Top 10 Scariest Extinct Animals That Ever Lived

Extinction is a very serious issue facing our world. But when it comes to these extinct animals, we have to admit: We’re kinda glad we don’t have to face off against them, which could crush today’s titans with ease.
The ancient Earth was full of monstrous beasts that grew to a scale unlike anything alive now, and a lot of it has been freaking terrifying. Many modern species, the big and the small alike are dwarfed in comparison to their prehistoric relatives.

Take a look at these 10 ancient creatures and be glad they’ve gone extinct. We’ll all be having bad dreams tonight.

Saber-toothed Tiger

What would you say is the most famous Ice Age predator? Many folks probably first thought of the saber-toothed tiger. But did you know that these fearsome beasts weren’t actually tigers or even all that closely related to them? Kind of like that other famous Pleistocene predator the dire wolf, which in turn wasn’t really a wolf.

The saber-toothed tiger roamed freely in the Americas from around 2.5 million years ago until the species went extinct around 11,700 years ago. It was an apex predator and killed large animals by hunting in packs. Even an American Mastodon that stood over 10 feet (3 meters) tall and weighed up to 12 tons (5,455 kg.) was not safe from this predator.
Its only true enemy was human beings. Human hunters and temperature changes are thought to have driven this animal to extinction.

saber toothed tiger

Saber-Toothed Tiger of North America

Saber toothed cat 2

Life-size Saber-toothed Tiger Skeleton


Megalodon is an extinct species of giant shark that lived between 28 to 1.5 million years ago, from the Early Miocene to the Pliocene. Its name means “big tooth”, and we can imagine why.

Megalodon had a bite force of over 20 tons. In comparison, the modern-day Great white shark has a bite of 1 ton. Considering that a modern-day Great White has jaws powerful enough to bite through the bones of whales, then one can only imagine how deadly this predator’s bite would have been.

Megalodon tooth

Megalodon tooth with two great white shark teeth

Thanks to its incredible size of up to 18 meters (59 feet), it is considered one of the largest and most powerful predators that have ever existed on Earth.
It could weigh up to 65 metric tons (143,000 pounds), look like a giant, more terrifying version of the modern great white shark, and could be found worldwide.
Megalodon was the apex predator in its environment and evidence shows that it would have preyed mostly on large whales. Among ts favored prey would have included the ancestors of the modern-day Sperm Whale, a super predator itself.


Megalodon,gigantic shark


Not many animals can prey on crocodiles, but the giant snake Titanoboa cerrejonensis was one such beast. It grew to colossal proportions, often reaching 13m in length and weighing more than 1,100kg, with a body so thick it would reach up to a man’s waist.
Like modern-day anacondas, Titanoboa used to lie in wait beneath the surface of a lake or river. Any prey that came close was swiftly seized and dragged underwater. Here the snake would entwine its struggling victim, before constricting to finish it off.



Arthropleura was a distant relative of modern millipedes and centipedes – an arthropleurid anthropod. It grew to 2.3 meters in length, as tall as a man and as long as a car.

It is the biggest land arthropod known to humans. The reason why they were able to grow so big is that the oxygen level was 50% higher than it is today. The higher oxygen content in the atmosphere could support larger species whose circulatory system was not as efficient as those of mammals and other species.

Fossil of Arthropleura, an extinct arthropod

Fossil of Arthropleura, an extinct arthropod

Arthropleura lived in the Carboniferous forests, approximately 323-299 million years ago. They became extinct shortly before the Permian when forests were decreasing and the landscape was becoming dryer.


Life Before the Dinosaurs: Arthropleura


When you think of enormous reptiles from the Cretaceous period, you’d be forgiven if your first thought was T. rex. But while dinosaurs are often the star of the show, they were far from the only ones.

Take Sarcosuchus imperator, for example. Sometimes called ‘super croc’, this predator is not the sort of beast you’d want to bump into. It’s thought that this species of crocodile, thankfully.

It is an extinct genus of crocodyliform and distant relative of living crocodilians that lived during the Early Cretaceous, from the late Hauterivian to the early Albian, 133 to 95 million years ago of what is now Africa and South America. It was one of the largest crocodile-line reptiles, reaching an average estimate of 9 m (30 ft) and 3.5 metric tons (3.9 short tons), but estimated to grow up to 9.5 m (31 ft) in body length and weigh up to 4.3 metric tons (4.7 short tons).


Sarcosuchus: The ‘super croc’ that could have hunted dinosaurs

Sarcosuchus fossil

Sarcosuchus in the National Museum of Natural History, Paris


Early humans had to compete with many fierce predators, and Arctodus Simus was among the greatest. Bigger than any bear alive today, it stood 4m tall, weighed up to a tonne, and could bring down bison.
Arctodus, or the North American short-faced bear, is an extinct bear genus that inhabited North America from the latest Pliocene to the Holocene epoch, from ~2.5 Mya until 10,000 years ago. Today considered to be an enormous omnivore, Arctodus was the most common short-faced bear in North America. There are two recognized species: the lesser short-faced bear (Arctodus pristinus) and the giant short-faced bear (Arctodus simus), with the latter considered to be one of the largest known terrestrial mammalian carnivorans that have ever existed.


Arctodus, short faced bear size reference chart,alongside a human for comparison

Prehistoric Animal Skeleton Arctodus Replica

Short faced Bear Skeleton
Real Size Artificial Arctodus Skeleton for Museum


If every myth is rooted somewhere, in reality, tales of fire-breathing dragons almost certainly came from the Megalania (or Varanus priscus). These distant relatives of the Komodo dragon would have weighed more than 1,300 pounds and grown to be 18 feet long.
They vanished from Australia about 50,000 years ago, which means the earliest Aboriginal people may have made contact with them. Certainly sounds like the stuff of legend to us.

Megalania fossil

Varanus priscus skeleton, Melbourne Museum


Realistic Megalania Replica for Sale>>


Scientists call the Phorusrhacidae “terror birds,” which should tell you all you need to know about these things.
No? OK: They lived in North and South America until about 2 million years ago; they could grow to be 10 feet tall, and their beaks were so strong and sharp that they could kill other animals by striking their heads downward and fatally cracking their skulls.



Dunkleosteus was a large carnivorous fish, which lived about 380 to 360 million years ago, during the Late Devonian period. It was an efficient and voracious predator thanks to its size that reached up to 10 meters (37 feet) and a weight of almost 4 metric tons (8,818 pounds). Its head and chest were covered with articulated armored plates, which made it a slow but very powerful swimmer.


Dunkleosteus Skull

animatronic Dunkleosteus 1

Realistic Life-size Dunkleosteus Model>>


Deinosuchus is an extinct genus of alligatoroid crocodilian, related to modern alligators and caimans, that lived 82 to 73 million years ago, during the late Cretaceous period. The name translates as “terrible crocodile” and is derived from the Greek deinos,

The large size of Deinosuchus has generally been recognized despite the fragmentary nature of the fossils assigned to it. However, estimates of how large it really was have varied considerably over the years. The original estimate from 1954 for the type specimen of the then-named “Phobosuchus riograndensis” was based on a skull of 1.5 meters (4.9 ft) and a lower jaw of 1.8 meters (5.9 ft) long, reconstructed with similar proportions to the Cuban crocodile giving a total estimated length of 15 meters (49 ft).

Deinosuchus live

animatronic Deinosuchus 2
Aanimatronic Deinosuchus for Sale

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