T. Rex couldn’t run, new study finds

While movies such as Jurassic Park would have you believe that a Tyrannosaurus rex would be capable of chasing down its prey at high speeds, new research published this week in the journal PeerJ has revealed that the massive predator could manage a top speed of just 12 mph.

In their study, William Sellers, a professor at the University of Manchester School of Earth and Environmental Sciences, and his colleagues explained that the enormous carnivore was too large and too heavy to have traveled faster than 5.4 meters per second (12 mph) without collapsing.

While that’s about the equivalent of a brisk walk, as Gizmodo pointed out, the T. rex would still have been able to overtake most humans, as the typical person can sprint at speeds of between 8 and 15 mph, with only elite athletes capable of reaching velocities in the 20 mph range.

Sellers and his colleagues conducted an in-depth analysis of T. rex biomechanics, combining two different techniques – multi-body dynamic analysis (MBDA) and skeletal stress analysis (SSA) – and combining them into a single simulation model for improved accuracy. They discovered that the creature’s leg bones would have buckled under their own weight at higher speeds.

Predator would have still to be faster than its potential prey

Running gaits, the professor explained in a statement, would have resulted in “unacceptably high skeletal loads” and, most likely, in broken legs for the sprinting predator. The new study counters previous research suggesting that the T. rex was capable of running at speeds of up to 45 mph.

“Different studies using differing methodologies have produced a very wide range of top speed estimates,” Sellers noted. However, by utilizing “a new approach that combines two separate biomechanical techniques,” his team established that “true running gaits would probably lead to unacceptably high skeletal loads in T. rex,” he added.

Paleontologists had never combined MBDA and SSA to study the biomechanical properties of an animal before, Gizmodo said, and the new method allowed them to account for the amount of pressure that bones can manage before breaking. The new simulations calculated all of the forces in the limb bones of the T. rex to see what type of speed and impact that they could handle.

In addition to determining that the T. rex was far slower than some studies have suggested, the study authors concluded that the creature walked briskly in a “bird-like” manner. Even so, as the website noted, it still would have been more than capable of tracking down prey, as nearly all of the herbivores present in its environment would have traveled at much slower speeds.

“Our previous simulations of theropod bi-pedal running did not directly consider the skeletal loading but these new simulations do calculate all the forces in the limb bones and these can be used directly to estimate the bone loading on impact,” Sellers said. “It would be very valuable not only to investigate the gait of other species but also apply our multiphysics approach to different growth stages within that species.”


Image credit: University of Manchester