25 Strangest Prehistoric Creatures To Rule The Earth

Posted by , Updated on January 26, 2024

What are the strangest prehistoric creatures you can recall? Is the Helicoprion one of them? How about the Glyptodon. It’s difficult to image, but there was once a time where our planet was host to a wilder, more dangerous, and by far scarier place. Modern day’s toughest predators such as the great white shark, tiger, bear, and lion look feeble in comparison to some of the hulking beasts which terrorized the planet back then. From a bird with a wingspan over 40 feet to an ocean predator with teeth so plentiful they hung out of its mouth like massive scissors, prehistoric animals were simultaneously strange looking and terrifying. Today, we will show you some of the strangest, scariest, and most bizarre creatures, even by the standard of their own times. These are 25 strangest prehistoric creatures to rule the Earth.



RodhocetusSource: Cetacea (Mammalia): Evolutionary Pattern and Developmental Correlations" (2002), Image: Wikimedia

Rodhocetus gives us a clear example of a species’ evolutionary transition from land-dweller to sea-farer. One of the best-known animals in the Cetacea infraorder (which includes whales, dolphins, and porpoises), Rodhocetus had short limbs ending in webbed hands and feet. Its characteristics closely resemble those of land mammals, thus leading scientists to conclude it was part-way along the evolutionary transition from land to sea.



Pelagornithidae-skeletonSource: Journal of Vertebrate Paleontology, Image: Wikimedia

If every letter in Pelagornithidae’s name was equal to a foot, it still wouldn’t equal the size of this massive prehistoric creature. Boasting a wingspan between 15-20 feet (5-6 m), Pelagornithidae were the dominant seabirds of most oceans and even brushed up with our earliest ancestors.



TitanoboaSource: Science Daily, Image: Wikipedia

Made popular by the Smithsonian Channel TV Show, Titanoboa is simultaneously the largest, heaviest, and longest snake known to man. Appearing during the Paleocene age just after the extinction of dinosaurs, Titanoboa was so muscular it crushed its gigantic prey to death with massive force. Its discovery was especially important as it showed Earth’s tropical areas were likely warmer than we expected.



PlatybelodonSource: Paleobiology, Image: Wikipedia

Nicknamed the “shovel tusker”, the Platybelodon looks like a modern day elephant with one major difference: its trunk. This strange prehistoric creature did not have a typical fleshy trunk but rather a flat protrusion comparable to an elongated duck’s bill. Scientists believe it used the shovel tusks to grasp tree branches and rip off bark.



eurypteridSource: Quarterly Journal of the Geological Society of London, Image: Wikipedia

A combination of two of humans’ biggest fears – alligators and scorpions – Eurypterid was like a scorpion which, from one found fossil, could reach the size of an alligator. Primarily an ocean-dweller, this creature was not a true scorpion. Found all over the world, Eurypterid finally went extinct during the Permian-Triassic extinction event 252.17 million years ago. Most only grew up to 8 inches (20 cm) long, but the infamous subspecies Jaekelopterus was bigger, making it the largest arthropod yet discovered.



PterodaustroSource: The Illustrated Encyclopedia of Pterosaurs, Image: Wikipedia

Pterodaustro is one of the best known pterosaurs (flying reptiles) in the world. Found in South America, the Pterodaustro notably used a thousand bristle-like teeth protruding from its lower jaw to filter plankton and small crustaceans as it waded through shallow pools. The bill with teeth accounted for up to 85% of its head.



OpabiniaSource: Philosophical Transactions of the Royal Society, Image: Wikipedia

Only a few inches long with five eyes to navigate its seafloor home, Opabinia looks like it could have been a mad scientist’s invention. Though not a fierce predator, Opabinia was an odd-looking prehistoric creature sporting a unique, vacuum hose-like attachment at its mouth which it used to bring food back to its mouth (much like an elephant’s trunk). Beyond its five eyes, it also had 30 flippers.



meganeuraSource: Grzimek's Animal Life Encyclopedia. 2nd Edition., Image: Wikimedia

If you get scared by a wasp or a bee, you wouldn’t have fared too well in prehistoric times. Meganeura (the name sounds big enough) was prehistoric time’s massive dragonfly. With a tip-to-tip wingspan up to 2.5 feet (75 cm), Meganeura was large enough to devour frogs and small amphibians and is the largest known flying insect species.



hallucigeniaSource: Nature, Image: Natural Math via Flickr

By far one of the strangest prehistoric creatures on this list is Hallucigenia. At max 1.38 inches (3.5 cm) long, this creature was originally constructed upside down and with its back and front reversed when scientists first created models. An ancestor to either arthropods or worms, Hallucigenia had 7 or 8 pairs of legs with rigid spines correspondingly coming out the top of its body.



GlyptodonSource: The Field Guide to Prehistoric Life, Image: Wikipedia

About the size of a VW Bug, the Glyptodon was an armadillo-like creature which actually would be more related to modern-day turtles. Sporting over 1 inch-thick (2.5 cm) scales, the Glyptodon was a herbivore and, unlike turtles, could not retract its head; instead, it had a bone-like cap on its head.



EstemmenosuchusSource: Prehistoric Wildlife, Image: Wikipedia

Translated from Greek to mean “crowned crocodile”, Estemmenosuchus is quite a strange looking prehistoric creature. Though it looked like a hippo-rhino mix, this creature had distinctive knob-like horns on the sides of its head (and, in some species, on the top and on the jawbone). Thankfully, it was primarily a herbivore.



