Biology

Computer modelling suggests that T. rex was a slow walker

Computer modelling suggests th...
The model was based on the skeleton of "Trix," an adult female Tyrannosaurus rex
The model was based on the skeleton of "Trix," an adult female Tyrannosaurus rex
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The model was based on the skeleton of "Trix," an adult female Tyrannosaurus rex
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The model was based on the skeleton of "Trix," an adult female Tyrannosaurus rex
Pasha van Bijlert with a replica of Trix
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Pasha van Bijlert with a replica of Trix

All walking animals have something in common – their preferred walking speed is largely determined by what's known as "resonance." Bearing this in mind, Dutch scientists have calculated what may have been the default walking speed of Tyrannosaurus rex.

As an animal strides forward, the location of its body's center of mass likewise rhythmically moves back and forth. In order to expend as little energy as possible, most creatures match their pace to that rhythm, the latter of which is determined by factors such as the distribution of weight to different parts of the body.

This unconscious synchronizing of walking speed with mass-shifting-rhythm is called resonance, and it's the reason why walking at your regular pace is actually easier than walking at an unusually slow speed. Working with Prof. Knoek van Soest from Vrije Universiteit Amsterdam – along with Prof. Anne Schulp from Utrecht University – Vrije human movement sciences student Pasha van Bijlert set out to determine the speed at which resonance would occur for a T. rex.

In order to do so, the scientists created a 3D computer model based on the skeleton of an adult female Tyrannosaurus rex currently on display at the Dutch National Museum of Natural History. Not only did they digitally add muscles and organs to its main body, but they also allowed for the suspension-bridge-like swaying of its huge muscular tail, which would have swung back and forth with every step.

Pasha van Bijlert with a replica of Trix
Pasha van Bijlert with a replica of Trix

Based on the team's biomechanical analysis, it was estimated that the animal would have preferred to walk at a speed of 4.6 km/h (2.9 mph). This is actually close to the preferred walking speed of adult humans, which sits at about 5 km/h (3.1 mph).

"There were already some studies investigating dinosaur walking speed, but they mostly looked at the legs and ignored the tail – which is what makes dinos so unique," says Van Bijlert. "They usually found much higher walking speeds. The one we calculated is lower, but it's similar to that of other animals."

A paper on the research was recently published in the journal Royal Society Open Science. And in an interesting side note, a 2020 North American study likewise determined that based on its anatomy, T. rex was likely designed more to walk than to run.

Source: Naturalis Biodiversity Center via EurekAlert

8 comments
Mark Mac
Science always under estimates animals before it was that they stood up straight maybe t rex did just walk over and take control of a kill but if she was any thing like a chicken I think she was up to running.
Mark Mac
If it walks like chicken it's probably a chicken maybe it did just walk over and take control Of the kill but that body was made for than just walking ,lately all these people looking for fame come out with crazy idea looking for look at me.
Daishi
They offer an animation on their website and their point is the body of the T-Rex the most efficient resonant walking speed would have been walking slowly and that is where it consumes the last amount of energy. I think that's a valid point but what we don't and can't know is how lazy T-Rex was and how much time it spent moving that slowly to conserve energy. Many creatures are able to move slowly and conserve less energy but be fast when they need to be.
Rumata
This is not science, but just a bad joke.

They based their theory on a mechanical model of the tail that is totally wrong.
As a matter of fact, there are no "springs", just muscles in the tail.
Hence, there can be no "natural frequency" or "resonance" in the tail.

Shame of you, Vrije Universiteit Amsterdam.

Even a kid can see, that T-Rex has a "runner" anatomy, as opposed to a "walking" body of an elephant.
Hence, we can be sure, that T-Rex could walk and run much faster, then elephants would.

So please, don't say stupid things.
Douglas Rogers
Aren't there already tracks that reveal this?
WB
Rumata..you can do better. Don't be a d!ck. Show some respect. You are way out of line and know nothing. Stop being ignorant
Ralf Biernacki
A lion, wolf, or a cheetah also normally walks slowly, conserving energy. But it can run like a bat out of hell when it needs to, the natural frequency of its walk be damned. So could T.rex, I suppose ;-) @Rumata: there are no springs in a pendulum. No muscles, either. But it totally does have a natural resonant frequency, and so does the tail which while more complex is also essentially a swinging mass. Not that I am very impressed with the mechanical model in the paper: it makes too many arbitrary assumptions and simplifications, and essentially ignores everything but the tail. Still, it is a more refined approach than what a kid can see. So please, don't say stupid things.
styly1
Remember when all the "experts" where positive dinosaurs dragged their tails round like ropes behind them? To my mind these types of dino hopped at speed and walked sometimes . Small arms, large powerful legs and counter balancing tail. It is the equivalent of a Jurassic kangaroo is it not? Take a look at the black bird in your garden.