The animal kingdom is a truly wonderful thing. It contains all types of living creatures that live in a huge range of different habitats and environments, making them all vastly different from one another. For the most part, humans get along relatively peacefully with the other organisms that surround us in our everyday lives. This is simply because there are few animals that are a danger to us and those that are potentially threatening are usually located well away from any human population.
That isn’t to say that there aren’t creatures that are frightening. People are scared of all types of things, ranging from phobias of insects and spiders, to being alarmed by huge carnivores such as crocodiles, sharks and bears. However, even these monstrous beasts are nothing compared to the prehistoric monsters that once lived. Fortunately, most of the truly terrifying creatures that once roamed the world are now extinct, because they are truly exceptional in their ability to cause nightmares.
Some of the examples in this article are horrific simply because of their size, while others have gruesome appearances or barbaric hunting methods that make them something that no one would ever want to encounter. Whatever the case, it is painfully obvious that we wouldn’t have been able to survive around such creatures (but they would make excellent material for horror movies).
Azhdarchid was a species of Pterosaur, a flying reptile that many people consider to be winged dinosaurs. This is inaccurate however, with the extinct creatures actually belonging to a different family of organisms much like the gigantic marine reptiles that were around at the same time.
Their name comes from the Persian word for dragon, and it is little wonder why when you consider that these monstrous creatures stood at around the same height as a giraffe with a wingspan of more than 50 feet. They also feature a very large head and toothless beak that is almost the same size as its torso, allowing it to eat fairly large animals compared to other similar species. Due to its large size, there has been some debate over whether Azhdarchid would be able to fly and consequently, how they would feed. Most researchers now conclude that it would be able to soar over long distances and would hunt small animals on the ground.
Often known as the killer pig, the entelodon is an extinct form of pig-like omnivore that lived around 37 million years ago. These huge creatures could be found across North America, parts of Europe and even Asia. Like their modern-day relatives, entelodons had a diet that consisted of both meat and vegetation, meaning that they had incredibly sharp teeth. However, they also differed significantly thanks to the large size of their cloven hooves.
Perhaps the most significant feature of these terminator pigs was the huge horn-like structures on their heads, much like a warthog. Fossil evidence points to the fact that the animals would often fight each other, leaving staggering wounds that could be up to an inch deep in skulls. This immense power shouldn’t be too surprising considering they stood at around 4 feet tall and 10 feet long, weighing in at 1,000 pounds.
Unlike the vast majority of marine reptiles that are alive today, that range from turtles to alligators, liopleurodon was a truly massive creature. It lived in the oceans for around 5 million years before dying out some 155 million years ago. While accurate estimates of its size are difficult to calculate due to the small amount of fossil evidence available, most experts believe they were likely to be around 30 feet long. This would mean that they would weigh an astounding 3,500 pounds and would be able to hunt almost any other creature living in the waters in which it roamed.
As an apex predator, the liopleurodon would track prey using its strong sense of smell and then attack them with a strong jaw filled with hundreds of razor sharp teeth. Unlike crocodiles or alligators, it was unable to leave the water thanks to its flippers, which it could use only to swim.
The gigantopithecus has jumped into the public consciousness in recent times, despite being relatively unknown for hundreds of years, thanks to the fact that it appeared in Disney’s live-action version of The Jungle Book. They were essentially giant orangutans that lived around 100,000 years ago in the forests of India and China. In fact, their size was so immense, with fossils indicating that they could have been as tall as 10 feet and weighed upwards of 1,100 pounds, that they are the biggest ape to have ever existed.
While their enormous figure obviously provided many advantages and made them almost immune to predators, it also led directly to their downfall. Experts believe that the large size of the gigantopithecus meant that it was particularly susceptible to environmental pressures that it encountered when the climate changed significantly.
Although many people have ideas about sabretooth tigers simply being very large cats, the xenosmilus was different in that it wasn’t just large but built heavily with very large muscles. This gave it an appearance of a cross between a leopard and a bear. This unique look and build meant that it hunted in a different way to the vast majority of saber-toothed cats. Using its distinctive cookie-cutter jaw, it would simply use its strength to tear huge chunks of muscle and flesh from its prey so that it would slowly die from blood loss as it tried to escape.
Estimates from fossils that have been found in Florida suggest that this cat could have been as large as 6 feet long and had a total weight of 900 pounds. This would make it one of the largest big cats to have ever lived and a truly terrifying predator.
Only found when remains were uncovered in Morocco in 2014, the Aegirocassis is a type of sea creature that is closely related to modern day lobsters. It was capable of growing in excess of 6 feet long, making it around the same size as a fully grown adult human. Dr Allison Daley, of Oxford University, said: “This would have been one of the largest animals alive at the time.”
Aegirocassis wasn’t a vicious predator, however. Instead of hunting prey with long sharp teeth or giant claws, it fed much like whales do today. It sucked large amounts of water into its mouth and then used its specialized teeth to filter out food that it could then digest. The lobster-like creature is considered to be the oldest example of a giant filter-feeding organism.
9. Argentavis Magnificens
Fossil records demonstrate that argentavis magnificens was likely to be the largest bird that has ever taken to the skies. Standing as tall as an adult human and weighing as much as 180 pounds, it was unlike any bird that is alive today. Unlike other large avian species though, it was unlikely to act as a predator, as it wasn’t built to specialize in hunting prey. Experts believe it is more likely that the huge creature would scavenge its food.
