According to new calculations by Dutch paleontologists, T. rex would have traveled just under 3 miles in an hour – a speed comparable to that of humans and many other animals – at its preferred walking speed. However, this pace is slower than other estimates of the tyrant lizard king’s walking speed.
When they have no reason to run, most animals – including humans – have a natural walking speed that minimizes the amount of body energy they expend.
Previous estimates had not fully taken into account the role of the T. rex’s tail – which makes up more than half its length – in crunching the numbers, said Pasha van Bijlert, lead actor. author of a new study on T. rex locomotion published in the journal Royal Society Open Science on Tuesday.
“Animals prefer walking speeds where, for a certain distance, energy costs are minimal. They do this by choosing specific walking rhythms that resonate their body parts. Because the entire tail of T. rex is hung on bands, which act like rubber bands. we reconstructed this tail to investigate at what step rhythm the tail of T. rex would resonate, ” says van Bijlert, a graduate student of paleobiomechanics. at VU University Amsterdam, via email.
“The whole tail, by our reconstruction at nearly 1,000 pounds, was really just a mass supported by a rubber band and it bounced slightly up and down with each step. With the right rhythm, you get a lot of movement for very little effort.”
The research team calculated a step rhythm based on a computer model of a T. rex tail, based on Trix, an adult T. rex fossil 12 meters long (39 feet long) at the back. Naturalis Biodiversity Center, a natural history museum and research center in the Netherlands. The scientists then multiplied the stride rhythm by the stride length found in fossilized tracks for an estimated walking speed of 2.86 miles per hour.
Other methods, van Bijlert said, mainly focus on calculations based on the legs and hips. They certainly play a critical role in estimates, but calculations based only on these parts of the dinosaur anatomy can lead to inaccurate Results. That’s because T. rex and many other dinosaurs had unique tails not found in other living animals today.
Comparable to the walking speed of animals today
Understanding how an apex predator like T. rex moved can help paleontologists better understand the behavior of dinosaurs and ancient ecosystems, by answering questions such as, How much food did it take to move that massive body at that speed? How far would it have been to find prey?
For example, a T. rex would use its preferred walking speed when walking to a water source, van Bijlert said. “It can also give you an idea of the distances it can travel when looking for food.”
He did not estimate the maximum speed of the T. rex in this study, but plans to do so using the same method in the future.
John Hutchinson, a professor of evolutionary biomechanics at the Royal Veterinary College in London, said the role of tails has been a neglected topic in dinosaur locomotion studies.
“At what speed giant tyrannosaurs have normally walked has not been a big question for many studies, but it is still an interesting question. The approach used here is complementary to fancier muscle-based simulation studies and, in a sense, to fossil footprint data. , ”he said in an email.
“This study cleverly covers new territory with an original model. It is interesting and would be useful to integrate and compare with other approaches in the future.”
What surprised van Bijlert most about the study was that the T. rex walking speed the team discovered was comparable to that of a wide variety of animals living today.
Humans, ostriches, horses, elephants, giraffes, wildebeest and gazelles all have a remarkably narrow distribution in preferred speeds (about 2.2-3.1 mph). big animals, ”he said via email.
“Interestingly, our new method predicts slower walking speeds for T. rex than other methods, but the speed we find is closer to that of many animals living today.”