Fossilized footprints in Mongolia

Fossilized footprints found in Mongolia have changed how scientists view dinosaur movement. A medium-sized theropod dinosaur was running at 45 kilometers per hour 120 million years ago, setting a new speed record for the Cretaceous period.

Two distinct tracks discovered

Scientists uncovered two different sets of tracks in Cretaceous sediments in Mongolia, dated between 130 and 120 million years ago. The first track was likely made by a large theropod called Chapus lockleyi, which was walking slowly.

Evidence of a sprint

The second set of tracks, made by a medium-sized dinosaur from the Eubrontidae family, showed signs of a fast sprint. Researchers used the distance between footprints to estimate the dinosaur’s speed, revealing it could reach up to 45 kilometers per hour.

Calculating dinosaur speed

To estimate the speed of extinct animals, scientists use the size of the footprints and the distance between steps to calculate stride length. A key formula involves dividing the stride length by the dinosaur’s hip height, which helps determine if it was walking, trotting, or running.

Size and speed relationship

This discovery highlights that dinosaur size influenced their speed. Large theropods, weighing over 1000 kilograms, moved slowly due to their massive bodies. In contrast, smaller and medium-sized theropods had a better power-to-weight ratio, allowing them to run faster.

Confirming biomechanical models

The Mongolian footprints provide real-world evidence supporting computer models that predicted these dinosaurs could run quickly. The findings, published in Science China Earth Sciences, show that these ancient predators had agility and speed similar to modern mammals.