized whorl of teeth remained of this creature. Scientists generally agreed that the teeth belonged in the lower jaw, but this did not stop the teeth from being moved around the body and arranged in sometimes fantastical ways in various illustrations and reconstructions.

The lower jaw was eventually pieced together, and with that, the location of its buzzsaw-like teeth was established. The odd thing was that it had no upper teeth, so it could gum you and bite you at the same time, which is pretty disgusting. When the jaw is shut, the teeth rotate clockwise, like a circular saw blade. Likely, it dined on squid and other cephalopods, which have fleshy bodies that it could easily digest.

The whorl of teeth was formed as the animal aged and the teeth grew outward in a spiral pattern, with the smallest teeth at the beginning of the whorl and the largest teeth at the end. Edestus, another fish with a peculiar and terrifying appearance, has jaws that are offset like scissor blades and project forward from its face.

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The Helicoprion is a very scary species of the prehistoric animals.

6. Smilodon

In the Pleistocene epoch, the saber-toothed cat was widespread across North and South America. Its size was comparable to that of a modern lion or tiger, but it possessed incredible upper body strength, which it used to wrangle its prey to the ground. Then, it would kill its prey with a bite to the throat or a stab to the lungs from its serrated, 11-inch long fangs. Those long teeth could easily pierce your skin and sink into your flesh if it ran you down. Its bite might have been less powerful than that of today’s big cats, but the animal was still terrifying nonetheless.


5. Spinosaurus

Undoubtedly, Spinosaurus ranks among the most impressive and terrifying predators in the history of the planet. Its elongated head resembled that of a crocodile, and its pointed snout was lined with about sixty-four sharp teeth. Since it was likely semi-aquatic, there was no safe place for fish or dinosaurs to hide from this predator. Spinosaurus has the distinction of being the largest carnivorous dinosaur ever discovered, surpassing both T. rex and Giganotosaurus in size.

Recent discoveries and studies suggest Spinosaurus may have reached 41-59 feet in length and weighed more than 20 tons, though the precise dimensions are still up for debate. Its back was covered in elongated neural spines that formed a saillike structure, amplifying the creature’s size and imposing appearance.

These prehistoric animals will definetly scare you.

4. Titanoboa

If you have a fear of spiders, this is for you. The Titanoboa snake, which lived during the Paleocene epoch, was 42 feet long. Like crocodiles, it probably hunted by lying in wait at the water’s edge, partially submerged, for unsuspecting prey. It would attack its prey from below the surface, wrapping itself around it to ensure a swift and painful death. Its habitat was the South American rain forest, which was warmer than today’s tropics. Because of this, the cold-blooded reptiles were able to attain sizes unattainable by reptiles today. Even Indiana Jones would be afraid of this snake.


3. Giganotosaurus

Giganotosaurus was 43 feet long and larger than the size of Tyrannosaurus rex, but only by 3 feet. It had a 5.2 foot long skull with 64 eight inch long compressed and serrated teeth that were made for slicing through flesh, though they were not capable of crushing bone like the teeth of Tyrannosaurus. Giganotosaurus is from the Cretaceous period and lived in what is now Argentina. It was related to the nearly equally sized Carcharodontosaurus from Africa.

Evidence suggests the possibility that Giganotosaurus was a pack hunter and that they hunted large sauropods. This would make it the only theropod that actively hunted sauropods. Another interesting feature is that the lower jaw was broadened slightly, allowing it to also handle smaller prey. It’s easy to imagine Giganotosaurus chomping down on the flesh of some goofy bipedal mammals if it had ever been given the chance.

2. Megalodon

This 59-foot long shark shared its habitat and food sources with Livyatan melvillei. Its massive 7-foot-wide jaws housed 5 rows of about 276 compressed, blade-like teeth, making it well-suited for cutting and grasping prey with significant strength. Megalodon’s jaws and a few trace fossils are all paleontologists have to go on when hypothesizing about shark evolution because sharks have cartilage skeletons that are rarely preserved in the fossil record.

Megalodons probably resembled great white sharks in overall shape, but were much larger and more powerful. If the megalodon hunted in an ambush like the great white shark, it would have ambushed its prey from below, then struck with pinpoint accuracy to immobilize it with its incredibly powerful bite. Shaking their prey from side to side can also increase the bite force of a shark’s bite. Teeth impressions discovered in whale vertebrae indicate that the megalodon was a predator of large whales. Their tooth structure was designed to make it extremely unlikely that it would break when striking bone.

The Megalodon is one of the scariest of the prehistoric animals.

1. Basilosaurus

A mere 50 million years ago, whales made the transition from land to sea. They went through a period of awkward development before maturing into the whales we know and love today (and by awkward, we mean horrifying). Consider the Basilosaurus, whose three-foot-long skull is on display in our Evolving Planet exhibit.

Scientists believe this 60-foot leviathan had a bite force comparable to that of a Tyrannosaurus rex, which it used to crack open the skulls of other, smaller whales (you can see Basilosaurus tooth marks on their skulls).

The Basilosaurus is the scariest of the prehistoric animals.