CROCODILES : 2

Lineage of Supercrocs

Even though Deinosuchus appears to be a lock for the title of "largest crocodile ever," it was far from the only species of giant crocodile. In addition to Deinosuchus, many other "Supercroc" genera, most notably Sarcosuchus from North Africa and Purussaurus from South America, reached lengths of ten metres or more.

These Supercrocs were found all over the world, with specimens found in North and South America, Africa, and Asia. Supercrocs were not limited to the Mesozoic epoch; some genera thrived long after the K-T extinction, with Purussaurus becoming extinct shortly before the Ice Age began. The vast reign of the Supercrocs demonstrates crocodilians' adaptability, as even after catastrophic extinctions, these magnificent animals can still reign supreme.

Were Dinosaurs on the Menu?

To answer the million-dollar question, we must first understand Deinosuchus' paleoecology. Deinosuchus lived in what is now the United States during the late Cretaceous period, as previously stated. During the Cretaceous period, North America was divided into three distinct landmasses by a shallow inland sea that covered most of modern-day America's Midwest and the areas that would become the Canadian prairies. The western landmass known as Laramidia was teeming with dinosaur species in abundance. Appalachia, the eastern landmass, still had dinosaurs, but far fewer than Laramidia. Deinosuchus fossils are common across both landmasses, indicating that they were able to migrate across the open ocean in a manner similar to modern saltwater crocodiles. While their presence on both landmasses suggests that they occasionally venture into deeper waters, there is one significant difference between the eastern and western Deinosuchus: their diets.

The eastern species of Deinosuchus is known as D.rugosus, and it can be described as a light weight (relatively speaking, of course). D.rugosus was a smaller Deinosuchus, reaching a maximum length of around 8 metres and first appearing in the fossil record around 82 million years ago. Deinosuchus riograndensis, the western species, was the true giant.

D.riograndensis is a 12-meter-long Deinosuchus that evolved about seven million years after

D.rugosus, which first appeared 75 million years ago in what is now Texas. The vast size difference between the two species must have resulted from some environmental factor within their respective landmasses. One simple explanation for their disparity is what they ate.

As previously stated, the dinosaur population in the east was small in comparison to that in the west. To survive, a large crocodile would have had to prey on the food that was readily available. In the case of Deinosuchus, this meant preying on both large fish and common turtles. These turtle attacks are documented in the fossil record, as shells in the east are routinely found with bite marks from a large crocodile, sometimes completely shattered. With this in mind, it is clear that these eastern Deinosuchus likely ate a diverse range of foods, much like modern alligators. The lack of consistent, large prey prevented them from growing larger than 8 metres in length, preventing them from becoming massive.

Their western counterparts, on the other hand, had no such problems. Deinosuchus would have shared the estuaries and river systems with large herds of Hadrosaurids and Ceratopsians. Because there was plenty of dinosaur prey available, it is thought that the western Deinosuchus populations specialised in hunting large dinosaurs. This theory is supported by the larger size of western populations due to larger and more readily available prey, as well as the discovery of Hadrosaurid bones with evidence of a crocodile attack. When the bone injuries were placed alongside Deinosuchus teeth, it provided concrete evidence of a predator-prey relationship between the two species. Some have declared Deinosuchus the top predator of its western habitats, defeating and possibly eating large carnivorous dinosaurs. In either case, Deinosuchus would have been a terrifying foe for any dinosaur unlucky enough to cross its path.

Based on the evidence presented, it appears that Deinosuchus did consume dinosaurs. Deinosuchus thrived in the shallow seas of North America for 10 million years, only dying when the waterways it called home receded. While other Supercrocs may pursue it, only Deinosuchus can claim the title of dinosaur-eating alligator.