Biology

Running not an option for Tyrannosaurus rex

Running not an option for Tyra...
New computer modeling claims that the T. rex wouldn't have been able to run due to its size and weight
New computer modeling claims that the T. rex wouldn't have been able to run due to its size and weight
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New computer modeling claims that the T. rex wouldn't have been able to run due to its size and weight
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New computer modeling claims that the T. rex wouldn't have been able to run due to its size and weight

In good news for anyone coming face to face with a Tyrannosaurus rex, a new study indicates that humans could outrun the fearsome dinosaur. By combining two separate biomechanical computer simulations, scientists at the University of Manchester have concluded that running would have been out of the question, and even the giant meat eater's walking speed would have been limited due to its size and weight.

The Tyrannosaurus rex is one of a handful of dinosaurs whose name is instantly recognizable. One of the largest predators to ever walk the Earth, the huge bipedal reptile lived during the Upper Cretaceous Period roughly 65 million years ago and grew up to 12.3 m (40 ft) in length and 3.66 m (12 ft) tall at the hips, with a weight between 8.4 to 14 tonnes (9.3 tons to 15.4 tons). It also had a set of serrated teeth and a bite that could exert about 8,000 lbf (35,586 N).

But despite being the center of intense study for over a century, there are still many unanswered questions surrounding the T. rex. One of the most important is how fast could it move? Over the years, there have been many attempts to estimate how fast the dinosaur could get around, with some studies suggesting speeds of up to 45 mph (72 km/h). Since even a horse can only do around 30 mph (48 km/h), a running human wouldn't have stood much of a chance if T. rex was still alive today and capable of such speeds.

But to obtain a more accurate assessment of a T. rex's speed, a team of scientists led by Professor William Sellers of the University of Manchester's School of Earth and Environmental Sciences looked at the gait and biomechanics of the dinosaur using a new computer simulation model. The model was developed by combining two separate biomechanical techniques called MultiBody Dynamic Analysis (MBDA) and Skeletal Stress Analysis (SSA).

By creating a simplified model of the T. rex's skeleton and muscles, the team figured out not only how such a massive biped could run, but also the load stresses that moving that fast would put on the skeleton, especially the leg bones.

They found that though a young T. rex could move relatively fast, by the time it reached adulthood, the stresses placed on the legs would have been so great that anything faster than a walking pace would have caused the bones to buckle. Needless to say, this meant that running was out of the question and the researchers say it would have limited the dinosaur's top speed to around 27 km/h (17 mph).

According to Sellers, the findings have implications beyond a new trivia fact to annoy fans of Jurassic Park. It explains why no running T. rex footprints have been found and will help paleontologists figure out what the dinosaur hunted and how it caught its prey. In addition, the technique can also be used on other large two-legged dinosaurs, including Giganotosaurus, Mapusaurus, and Acrocanthosaurus.

"Tyrannosaurus rex is one of the largest bipedal animals to have ever evolved and walked the Earth," says Sellers. "So it represents a useful model for understanding the biomechanics of other similar animals. Therefore, these finding may well translate to other long-limbed giants so but this idea should be tested alongside experimental validation work on other bipedal species."

The research was published in PeerJ (PDF).

The video below shows one of the T. rex simulations.

T-Rex movement

Source: University of Manchester

7 comments
Bob Stuart
I've been waiting for this ever since J.E. Gordon pointed out that Elephants can run but not jump.
owlbeyou
A close look at this beast tells us that it's one top-heavy giant. The speed capability that Sellers et al have calculated is realistic enough, but that is on level and relatively smooth terrain. Once things get choppy, this animal ain't gonna run without the risk of falling becoming a serious limit. Can you imagine T Rex taking a nose dive? Those little forearms aren't gonna help much. And who was slow enough for lunch? The slowest of the herbivores maybe, or those who've been hurt. Old age couldn't have been kind to dinosaurs, hunter or prey. Seems like T Rex may have had to use a kind of surprise tactic to get its meal.
Bob
Just about every large animal can run 30 mph for a short distance whether it is an elephant, bear or alligator. 17 mph sounds rather slow but faster than the average human. But even a track star isn't going to run faster than 17 mph for very far.
Tanstar
A quick Google search shows human top speed at 28 mph, but that the average person can only run at 10-15 mph. Bolt is safe, but the rest of us may get eaten still. Granted, only if you let him get close . . .
Rustgecko
The T.rex could have been primarily a scavenger, or attacking injured or slow moving but large herbivores.
twoartistic
Watching the video, there is a basic flaw in the load analysis. There is no apparent compensation for the flexibility of the spine. It was wondered for years how cats can land from a great heights without injury. High speed photography, reveled the energy absorption of a cats skeleton and body mechanics. I am not suggesting T-Rex was cat like, but greater regards for skeletal flex and body mechanics need to be accounted for in the model. Isolating leg dynamics attached to a rigid mass is fundamentally flawed.
Rumata
This "simulation" is a very unprofessional, useless crap. It is clear, that the "scientists" know nothing about basic anatomy. For any simulation, it is obligatory to do a "reality check". If it is known, that even herbivore elephants can run with 25mph, then how can anybody state that the carnivore T-Rex of similar size can run only with 17 mph? When comparing the leg of elephant with the leg of T-Rex, it is obvious, that while elephant was made for walking, T-Rex were made for running. Why T-Rex would need running feet, if they can only walk? Twoartistic has the point. The very amateur simulation was made with an extremely oversimplificated rigid spine and neck model. This can easily explain why they received unrealistic peak forces from the simulation. With rigid spine and neck, even a horse could not run. Considering their leg and tail structure, T.rex should be very speedy runner, and also very good jumper. Especially, when compared to elephants :-)