The new biomechanical model shows Tyrannosaurus rex in an oscillating gait

Researchers in the Netherlands have created a new approach to imagining how dinosaurs were doing. Modeling a T. rex tail as a suspension bridge, scientists have formed a new idea about the animal’s walking speed. Trix, the tyrannosaurus at the Naturalis Museum in the Netherlands, probably walked slower – but with more spring in step – than expected. This is a first step towards a more realistic movement of dinosaurs.

People and animals have a preferred speed. This is partly influenced by the amount of energy required: it prefers to go at the speed at which it uses the least possible amount of energy. One way to do this is to use something called resonance.

You already know how it works: when you’re in a cradle, you can’t sway at full speed. If you want to do it properly, you have to do the right thing and swing in the swing rhythm. In other words: you have to resonate with him. And when you take a pleasant and relaxing walk, your body parts also resonate. Slightly slower walking does not require less energy: notice that it is actually harder.

This works for four-legged animals and for two-legged animals such as humans and ostriches. Pasha van Bijlert, a student of Human Movement Sciences at Vrije University in Amsterdam (VU), applied the idea of ​​an animal that went differently than anything stepping on the ground right now: Tyrannosaurus rex. These carnivorous dinosaurs not only had two legs, but also had an enormous tail that helped them move.

Like the bones in the neck, the bones in the tails are held together by ligaments. “You could compare it to a suspension bridge,” Van Bijlert explains. “A suspension bridge with a ton of muscle in it.” At each step the tail swings up and down. This means that, like the cradle, it has a natural frequency at which it resonates.

To find out what this frequency is, Van Bijlert and his professors Anne Schulp (Naturalis / Utrecht University) and Knoek van Soest (VU) built a 3D model of the Trix, Tyrannosaurus rex on display at the Dutch National Museum of Natural History, Naturalis. They added digital muscles to the famous skeleton, and on this muscle model they were able to perform biomechanical analyzes. From these, they derived the natural frequency and a preferred speed: 4.6 km / h (2.9 mph). So when Trix was walking, she was going at about the same speed as you. If you had a T. rex pet, you wouldn’t have any problems walking – at least in terms of speed.

Van Bijlert, Van Soest and Schulp published their findings in the journal Royal Society Open Science This Wednesday. “There have already been some studies that investigated the speed of dinosaurs, but they mostly looked at the legs and ignored the tail – which makes the dinosaurs so unique,” says Van Bijlert. “They usually found much higher walking speeds. The one I calculated is lower, but it’s similar to other animals.”

Provided by Naturalis Biodiversity Center