This immense size meant that it was unlikely that argentavis magnificens was able to fly like its modern relatives. Instead, it would soar through the air, flapping its wings only very occasionally to gain extra lift. Despite this, it was still able to travel at a speed of around 25 miles per hour, allowing it to quickly traverse its huge territory of 190 square miles.
There are few living creatures that scare people more than bugs and insects. They are such terrifying things that many horror movies prey on this fear by creating huge monsters that are simply giant versions of common creepy crawlies. The arthropleura could then be described as a horror movie made real, as it was a huge millipede that could grow to a size of up to 8 feet long. Living some 299 million years ago, they were so big that they would have had no natural predators and are considered the largest known land invertebrates that the planet has seen.
These huge millipedes would have lived in North America and Europe, near warm swamps that allowed it to grow to such a large size, which many researchers believe is the limit to how big such invertebrates could grow to on the surface.
The largest snakes alive today are capable of growing to around 25 feet in length in certain circumstances, but the Titanoboa would put them all to shame. This is because it weighed more than a ton and measured an incredible 50 feet in length. “Never in your wildest dreams do you expect to find a 14m boa constrictor. The biggest snake today is half that size,” said Dr Carlos Jaramillo, a scientist at the Smithsonian Tropical Research Institute.
Alive just after the dinosaurs died out, the snake lived mainly in the swampy jungles of South America. Like modern day boa constrictors, it was not a venomous snake and would instead crush prey to death with a force of 400 pounds per square inch. Following the death of the dinosaurs, experts believe that the Titanoboa was the largest predator on the planet for around 10 million years.
Dragonflies are not particularly frightening creatures, though some do have a phobia of them. Yet few would probably fail to be terrified of Meganeura, a species of dragonfly that was as large as a child. Having lived around 300 million years ago, the flying insect had a wingspan of 26 inches and a body length of around 1 foot. Like its modern day relatives, it was a carnivore that would most likely prey on small invertebrates and amphibians.
Meganeura was able to grow to such a large size simply because of the richer oxygen content in the air at the time. Current research suggests that insect size is largely dictated by the amount of oxygen available in the air and environment that this flying insect lived in had almost double the amount of oxygen that you would find today.
While there are certainly some very ugly and scary fish alive today, such as piranhas, they pale in comparison to the Dunkleosteus. This giant fish lived about 360 million years ago and is one of the largest fish to ever live, capable of growing up to 20 feet long and 1 ton in weight. Its great size meant that it was an apex predator that was protected from danger thanks to armor plating around its head.
A pair of large teeth and an immensely strong jaw meant that the Dunkleosteus was able to eat almost anything it came across in the water, including sharks, armored fish and even its own species. Using its incredible bite strength, it could easily tear through the flesh of any other creature alive at the time.
Discovered in 2005 by a team of researchers in a Colombian coal mine, the Carbonemys is an extinct genus of giant turtle that lived 60 million years ago. With a shell that was almost 6 feet long, its entire body was around 10 feet in length. The huge creature would have weighed 1 ton, making it a similar size to a small car.
While Carbonemys isn’t the largest giant turtle to have ever been discovered, it is probably the most gruesome. It had a unique jaw that was incredibly powerful, allowing it to hunt animals far bigger than any of its relatives. In fact, the jaws were so strong, researchers believe it would have been capable of fighting and killing similarly sized mammals or even crocodiles.
Gorgonopsia is a species of therapsid that are ancestors to modern day mammals. They were essentially a cross between reptiles and mammals that roamed the earth some 250 million years ago. Unlike many other creatures at the time, Gorgonopsia had specializations that included unique tooth shape and powerful hind legs.
One of the largest predators during the period that they lived, they were comparable in size to a large bear, with a skull that was nearly 2 foot in length. They also possess teeth that were incredibly sharp and up to 5 inches long. As they stood almost as tall as a human and were incredibly muscular, they could easily tackle prey that was bigger than themselves, even creatures that were twice their size.
Although it isn’t technically a crocodile, Sarcosuchus closely resembled the modern day reptiles, with its long body and scaly appearance. Unlikely saltwater crocodiles though, this example was able to grow to about double the size. In fact, some scientists believe that it was capable of reaching even greater sizes as it would continue to grow throughout its lifespan, enabling it to surpass 40 feet in length.
This huge size meant that they would weigh around 8 tons and have thick skin that would act as armor – something that was necessary considering it lived at the same time as dinosaurs. It was capable of eating creatures of almost any size but its main diet would have been made up of fish that swam in the area that is now the Sahara desert.
Sharks are already one of the most terrifying creatures that live on the planet today. As well as a somewhat alien quality that they possess, they are also capable killers with horrific teeth that are capable of giving anyone nightmares. Megalodon though takes the idea of a shark to the next level. These huge sea creatures were alive approximately 2.5 million years ago and are now regarded as one of the biggest and most powerful killers in history.
The giant shark was able to reach a length of almost 60 feet and looked like an exaggerated version of the great white shark. Most frightening of all was the huge jaw that held teeth that were up to 6 inches long and 4 inches wide. Due to its large size, the shark was able to eat a huge variety of prey, including whales, giant sea turtles and dolphins.