Day #4 on our Christmas Countdown is…

Deinosuchus!

Deinosuchus: the “Terrible Crocodile”

Deinosuchus was a giant great-granddaddy of alligators (though not the biggest), and it lived in Late Cretaceous North America.

The largest Deinosuchus could grow up to about 35 feet, or 10.6 meters, in length. It was a closer relative to modern day alligators than crocodiles, and for much of its life probably lived a very similar lifestyle. They seemed to grow at about the same rate as modern crocodilians, and would continue to grow throughout their life, but few would live the 50 years it took to get to full size.

These super-sized alligators can be found in Texas and Montana, while slightly smaller Deinosuchus are more commonly found anywhere along the coast of the huge interior seaway that divided North America at this time. From as far north as Montana, along the eastern coast, to as far south as the northern tip of Mexico.

So what did such giant crocodilians eat? With broad jaws built for crushing, the imagination goes wild with ideas of the monstrous reptiles cruising just below the surface of the water upon an unsuspecting herd of plant-eating dinosaurs. Like crocodiles and wildebeest on the African savannah, these crocodilians are almost always painted in mid-strike, just before they drag the hapless hadrosaur (or occasional theropod) down to the depths.

Though this scene definitely happened at least some of the time, Deinosuchus could also eat many other things in its habitat. Especially when it hadn’t quite grown up to dinosaur-hunting size yet.

The waters it lived in were brackish, which is where fresh and saltwater meet. In these environments where all sorts of fish, ammonites, mosasaurs, sharks, and turtles both big and small. In fact, Deinosuchus had flatter teeth in the back of its jaws compared to those in front, which would have been well suited to crushing turtle shells. Bothremys was a giant turtle found with bite marks like these on its shell.

Deinosuchus gives us an excellent example of how diet and hunting habits might change over time as an animal grows older. Though it may be tempting to look at an alligator or crocodile and just replace it with Deinosuchus in our imagination, we must remember to only take such imaginings as inspiration. The starting point for our mental picture of what life could have been like for these animals.

What else might have been affected by size and age? Perhaps younger, smaller Deinosuchus were more social, or cooperated in lose gangs when the season for dinosaur-hunting came to the water’s banks? Would bigger, older Deinosuchus be the kings of their stretch of beach, where even the largest of predatory dinosaurs would keep a close eye on the surface of the water if they dared to come for the turtle’s annual breeding season?

So many questions! What are a few of your theories?

See you tomorrow for day 5 of the Critter Christmas Countdown!