Long before humans set foot on the shores, the vast oceans were home to an astonishing array of bizarre and awe-inspiring creatures that have sadly vanished from our planet.
While we may never have the chance to lay eyes on these incredible animals, their fossils and the stories they tell continue to captivate our imaginations. Here are 10 incredible extinct ocean animals.
1. The 60-Foot Super Shark
Megalodon, meaning “big tooth”, was an ancient shark that ruled the seas from 23 to 3.6 million years ago. This colossal predator reached lengths up to an astounding 60 feet – the size of a railroad car.
Megalodon’s jaws could open wide enough to swallow two adult humans side by side, with teeth as large as a human hand.
2. The Manatee-Like Sea Cow
Steller’s sea cow, discovered in 1741, was a sirenian that grew up to 30 feet long and weighed over 10 tons. Inhabiting the sub-Arctic waters of the North Pacific, this gentle giant grazed on kelp.
Sadly, within just 27 years of Europeans discovering it, the slow-moving Steller’s sea cow was hunted to extinction for its meat and hide. (ref)
3. The Permian Buzz-Saw Shark
Helicoprion, known as the “buzz-saw shark”, was a cartilaginous fish with a unique spiraled tooth whorl resembling a circular saw. Living 290 million years ago during the Permian period, Helicoprion likely fed on soft-bodied prey like squid.
Fossils of this bizarre creature primarily consist of its distinctive teeth, making a full anatomical reconstruction challenging.
4. The Bus-Sized Armored Fish
Dunkleosteus terrelli was a 20-foot-long armored fish of the Late Devonian period, 380-360 million years ago. This formidable apex predator had bony armor and unique self-sharpening jaw plates that could crush prey.
5. The Loch Ness-Like Reptiles
Plesiosaurs were marine reptiles with long necks and flippers that lived from the Triassic to the end of the Cretaceous, 220-66 million years ago. Some plesiosaurs like Plesiosaurus grew up to 15 feet long.
These “sea monsters” thrived in the Mesozoic oceans until going extinct during the same event that wiped out the dinosaurs.
6. The Whale-Sized Sea Serpent
Basilosaurus, meaning “king lizard”, was a 60-foot-long serpentine whale that lived 40-34 million years ago during the Eocene. Initially thought to be a marine reptile, Basilosaurus was one of the first ancient whales.
With a streamlined body and powerful jaws, it was the apex predator of its time, feeding on other whales, fish, and sharks.
7, The Spiny Shark-Like Fish
Fanjingshania renovata, described in 2022, was an ancient shark-like fish covered in spiny fins and bony armor. Living 443-419 million years ago in the Silurian seas of what is now China, Fanjingshania was heralded as unlike any vertebrate ever discovered.
8. The Alien-Looking Shrimp
Opabinia regalis was a bizarre animal that lived 505 million years ago during the Cambrian period. Only 2 inches long, Opabinia had five eyes on stalks (ref) and a long flexible proboscis ending in grasping claws.
Its unusual appearance even made paleontologists chuckle when it was first reconstructed.
9. The Giant Sea Scorpion
Sea scorpions, or eurypterids, were ancient arthropods resembling scorpions that inhabited the seas from 480-250 million years ago. Some of these marine monsters grew to over 8 feet long, dwarfing modern scorpions.
One fossil eurypterid found in New York came from a sea scorpion estimated to be larger than a human.
10. The Boomerang-Headed Amphibian
Diplocaulus magnicornis was a 3-foot-long amphibian with a bizarre boomerang-shaped head that lived during the Permian period, 275 million years ago. Found in what is now Texas, Diplocaulus’ unique skull shape likely played a role in how it swam, though the exact reason for the odd head is still a mystery.
11. The Armored Titan of the Devonian
Dunkleosteus, one of the largest and fiercest predators of the Devonian period, lived around 380 million years ago. This armored fish measured up to 20 feet in length and had bony plates for teeth that acted like self-sharpening shears, capable of crushing even the hardest shells.
It was so powerful that it could devour anything in its path, making it the top predator of its ancient marine environment.
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Martha A. Lavallie
Martha is a journalist with close to a decade of experience in uncovering and reporting on the most compelling stories of our time. Passionate about staying ahead of the curve, she specializes in shedding light on trending topics and captivating global narratives. Her insightful articles have garnered acclaim, making her a trusted voice in today's dynamic media landscape.
