Ancient Crocodilians Killed Dinosaurs with "Death Rolls"

Ancient crocodilians killed their smaller dinosaur prey by spinning their bodies in "death rolls," a move so violent that it tore the flesh and limbs clean away, researchers say.

These new findings shed light on the way ancient reptiles interacted with their environments, according to Live Science.

Crocodilians include the largest of all reptiles alive today, the saltwater crocodile, which can reach up to 23 feet long and weigh more than 2,200 pounds.

But this carnivorous reptile pales in comparison to its ancient brethren.

Sarcosuchus from Africa and South America could reach about 37.7 feet long and weigh a whopping 17,635 pounds.

Deinosuchus from North America could reach a length of 39.3 feet and weigh more than 18,740 pounds.

Purussaurus from the Amazon basin, the most massive of all, could reach more than 42.6 feet long and at least 22,000 pounds.

Scientists studied the bite marks found on fossils and suggest, as detailed in their report in the journal Historical Biology, that Deinosuchus preyed on small duck-billed dinosaurs called hadrosaurs as well as "medium-sized" dinosaurs known as theropods, a group that includes the ferocious Tyrannosaurus rex.

Like their modern relatives, researchers believe ancient crocodilians might have used death rolls to kill their prey. This lethal move involves reptiles gripping tightly onto their prey with their mighty jaws and spinning their entire bodies to rip or tear off flesh and limbs, Live Science wrote.

Seeing as how this move necessitates substantial skull strength, researchers were skeptical. They modeled the skulls of 16 living crocodilian species and three extinct crocodilian groups to see if they could withstand the pressure, and found that the Deinosuchus and Purussaurus, at least, could.

Lead study author Ernesto Blanco notes that this attack move was probably used more by juvenile crocodilians rather than adults because their smaller, lightweight bodies would allow them to spin more easily.

"It is possible that very large specimens use other approaches for taking chunks of meat from large vertebrates," Blanco, a paleobiomechanicist at the Institute of Physics in Montevideo, Uruguay, said according to Live Science.

Scientists also added they still had uncertainties, given that "we are studying much larger crocs than any living species," Blanco added.