Amsterdam, Netherlands – Tyrannosaurus Rex was a fearsome hunter, but when it came to walking, the dinosaur probably roamed the Earth at a more leisurely pace.

According to anatomical analyses, Dutch researchers calculated the normal walking speed of the giants at about 4.2 feet per second – the equivalent of 2.86 miles per hour.

For comparison, the average walking speed of humans is about 4.4 to 4.67 feet per second, which is 2.98 to 3.17 miles per hour.

The normal walking speed can generally be determined in animals by looking at the body parts involved, their natural rhythms given the overall structure, and their need to conserve energy, according to Pasha van Bijlert's team at the University of Amsterdam. The findings were published in the scientific journal Royal Society Open Science.

In the case of the T-rex, which could grow up to 42.7 feet long and weighed 9 tons and walked on two legs, walking involved mainly the two legs and the tail. It would raise and lower its tail with each step to keep balance.

With the help of a 3D reconstruction and a biomechanical model of the species' skeleton structure, the Dutch researchers estimated the natural frequency at which the tail would swing. They assumed a hip height of 10.2 feet and a stride length of 6.4 feet.

A speed of 4.2 feet per second is lower than previous estimates, the authors write. But they do note that this is just the normal walking speed of the T-rex, not its top speed.

Earlier studies had shown that the predator barely reached 18.64 miles per hour while running. By comparison, Usain Bolt, the fastest man alive, sprinted at an average speed of about 23.2 miles per hour over 100 meters in his career.