It’s almost unfair. Carnivorous dinosaurs had powerful teeth embedded in muscular jaws, wielded dangerous claws on their hands and feet, and had keen eyesight and smell. And on top of that, a new study now confirms that some of them were also extremely fast.
Two fossilized footprints from about 120 million years ago in the Cretaceous period, discovered in the La Rioja region of northern Spain, show that the medium-sized carnivorous dinosaurs that left the footprints were able to run the fence. 45 km/h, scientists said on Thursday (9).
It’s roughly the maximum speed reached by Jamaican sprinter Usain Bolt, the fastest human being in the world.
Two tracks were found, more or less 20 meters apart. One of the tracks has seven footprints, the other has five.
Each footprint — a paw print with three clawed fingers — measures about a foot in length.
The footprints were left on the muddy surface of a lake plain in a region also inhabited by long-necked herbivorous dinosaurs, bipedal herbivorous dinosaurs, flying reptiles known as pterosaurs, crocodiles and turtles.
Speed was one more weapon in the arsenal of carnivorous dinosaurs as the species that left footprints in Spain.
“Their ability to run very fast and maneuver certainly allowed them to hunt their prey very effectively. And of course I wouldn’t want to be caught by an animal like this on a riverbank,” commented doctoral student in paleontology Pablo Navarro-Lorbes , from the University of La Rioja and the main author of the research published in the journal Scientific Reports.
The footprints show features showing that they were made by a theropod, a group that encompasses all carnivorous dinosaurs, including Tyrannosaurus rex. Theropods were bipedal. The largest of them measured something like 15 meters in length.
The researchers believe the tracks were left by two different individuals of the same species. They suspect the individuals were from one of two families of theropods: spinosaurs, many of which were fish-eating, or carcharodontosaurs, known for their shark-like teeth. The individuals were about four to five meters long and two meters tall and weighed between 200 kg and 300 kg.
The dinosaurs’ running speed was calculated based on the relationship between the animal’s hip height (estimated from its footprint length) and its stride length. The step length of one of the tracks was 5.5 meters and the other 5.2 meters.
One of the dinosaurs ran at between 31.7 km/h and 44.6 km/h, one of the fastest speeds ever estimated by a dinosaur, and the other at between 23.4 km/h and 37.1 km/h. A trail indicates that the animal has been gaining speed smoothly. The other suggests an animal that was maneuvering while running.
Angelica Torices, a paleontologist at the University of La Rioja and co-author of the study, said the speed helped dinosaurs not only hunt, but flee from danger, including “larger theropods that could stare at them as prey.”
Among the countless dinosaur tracks found around the world, almost all are from animals that were walking, not running. The highest running speed estimated from footprints was a Jurassic period theropod trail found in Utah: 55 km/h.
Scientists also calculate dinosaur displacement speed based on biomechanical models. With this method, the fastest found was the theropod Compsognathus, from the Jurassic period and with the size of a turkey, which reached 65 km/h.
“There are several factors that dictate a dinosaur’s ability to run,” said Navarro-Lorbes.
“One is size. Some paleontologists think that theropods weighing between 100 kg and 1,000 kg may have been some of the best runners among dinosaurs because of the relationship between their weight and their muscle performance,” said Navarro-Lorbes. Another key factor would be your long legs.
Translation by Clara Allain
.
