In today’s Spain, over 100 million years ago, dinosaurs were traveling at speeds of up to 45 kilometers per hour, according to the analysis of fossilized footprints. The results rank among the fastest running speeds of dinosaurs that were previously calculated on the basis of tracks. Who exactly once ran there remains unclear – but it was probably medium-sized predatory dinosaurs. This fits in with previous research that the largest were not the fastest.
Obviously they once trudged, walked or ran across the earth – but how exactly did the various representatives of the dinosaurs move and what speeds did they reach? Paleontology has been dealing with this question for some time. It seems clear that the two-legged dinosaurs – the theropods – were the most agile and fastest. In order to assess their performance, mostly biomechanical models were created on the basis of anatomical features of fossils. They show that some species could reach top speeds well over 50 kilometers per hour. In principle, the medium-sized representatives such as the famous velociraptors were ahead of the game, as studies show. Because with larger predatory dinosaurs like T. rex and Co, the inertia was literally a factor and they therefore probably only reached medium speeds.
Long sequences of steps in sight
In addition to assessments based on physical characteristics, there is, however, a more direct way of obtaining information about movements: The walking behavior of the animals is reflected in the characteristics of fossilized dinosaur footprints. Calculations based on foot sizes, stride lengths and other features of tracks also allow conclusions to be drawn about running speeds. When asked about the skills at the upper end of the scale, however, it is problematic that fossilized prints mostly come from animals that were walking at a leisurely pace. On the other hand, there are very few tracks of running dinosaurs. For this reason, two dinosaur tracks discovered in Spain aroused the interest of researchers working with Pablo Navarro-Lorbés from the University of La Rioja. Because even at first glance, the steps looked remarkably long compared to the size of your feet – typical for a racing track. So the team now devoted a closer examination of the two finds.
As the paleontologists report, the two traces with the names La Torre 6A-14 and La Torre 6B-1 date from 145 to 100 million years ago. The first has five footprints about 33 centimeters long, the second seven about 29 centimeters long. Three toes stand out, as is typical of theropods. According to the calculations, the first animal probably had a hip height of 1.44 meters and the second of 1.20 meters. The researchers also recorded the exact distances between the approximately 2.50 meter long steps and other features of the individual prints. As they explain, it was possible to use this information to calculate how fast the animals were traveling.
Rapid calculation results
So it was confirmed: These dinosaurs were actually running. It remains unclear to what extent they were giving their best, but the calculations show that the larger one was traveling at a speed of up to about 37 kilometers per hour and the slightly smaller one was even faster: it managed up to around 45 Kilometers per hour, emerged from the calculations. The results now rank among the top of the few calculation results based on racing tracks: They are only slightly exceeded by a few examples from North America. “These are two of the fastest speeds ever calculated for theropods, which sheds further light on the biodynamics of these animals,” the researchers write.
But who once raced through today’s Spain? Based on the characteristics of the footprints, the scientists assume that both traces come from the same predatory dinosaur species – or at least family. What exactly that was, however, remains unclear. Obviously, they were medium-sized and rather lightly built theropods. This includes candidates who, according to fossil recordings, lived in the region in the early Cretaceous period. According to Navarro-Lorbés and his colleagues, it is possible that a representative of the predatory dinosaur family of the spinosaurids or the carcharodontosaurids rushed over the once soft subsoil at the site.
Source: Scientific Reports, doi: 10.1038 / s41598-021-02557-9