A fresh look at fossil footprints suggests that long-standing equations used to calculate dinosaur speeds may be misleading. Researchers in England have tested the accuracy of these formulas with living animals and found significant differences between estimated and actual movement.
Key points include:
- A study published on June 25 in Biology Letters questions the reliability of speed calculations.
- Experiments with helmeted guinea fowl walking in mud show large discrepancies.
- The method created by zoologist Robert McNeill Alexander in the 1970s may not fully apply to dinosaurs.
Table of contents:
- Peter Falkingham and fossil tracks in England
- Guinea fowl experiments and unexpected data
- Differences between treadmill tests and natural movement
- Implications for Tyrannosaurus rex and other dinosaurs
Peter Falkingham and fossil tracks in England
Peter Falkingham, a paleobiologist at Liverpool John Moores University, led the research. He explained the work during a video call from a fossil dig near Oxford, England. Holding his phone to the ground, he showed a massive fossilized track, likely left by a sauropod. These long-necked dinosaurs, resembling giraffes in appearance, often produced footprints large enough to fit several human feet inside.
For decades, scientists relied on equations that linked stride length to speed. Robert McNeill Alexander developed these calculations by studying mammals in the 1970s. The assumption was straightforward: the longer the stride, the faster the animal. With this approach, any footprint could be turned into a speed estimate.
However, Jonathan Codd, a physiologist at the University of Manchester, notes that dinosaurs are closer to modern birds than mammals. Moreover, Alexander’s research was based on animals moving across hard, dry surfaces, not soft ground where fossilized tracks are usually found.
Guinea fowl experiments and unexpected data
Falkingham revisited videos he had recorded over 10 years ago. The footage showed helmeted guinea fowl (Numida meleagris) walking through specially prepared mud. Originally, he had filmed them to study how their feet interacted with wet ground. The mud was made with poppy seeds and glass bubbles so that X-ray imaging could capture the birds’ foot movements.
The work was difficult. Falkingham had to wash the birds’ feet after each trial and repeatedly remake the mud, which often spoiled overnight. On the final day of testing, he filmed two birds moving across the muddy surface and took detailed photographs of their tracks. At the time, these recordings were made out of curiosity. Today, they form the foundation of the new study.
When the researchers compared the birds’ actual speeds with those calculated from their footprints, the results did not match. The formula often overestimated movement by up to 2.5 times. The reason was clear: sticky ground slowed the animals, while stride length alone could not explain their pace.
Differences between treadmill tests and natural movement
Earlier work with guinea fowl running on treadmills had supported Alexander’s method. Those birds maintained steady speeds and stride lengths, creating neat data sets. The situation in mud was very different. Here, the same animal could take longer or shorter steps without changing its speed.
This revealed a flaw in applying simple equations to complex natural behavior. Falkingham emphasized that wild animals do not move mechanically. They adjust stride and pace depending on conditions, making calculations based solely on footprints unreliable.
Implications for Tyrannosaurus rex and other dinosaurs
The new findings do not provide a final answer to how fast dinosaurs could run. Instead, they highlight the uncertainty of past estimates. For Tyrannosaurus rex, calculated speeds still range widely between 20 and 40 kilometers per hour (12 to 25 miles per hour).
Jonathan Codd concludes that the exact figure may remain unknown. Without living specimens, scientists can only approximate. What the study shows clearly is that the “muddy math” of dinosaur speed is far less precise than once believed.
Source: Science News Explores, YouTube