Ancient 'terror crocodile' Deinosuchus had banana-sized teeth that took down monster dinosaurs

Alligators and crocodiles are often the stars of some pretty intense nature documentaries, but they had an ancestor that makes them look like backyard lizards.

Deinosuchus was probably not something even T. rex would want to mess with. Though it had been suspected to be a dinosaur-eater before, new research has found that this beast literally had teeth the size of bananas, and that it preyed on unsuspecting dinosaurs — that includes carnivorous therapods. Bone analysis reveals it went after some huge meals. It would lie in wait underwater until a tasty dinosaur showed up to take a drink, then drag it to its watery doom. The name Deinosuchus means “terror crocodile” for a reason.

72 to 82 million years ago, the terror croc outweighed even the largest therapods, making it the boss predator in its ecosystem and possibly the largest crocodilian ever. Back in the Late Cretaceous, there was a shallow sea flowing through the middle of North America from the Gulf of Mexico all the way to the Arctic Ocean, and it could usually be found hidden at the water’s edge.

“We have evidence of Deinosuchus bite marks on a number of fossil bones including therapods, hadrosaurs (duck-billed dinosaurs), and turtles,” paleontologist Adam Cossette, who led a study recently published in Journal of Vertebrate Paleontology, told SYFY WIRE, though he did add that “It is quite difficult to determine which species the prey happened to be, as the bones are isolated and in poor condition.”

So we may never know if Deinosuchus actually ate a T. rex, but the 33-foot monster with crushing jaws would probably have no problem with one. The marks its outsize teeth left on dinosaur bones was indicative of its ferocity (even though bite force was not an objective of the study). Deinosuchus is actually a closer relative of alligators despite its name, but since both alligators and crocodiles take apart prey with a terrifying “death roll,” that must have not mattered for the unfortunate victims. Both alligators and crocodiles are assumed to have inherited the death roll from their common ancestor. Since Deinosuchus was an ancient alligatoroid, it would have taken down dinosaurs with this grisly method.

“Its powerfully built skeleton and musculature would have been capable of producing forces that are far in excess of any modern species of crocodilian,” Cossete said. “It would have seized its prey at the water's edge, submerged it, and completed a series of death rolls until that prey was ripped into bite size pieces. Predictably, this behavior would have easily dismembered large dinosaurs.”

Deinosuchus was a mystery monster until now. Though the study exposed it as having nightmarish teeth and jaws strong enough to crush large dinosaurs, there is still much uncertainty surrounding the species. Is it even just one species? Paleontologists remain unsure, though Cossette and his team proposed that all the subspecies of Deinosuchus might actually be the same animal that may have grown larger or smaller depending on the availability and size of prey in the area it lurked.

Lateral and frontal views of the skull of Deinosuchus. It's much more terrifying in person. Credit: Adam Cossette

Another mystery stares back from its skull (above). Deinosuchus had two large holes at the tip of its snout, and while the front of its snout was critical to capturing prey and had enough bone mass to handle a dinosaur for dinner, what those holes were for is still unknown. They may have been an adaptation to lighten all that bone mass. This could have actually weakened the snout, but that does not seem to be the case here.

“The prey consumed by Deinosuchus was very large. It would seem that large holes at the tip of the snout would be detrimental if those holes dramatically weakened the snout. Yet the effect of these holes does not seem to hinder Deinosuchus,” said Cossette. “An additional hypothesis is that the holes were for supporting soft tissues. However, there is no evidence in the form of accessory growths of bone or holes for nerves or blood vessels in the area.”

While some aspects of the terror crocodile remain mysterious, one thing that is almost certain is that it needs its own horror movie.