T. rex would have traveled just under 3 miles in an hour – a speed similar to that of humans and many other animals – at his preferred speed, according to new calculations by Dutch paleontologists. However, this pace is slower than other estimates of the walking speed of the tyrant lizard king.
When they have no reason to run, most animals – including humans – have a natural gait that minimizes the amount of energy spent.
Previous estimates did not fully take into account the role of the T. rex tail – which is more than half its length – when writing the numbers, said Pasha van Bijlert, leader author of a new study on T. rex locomotion published Tuesday in the journal Royal Society Open Science.
“Animals tend to prefer walking speeds at which, for a certain distance, the cost of energy is minimal. They do this by choosing specific gait rhythms at which parts of their body resonate. Because the entire tail of T. rex is suspended by ligaments, which behaves like rubber bands, we reconstructed this tail to investigate at what pace the T. rex tail would resonate, “said van Bijlert, a graduate student in paleo-biomechanics at VU Amsterdam University, by e-mail.
“The whole queue, through our reconstruction of almost 1,000 kilograms, was really just a table supported by a rubber band and with each step it would jump slightly up and down. At the right pace you get a lot of movement for a very small effort. ”
The research team calculated a step rhythm from a computerized model of a tail of T. rex, based on Trix, a 12-meter-long (39-meter)-long T. rex fossil adult. Naturalis Biodiversity Center, a museum of natural history and research center in the Netherlands. The scientists then multiplied the pace of the step with the length of the step found in the fossilized footprints for an estimated walking speed of 2.86 miles per hour.
Other methods, van Bijlert said, focus mainly on calculations based on legs and hips. Sure, they play a crucial role in estimates, but calculations based only on these parts of the dino anatomy can lead to inaccuracies. results. This is because T. rex and many other dinosaurs have unique tails that are not found today with other living animals.
Similar to the walking speed of today’s animals
Understanding how a top predator like T. rex has moved can help paleontologists better understand the behavior of dinosaurs and ancient ecosystems by answering questions like: How much food did it need to move that huge body at that speed? How far would it have been to find prey?
For example, a T. rex will use its preferred walking speed when going to a water source, said van Bijlert. “It can also give you an idea of the types of distances you can cover when looking for food.”
He did not estimate the maximum speed of T. rex in this research, but intends to do so using the same method in the future.
John Hutchinson, a professor of evolutionary biomechanics at Royal Veterinary College in London, said the role played by tails was a neglected subject in dinosaur locomotion studies.
“How fast could giant tyrannosaurs have gone normally was not an important question for many studies, but it is still an interesting question. The approach used here is complementary to muscle simulation studies and, in a way, fossil record data, “he said in an email.
“This study covers a new field in a smart way 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 the most about the research was that the T. rex walking speed found by the team was similar to that of a diverse range of animals alive today.
“Humans, ostriches, horses, elephants, giraffes, wildebeests and gazelles have a remarkably tight distribution at their preferred speed (about 2.2 – 3.1 mph). So it includes both two- and four-legged animals, and also both relatively small and large animals, “he said in an email.
“Interestingly, our new method predicts lower walking speeds for T. rex than other methods, but the speed we find is closer to many animals that live today.”