It ate like a bird, according to scientists.
Allosaurus, a theropod considered to be the smaller cousin of Tyrannosaurus rex, is now thought to have devoured prey the same way a modern falcon does: by driving its head down and then pulling it back up with the neck and body.
Lead by paleontologist Eric Snively of Ohio University, a team of experts in the fields of mechanical engineering, computer visualization, and dinosaur anatomy released findings in the latest online issue of Palaeontologia Electronica that detailed their understanding of how the Allosaurus moved its head, including how it fed.
Creating a cast of the 5 foot long head and neck of the Allosaurus, the team performed a CT scan at O’Bleness Memorial Hospital in Athens and converted their data into a 3D model that they could then manipulate. Adding additions such as musculature and a windpipe to the skeletal remains, they used the engineering and robotics practice of multibody dynamics to perform motion simulations of the head in movement.
John Cotton, a study co-author and mechanical engineer, said in a statement that “The engineering approach combines all the biological data — things like where the muscle forces attach and where the joints stop motion — into a single model. We can then simulate the physics and predict what Allosaurus was actually capable of doing.”
They discovered that Allosaurus had a lighter skull and head than T. rex, giving it the advantage in speed and precision. Not only that, but a specific muscle also differentiates the two. The longissimus capitis superficialis—a neck muscle—stretches from the sides of the neck to the back of the skull in most predators. Allosaurus’s was placed lower on the skull, giving it a different set of head motions to work with.
Snively provided a more colorful comparison in a statement, equating the two dinosaurs to professional skaters. “Allosaurus, with its lighter head and neck, was like a skater who starts spinning with her arms tucked in, whereas T. rex, with its massive head and neck and heavy teeth out front, was more like the skater with her arms fully extended . . . and holding bowling balls in her hands. She and the T. rex need a lot more muscle force to get going.”
Having lived 150 million years ago during the late Jurassic period, Allosaurus’s relation to modern-day birds and crocodilians connects the study’s findings to the present. Still, the head movements are not necessarily relegated to the up and down feeding pattern of the falcon. Indeed, Snively commented that the beast’s dental arrangement suggested forceful, alternating tugs to either side of the head that recalled those of the Komodo dragon.
The researchers involved in the study will continue exploring other aspects of how different dinosaurs fed using the same unique process as applied to Allosaurus.