358 million years ago, an armor-plated monster stalked the world's oceans. Dunkleosteus had sharp bone blades and could create a suction zone with its mouth, trapping any prey unlucky enough to come across its path. Studies suggest Dunkleosteus grew between a range of 13 feet and a staggering 33 feet in length.

Dunkleosteus fossils are immediately identifiable from the remains of their armor: a complex puzzle made of interlocking pieces that protected the animal from other underwater predators. With this extreme armor and their outrageous bite force, the Dunkleosteus was a near-unstoppable apex predator.

This pin captures the over 350,000,000-year-old Dunkleosteus as it looked in life! Want to collect a real piece of a Dunkleosteus fossil too? Check out our specimen here!

For millions of years, the true monster of the sea was not shark, nor squid, nor killer whale, but a living tank that crushed its prey with jaws like a bear trap. With its enormous, hinged mouth, this fish chased down prehistoric ammonites and easily cracked their shells open. There was no defense against the sheer might of the Dunkleosteus. It was a true apex predator that ruled over the Devonian Period’s ancient seas.

Sporting externalized pieces of bone armor, ultra-powerful jaws, and the ability to create a suction zone to drag prey down its mouth, the Dunkleosteus was the ultimate aquatic hunter. These creatures were part of the Placodermi class, bony fish with articulated plates across their bodies like suits of armor. Dunkleosteus and its relatives were among the earliest vertebrates to have hinged jaws, a monumental tool in the evolutionary arms race that put them at the top of the food chain.

At the front of these jaws, Dunkleosteus had a pair of razor-sharp bony blades. They were not teeth, but rather an extension of the animal’s skeleton that could shred prey like a pair of scissors. The bite force on the edge of one of these bone blades was over 5,300 newtons. That is well past the 4,000 newtons it takes to crack through a human femur, meaning this fish was built to crush shells from prey like ammonites or even the armor of other placoderms.

Dunkleosteus is known today from its skull and front portions of its body. Cartilage from the fish does not fossilize well, making exact body sizes difficult to know with certainty. Just how long Dunkelosteus was remains debated, with the high-end estimates topping out at around 9 m (30 ft). However, a 2023 study was more conservative, estimating an average length of 4 m (13 ft), comparing Dunkleosteus terrelli skulls against living fish and their proportions. Some scientists have taken to calling this squatter Dunkleosteus the “chunky dunk,” but it was still one of the largest animals on Earth at the time, with jaws bigger than modern sharks

Dunkleosteus was able to rapidly open and close its mouth, fully opening its jaws in just 20 milliseconds. This was thanks to special muscles that pulled its skull and upper jaw backward while its lower jaw swung down. That lightning-fast bite even created a vacuum zone in the water that pulled food deeper
into the predator’s mouth.

With Dunkleosteus as deadly as it was, there were few predators for the fish to worry about, except maybe members of its own kind. Bite marks on some skulls appear to have been inflicted by the fangs of other Dunkleosteuses, specifically targeting the back of the skull and other chinks in the fish’s armor. These conspecific duels may have been displays of dominance, or perhaps when food was scarce the fish resorted to cannibalism.