ArctocyonSource: Classification of Mammals Above the Species Level, Image: Wikipedia

Capybaras aren’t feared animals today, but this prehistoric animal was far from cute and cuddly. Nicknamed the “bear dog”, Arctocyon could walk around on its hind legs and tear apart whatever it sunk into with its razor sharp teeth.



DunkleosteusSource: Science News, Image: Wikimedia

Though it looked like a squished (though terrifying) sardine, Dunkleosteus holds the record for the strongest bite of any animal, living or extinct. Able to fit a human in its mouth with one chomp, this bizarre prehistoric creature ruled the seas for 20 million years, leaving destruction in its wake. A pure carnivore, Dunkleosteus could weigh as much as an elephant and reach up to 33 feet (10 m) in length.



terror birdSource: Journal of Vertebrate Paleontology, Image: Wikipedia

Flightless birds with similar characteristics to the ostrich, Phorusrhacids could reach land speeds comparable to cheetahs. Up to 1,000 pounds (454 kg) and 9 feet (3 m) tall, these creatures could easily grasp a medium-sized dog in a single bite (and their hooked bill allowed them to tear into larger animals as well.) They really deserve their nickname, the “terror bird”.



The_Snake-necked_ElasmosaurusSource: Sachs, S. "Redescription of Elasmosaurus platyurus" (2005), Image: Wikimedia

If you’ve ever experienced whiplash, you can imagine how tough a life this plesiosaur had. With a body which was mostly neck, Elasmosaurus was originally put together by paleontologists the wrong way: with a short neck and elongated tail. (It was also originally depicted as having a flexible, snake-like neck which has since been refuted.) Measuring about 46 feet (14 m), Elasmosaurus prowled the oceans at a length of nearly four Mini Coopers end-to-end.



HelicoprionSource: Journal of Paleontology, Image: Wikimedia

Dunkleosteus may have been big, but Helicoprion holds this list’s top spot for most bizarre, sea-dwelling prehistoric creature. Helicoprion was an ancient shark-like fish with a modified jaw: its lower palate was a circular saw of teeth which could tear flesh from bone, grinding the flesh against its top teeth.


Edestus Giganteus

EdestusSource: fmnh.helsinki.fi, Image: Wikipedia

Related to the Helicoprion, Edestus Giganteus was as terrifying as it was strange. Commonly referred to as the “scissor-tooth shark”, Edestus Giganteus had an interesting set of chompers. Rather than replace its teeth as they wore out, it would grow new teeth and gums at the back of its mouth, pushing older teeth and gums out of its mouth. The older teeth would eventually protrude and hang out of its mouth.


Diprotodon Optatum

DiprotodonSource: Science & Nature, BBC, Image: Yun Huang Yong via Flickr

Diprotodon Optatum is the largest known marsupial (mammal with a pouch) to have ever existed. About the size of a hippopotamus and comparable to a wombat with saggier skin, Diprotodon Optatum lived in Australia during the Pleistocene period and may have run across our relatively-near indigenous ancestors.



Linhenykus_monodactylusSource: Proceedings of the National Academy of Sciences, Image: Julius Csotonyi via Wikipedia

Linhenykus doesn’t look that different from our general conception of dinosaurs bar one big (well, little actually) feature: its finger. Linhenykus had only one tiny finger on each of its arms, the only non-avian dino to have but one. Scientists still aren’t sure the purpose, especially given its large feet.



LongisquamaSource: Paläontologische Zeitschrift, Image: Wikipedia

Longisquama is a lizard-like creature with what appears to be hockey sticks longer than its whole body jutting out of its back. Paleontologists know little about this reptile found in Central Asia and a long-standing debate continues on whether Longisquama was a prehistoric bird or something else entirely.



SharovipteryxSource: Paleobiology, Image: Wikipedia

With the ability to glide similar to delta-winged (triangle-shaped) aircraft, Sharovipteryx was a master of long-distance travel. Found in Kazakhstan, this one-foot-long (30 cm) prehistoric creature had membranes attached above and below its hind legs which provided for gliding (but not flight).



EpidexipteryxSource: Nature, Image: Wikimedia

In contrast to most of the massive prehistoric creatures on this list, Epidexipteryx was a tiny prehistoric creature. Presumably the first example of ornamental feathers (think of a peacock), Epidexipteryx grew up to 17.5 inches (44.5 cm) with almost half of that encompassing just the tail feathers. This feathered dinosaur lived during the Middle or Upper Jurassic age throughout Inner Mongolia.



QuetzalcoatlusSource: Journal of Vertebrate Paleontology, Image: Wikipedia

A legendary creature possibly referred to as the serpent god in Aztec mythology, Quetzalcoatlus was as tall as a giraffe while roaming on its feet. Once it took to the sky, its wingspan was from 30-40 feet (10-12 m) – that’s as long as most buildings in Paris are high. A lizard-like creature, Quetzalcoatlus may also have been what our ancestors referred to as dragons.



StethacanthusSource: Elasmo Research, Image: Wikimedia

Sporting an upper dorsal fin which looked like the top part of the Starship Enterprise, an adult male Stethacanthus lived about 320 million years ago. A pretty typical shark otherwise, Stethacanthus likely used its unique dorsal fin in mating rituals or to scare away predators.



spinosaurusSource: Bulletin of the Natural History Museum, Image: Raphael041 via DeviantArt

The T-Rex pales in comparison to the massive but lesser-known Spinosaurus. Reaching up to 59 feet (18 m) long, this prehistoric beast could weigh more than a semi-truck and the webbed spines on its back could have easily reached the height of a basketball player. Spinosaurus’s alligator-like mouth likely means it was a major fish eater and spent much time in the water. Makes us wonder whether those back spines could have been used for swimming.