A computer model shows that T-Rex did not have enough muscle to allow an animal of its size to run fast
By Tamara Traubman, Haaretz, Walla System
The Tyrannosaurus Rex, the "T-Rex", is known as the largest and most dangerous predator that walked the earth during the age of the dinosaurs. The T-Rex, which became extinct about 65 million years ago, left its mark on the prehistoric world, and the animals that were caught in its environment had no chance against its sharp teeth, which are about 16 centimeters long. However, scientists have now discovered that the fearsome creature did not have superiority in all areas. Contrary to popular belief, the clumsy T-Rex was probably unable to run.
The reason for this is that the amount of muscle in the T-Rex's legs was too small to allow an animal of its size to generate the power necessary for fast running. "A speed of 72 km/h, as some paleontologists once suggested, is clearly out of the question," said Dr. John Hatchinson in a telephone interview from his office at Stanford University.
Dr. Hatchinson, who studies the evolution of anatomy and movement, carried out the research together with Mariono Garcia, a computer scientist from Cornell University. Their research was published yesterday in the scientific journal "Nature".
Chinson explained that the amount of muscle needed for running increases steadily as body mass increases. However, when it comes to a very large body mass, the ratio is not maintained, and the necessary amount of muscles increases to an even greater extent.
The computer model on which the study was based indicates that in order for an adult T-Rex to run, its leg muscles had to make up more than 80% of its total body mass. "This is an unacceptable number," said Chinson, "it would have left very little room for the rest of his body - the skeleton, the other body muscles and the other organs."
The researchers also tested their computer model on crocodiles and chickens, two distant "relatives" of the dinosaurs. The chicken, for example, says the Chinson, runs well with its leg muscles making up only 17% of its body mass. However, if the chicken had the enormous dimensions of the T-Rex, whose weight was about 6 tons, its leg muscles would have to make up 99% of its body mass in order for it to move. "Therefore," said Hatchinson, "the explanation that the T-Rex and other giant dinosaurs were talented runners is questionable."
According to the model, the most likely possibility is that the T-Rex was unable to run at all. However, says Dr. Hatchinson, the model does not make it possible to determine exactly what the speed of his movement was. According to him, the T-Rex may have been capable of short bursts of running at a speed of about 16 km/h - which is the average speed for humans and elephants. According to Chinson, in the best, but highly unlikely case, the T-Rex might have been able to reach a speed of 40 km/h in these short runs, comparable to that of an Olympic sprinter. In any case, even according to this possibility, the tyrannosaurus rex, whose name means "the king of the tyrannical lizards", would have trailed far behind the cheetah, which was running at a speed of about 105 km/h.
However, even though its body was not designed to move quickly, scientists say, it was able to effectively hunt large animals, thanks to its long legs, which reached about 2.5 meters in length.
Dr. Kevin Padian, a paleontologist from the University of California, praised the anatomical and biomechanical analyzes the researchers did. The study, he said in his announcement, "sets benchmarks for how this type of work will have to be carried out in the future."
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One response
There are some convincing contradictions that Tyrannosaurus could run and hunt:
• One of them, the least convincing, is that no large carnivore alive today feeds on carcasses. In addition, the polar bear, for example, weighs in relation to its body size much more than the tyrannosaurus, and it manages to hunt well and run fast. If the white bear was the size of the Tyrannosaurus it would weigh about 18 tons. That is, the tyrannosaurus had to hunt to feed its body, because no carnivore of this size could hunt carrion.
• Another, more convincing contradiction is that the teeth of the tyrannosaurus, in all its fossilized skeletons were found to be worn, its teeth could not have been worn from eating carrion, so it is quite clear that it hunted. Fresh meat could easily wear down his teeth, but the tender flesh of the carcass could not.
• The most compelling contradiction shows that Tyrannosaurus could run faster than its hair. The computerized model showed that in order for the tyrannosaurus to run and turn quickly, the mass of its legs had to be about 85% of its body mass, which is impossible, so it is clear that the tyrannosaurus could not run. But if you look at mammals today, whose body bones are not hollow and whose weight is much greater in relation to their body size, the conclusions are completely different. The elephant, for example, weighs about 5 tons, with its body much lower and shorter than that of the tyrannosaurus, however, the elephant reaches speeds of 40 km/h and can turn faster than the models show that the tyrannosaurus turned. The hippopotamus also weighs a lot in relation to the size of its body, its weight reaches 4 tons And its body is short and very low compared to the Tyrannosaurus, the hippopotamus runs at a speed of 50 km/h.
It is clear that the tyrannosaurus could not run as fast as the hippopotamus, because its head was very heavy and only the large tail balanced it, this fact reduces its speed rate. The tyrannosaurus probably ran at a speed of 30-45 km/h and could turn 90 degrees in a second. Such a speed is sufficient to hunt large herbivorous dinosaurs such as the triceratops or duck-billed dinosaurs such as the Edmontosaurus that also ran at a similar speed.