The fossilized remains of gigantic crocodiles have been discovered in the Aguja Formation in the south-central part of the Big Bend National Park. These are among the largest crocodiles ever known.

With lengths of 40-50 feet and jaws studded with 6-inch teeth, these powerful predators were extraordinarily equipped to feed upon a variety of dinosaurs. In fact, dinosaur bones have been found here that are heavily damaged and covered with distinctive crocodile bite marks! Just like modern day crocodilians, Deinosuchus riograndensis probably hunted by ambush...lying submerged near shore, and violently seizing large dinosaurs as they foraged amid the vegetation of Big Bend's ancient swamps.

The magnificent skull of Deinosuchus is on display at the Dallas Museum of Natural History.