Allosaurus Devoured Dinosaurs like a Falcon: It Didn't Eat like a T. Rex

If you were a dinosaur, you definitely wouldn't want to mess with the Allosaurus. The smaller cousin of the massive T. rex, the Allosaurus was a dexterous hunter. Now, researchers have found that this dinosaur tugged at its prey's flesh like a modern-day falcon in order to eat it-that's an unpleasant way to die.

"Apparently one size doesn't fit all when it comes to dinosaur feeding styles," said Eric Snively, Ohio University paleontologist. "Many people think of Allosaurus as a smaller and earlier version of T. rex, but our engineering analyses show that they were very different predators."

Allosaurus roamed the earth about 150 million years ago during the late Jurassic period. Walking on two legs like the T. rex, it possessed dozens of large, sharp death and averaged about 28 feet in length. While some paleontologists believe that these dinosaurs hunted in packs, rather like wolves, others believe that they were aggressive toward each other and instead hunted alone. What did they hunt? They probably went after dinosaurs like the stegosaurus.

Yet in order to find out exactly how this predator might have hunted, researchers decided to examine the movements of this dinosaur on a computer. They used a high-resolution cast of the dinosaur's skull and then CT-scanned the bones. This produced digital data that the researchers could manipulate in the computer. They ran sophisticated simulations of the head and neck movements that Allosaurus made while attacking prey, stripping flesh from a carcass or even just looking around.

Before the researchers could see exactly how this dinosaur might have ripped apart a Stegosaurus, though, they first had to place flesh back on Allosaurus' virtual bones. The scientists examined modern day crocodilians and birds in order to get a sense of what the dinosaur's musculature would have been like. Then, they built in neck and jaw muscles, air sinuses, a windpipe and other soft tissues into their computer model.

So what did they find? The researchers discovered an unusually placed neck muscle which often appears to the side of the neck in most predatory dinosaurs. Yet in the Allosaurus, the muscle was located much lower in the skull. This made the dinosaur uniquely equipped to drive its head down into prey and then pull it straight back up with the neck and body. This means that, like a falcon, the dinosaur would have grabbed and torn at its prey in a "pecking" motion rather than using the side-to-side motion that T. rex employs.

 "Allosaurus, with its light head and neck, was like a skater who starts spinning with her arms tucked in," said Snively. "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."

It turns out that while T. rex was the heavyweight champion, Allosaurus was a flexible hunter that could move its head around relatively rapidly with considerable control. The findings have given paleontologists a little more insight into the behavior of these ancient creatures. Currently, the researchers are continuing to explore additional differences in dinosaur feeding styles.

The findings were published in the journal Palaeontologia Electronica.