Buzz
After the great response to the previous list of prehistoric monsters, I felt compelled to present a follow-up list featuring the creatures that almost made it onto the original list. I appreciate all your feedback on the first list. I hope you enjoy this new one, and have a wonderful Easter!
10. Basilosaur
Basilosaurs were early whales that resembled sea serpents, with small, reptile-like heads and long, slender bodies. They lived during the Eocene epoch, a time when oceans were warm, so they didn’t need to store large amounts of fat to regulate their body temperature in colder waters like modern whales do. These creatures were the dominant predators of their time, preying on anything they could capture, including sharks and smaller whales. The largest Basilosaurs reached lengths of 20 to 30 meters. Interestingly, when the first Basilosaur fossils were discovered, they were initially believed to belong to a giant sea lizard or snake, which is why they were given the name that sounds like a dinosaur!
9. Argentavis
Argentavis was the largest flying bird ever known, with an impressive wingspan of 8.5 meters! This is even larger than most pterodactyls. Argentavis lived in South America and resembled a massive vulture. It was part of a group called teratorns, which were similar to today’s condors but had better adaptations for a predatory lifestyle, rather than just scavenging from the kills of others. Some experts believe that the smaller relatives of Argentavis might have inspired the Thunderbird myths in Native American culture. However, Argentavis itself never encountered humans, as it went extinct around 6 million years ago.
8. Dunkleosteus
A massive, armored fish that dominated the oceans during the Devonian period, long before sharks became the apex predators. This creature could grow up to 10 meters in length and had jaws shaped like double-edged blades. It possessed one of the most powerful bites in history, with some scientists suggesting it could even bite through metal if it were alive today! Dunkleosteus was also shielded by thick, plated armor, making it slower than modern sharks. However, since its prey wasn't particularly fast either, this wasn't much of a disadvantage. There was only one thing Dunkleosteus feared: larger members of its own species. Evidence suggests that these fish sometimes turned on each other as prey.
7. Chalicothere
The Chalicothere was an ancient relative of horses, but instead of hooves, it had sharp claws that served as effective weapons against predators. To prevent its claws from wearing down, the Chalicothere walked on its knuckles, much like an ape. This odd creature likely appeared as a strange mix between a horse, a gorilla, and perhaps even a giant sloth. It lived across Africa, Eurasia, and North America from the Eocene to Pliocene periods. Despite its intimidating appearance, the Chalicothere was entirely herbivorous.
6. Sea scorpion
Though closely related to scorpions, these creatures actually belonged to a different group called eurypterids, which dominated the oceans during the Ordovician period and survived for millions of years before becoming extinct at the end of the Permian period. These giant marine arthropods resembled a strange mix of scorpions and lobsters, with a tapering tail that could either feature a venomous, harpoon-like spine or a flat swimming fin, depending on the species. While they were capable of surviving on land, they spent the majority of their time in the water, preying on any smaller creature they could catch. The largest sea scorpions could grow to over three meters in length!
5. Mosasaur
Mosasaurs are often mistaken for marine dinosaurs, but they were actually more closely related to modern lizards and snakes. These fearsome reptiles ruled the oceans during the late Cretaceous period and were incredibly hungry predators. The stomach contents of some mosasaurs included sharks, giant squid, and smaller marine reptiles, even other mosasaurs. Equipped with numerous sharp, serrated teeth (including in the roof of their mouth!), they could grow up to 20 meters long! That’s larger than the biggest carnivorous dinosaurs, making mosasaurs the largest known predators of the Late Cretaceous (sorry, T-Rex…).
4. Doedicurus
Doedicurus was a distant relative of today's armadillos, but it could reach the size of a Volkswagen Beetle, growing up to 4 meters long and weighing as much as 2 tons. Its tail ended in a spiky, deadly club, resembling those used by knights in Medieval battles. Fortunately, this creature was a herbivore; its fearsome tail was only a defense mechanism, which proved useful against the many predators it lived alongside, such as saber-toothed cats and massive jaguars. Doedicurus inhabited South America during the Pleistocene and went extinct around 11,000 years ago.
3. Pliosaur
It’s a bit surprising that pliosaurs didn’t gain widespread fame until the 1999 airing of the popular TV show *Walking with Dinosaurs*. Although they were first recognized in 1841, these gigantic reptiles were the undisputed rulers of the Jurassic and early Cretaceous seas. In fact, they include the largest known predatory animals in history. Some, like Liopleurodon and Kronosaurus, reached lengths of 10, 15, or even 18 meters. Fossil fragments and bite marks found on other marine reptiles suggest that the largest of them could grow to 20-25 meters! Pliosaurs were actually my top pick for the number one spot in the previous list, but as an avid dinosaur enthusiast, I just couldn’t resist putting Spinosaurus in its place. Oh well...
2. Megalania
Formally known as *Varanus priscus*, Megalania was a massive lizard closely related to today's Komodo dragons. However, it was far larger, growing up to 7 meters long or possibly more. Its teeth were razor-sharp and serrated, much like those of carnivorous dinosaurs. Like its modern relatives, Megalania was likely venomous (recent studies have shown that monitor lizards produce venom, and combined with the harmful bacteria in their saliva, it explains the Australian Aboriginal saying, ‘a goanna’s bite never heals’). Its venomous bite and lethal teeth allowed it to hunt and kill massive prey, including rhinoceros-sized marsupials that roamed Australia during the Pleistocene. What makes Megalania truly terrifying is that it coexisted with humans and likely preyed on them from time to time before going extinct around 40,000 years ago.
1. Elasmotherium
Elasmotherium was an enormous rhinoceros that roamed the steppes of Asia during the Pliocene and Pleistocene periods. Weighing in at 7 tons, it was as hefty as a Tyrannosaurus rex! This mighty creature had a single, two-meter-long horn protruding from its forehead, and some researchers suggest it might have inspired the earliest unicorn legends within its native range. (Personally, I think that’s a great idea, far cooler than a tiny pony, but that’s just me…) Elasmotherium was also remarkable for its long legs, which were longer than those of most other rhinos, allowing it to gallop at surprisingly high speeds despite its massive size. It’s possible that once fully grown, this colossal beast had no natural enemies at all.
+ Pelorovis
Pelorovis was an ancient relative of today’s grumpy Cape Buffalo, but much larger, standing up to 2.10 meters tall at the shoulder and sporting extraordinarily long horns. Fossilized Pelorovis horns measure about one meter, but when the animal was alive, they were covered in a keratinous sheath, stretching their length to more than two meters! If Pelorovis shared its living relative’s temperament, it was likely one of the most dangerous animals of its time. It went extinct relatively recently, around 4000 years ago, meaning it was still roaming the African plains when the Great Pyramid of Egypt was being constructed!
