Some dinosaurs may have been able to match the fastest speed recorded by a human sprinter, a new study of a fossil trackway suggests. Since these footprints are frozen both in mud and time we don't know if the dinosaur in question was even pushing itself, speed-wise, but we can be pretty sure they managed it without high-tech running shoes.
Jurassic Park's “objects in the mirror” scene where the T. rex almost catches a jeep has had its scientific accuracy widely questioned (remember, the T. rex was supposedly "clocked at 32 miles an hour"), given there is debate as to whether the largest Tyrannosaurs hunted or scavenged. Nevertheless, while outrunning a T. rex might not have been too hard, at least for an athlete, there were other dinosaurs even the fastest human runners would struggle to escape.
The distance between footprints and their size and angle can be used to calculate the speed at which the animal that made them was moving. It's not a precise science, but within broad error ranges Dr Pablo Navarro Lorbés of Universidad de La Rioja has published estimates in Scientific Reports of the velocity required to make a pair of tracks found at Umbria de la Torree, Spain. At up to 44.6 kilometers per hour (27.7 miles per hour), one of these is a candidate for the fastest dinosaur tracks ever found.
For comparison, the fastest human footspeed record was set by Olympic sprinter Usain Bolt at 44.72 km/h (27.78 mph) in 2009. So human supremacy is at least possible. The dinosaur tracks, however, indicate this wasn't their top speed.
As the paper notes, it's harder to establish speeds for dinosaurs than some other extinct animals, since there aren't close bipedal counterparts today. Flightless birds have very different body designs and diets, for example. Where we do find theropod footprints, most appear to be made while walking. Unsurprising since even the fastest land animals today usually only run in short bursts.
Occasionally however we get lucky, such as with two tracks 30 meters (98 feet) apart known as La Torre 6A-14 and La Torre 6B-1. Both date to the early Cretaceous and were made by medium-sized theropods, quite likely of the same species. Identifying what that species was was impossible with the information we have, but the spinosaurid or carcharodontosaurid families are suspected.
The 6A-14 tracks were made by a larger animal, running at somewhere between 23.4 and 37.1 km/h (14.5-23.1 mph). This might be a difficult speed for a couch potato to manage, and certainly few people could maintain it for long. However, at the lower end of the estimate range reasonably fit people might manage it over the distance required to hopefully make a predator lose interest.
Getting away from the maker of 6B-1 would be more challenging, however. The average stride was 5.6 meters (18 feet) which, in combination with the length of the footprints and the estimated hip height gives a speed range of 31.7-44.6 km/h (19.7-27.7 mph)
These estimates overlap with the records of 38.9-49.7 and 33.8- 42.8 km/h for two trackways in Utah and Texas respectively.
Besides the fact the makers of these tracks were probably not champions who trained regularly for glory, there is also reason to suspect they could do better. The dinosaur that made 6A-14, for example, was accelerating over the course of the prints we have, so could have been going considerably faster a few steps later where the prints have been lost in time. For 6B-1 Navarro Lorbés and co-authors based their analysis off the first six prints, since the last one's positioning suggests the dinosaur was turning quite sharply left, which might not have been possible for a creature running flat out.
The paper also includes past estimates of theoretical maximum dinosaur speeds based both on other trackways, and on certain species' body shapes. In some cases, these produce estimates of considerably greater speed, such as for young T. rexes, but different teams sometimes produce wildly different figures, for example regarding velociraptors, casting doubt on the methodology.