The giant Tyrannosaurus rex was able to crush the bones of its prey thanks to prodigious bite forces and world-record tooth pressures, scientists have shown.
The ability of some carnivorous mammals to pulverise bones with their bites is known as extreme osteophagy. The behaviour has been observed in present-day hyenas and wolves.
However, reptiles, including crocodiles (dinosaurs' closest living relatives) do not have the adequate dentition to do it. They can swallow bones if they are not too large, but are unable to crush them with their teeth.
T-rex appears to have been unique among reptiles for achieving this mammal-like ability, even though it didn't have a specialised, occluding dentition. This has long intrigued scientists, and many have attempted to find out more about the dinosaur's deadly bites.
In a study now published in the journal Science Advances, researchers have come up with an explanation for how T-rex would have mastered this bone-crushing skill.
Getting more out of a meal
Previous studies looking at the prey of T-rex and at its faeces have suggested that the dinosaur could bite down the bones of other dinosaurs with great force, and that it could successfully digest bone fragments.
For this research, the team, from Florida State University, build on previous models they had designed to study how the musculature of living crocodilian species contribute to bite forces. They came up with a model for T-rex, which took into account bite forces but also tooth pressure.
Indeed, having high bite force doesn't necessarily mean an animal can puncture or pulverise bone – for this studying tooth pressure is more relevant.
The scientists also describe how the remains of a triceratops bear 80 bite marks attributed to Tyrannosaurus rex, with part of a bone appearing to have been removed by repetitive, localised biting – and this feeding behaviour was also included into their model.
They found the giant dinosaur was able to bite down on bones that with nearly 8,000 pounds of force – equivalent to the weight of three small cars – while their long teeth generated as much as 431,000 pounds per square inch of bone-failing tooth pressures. Localised biting completed the picture, allowing them to finely fragment bones.
This ability to perform extreme osteophagy might have given T-rex an advantage over other carnivorous dinosaurs that lived at the time, as they were able to exploit large dinosaur carcasses for sustenance more fully.
"When they ate their prey, such as triceratops, this ability allowed them to eat the flesh but also to get sustenance from the bones, which were rich in bone marrow and mineral salts. Compared to other carnivores, they might have gotten more energy out of their meals – and it may even have played a part in how they got this large", Gregory Erickson, one of the study's authors, told IBTimes UK.
The scientists say their model could be used in the future to study the feeding biomechanics of other dinosaurs in greater details.