Researchers are developing a methodology that uses AI to help dinosaur species responsible for each footprint.

An archaeologist stands next to a dinosaur footprint.

From footprint to dinosaur identity.. AI brings scientists closer to solving a persistent mystery.

Footprints are among the most common types of dinosaur fossils. Scientists sometimes find a single, isolated footprint, and other times they come across scattered, irregular tracks resembling dinosaurs leaping around in a ballroom. 

However, identifying which dinosaur left which footprint remains extremely difficult. Researchers are now developing a methodology that uses artificial intelligence to help identify the dinosaur species responsible for each footprint based on eight different characteristics of the footprints.

"This is important because it provides an objective method for classifying and comparing footprints, reducing reliance on subjective human interpretation," said physicist Gregor Hartmann of the Helmholtz Centre for Advanced Study in Berlin, Germany. Hartmann is the lead author of the research published in the journal Proceedings of the National Academy of Sciences, according to Reuters. 

“Matching a footprint to its maker is a huge challenge, and paleontologists have been debating this for generations,” added Steve Brosett, a paleontologist at the University of Edinburgh. Dinosaurs left behind a wide variety of fossilized remains, including bones, teeth, claws, skin flakes, feces, vomit, undigested stomach contents, eggshells, and nest fragments.

These features include the overall load and shape, which reflect the contact area of ​​the foot with the ground, the loading position, the spread of the toes, how the toes are attached to the foot, the position of the heel, the loading of the heel, the relative focus of the toes versus the heel, and the difference in shape between the right and left sides of the footprint.

A Cinderella-style footprint matching: Experts had already identified, with a high degree of confidence, many footprints belonging to specific dinosaur species. 

After the algorithm identified the distinguishing features, the experts created a diagram showing how they matched the different types of dinosaurs believed to have left those footprints, to guide future footprint identification. Hartman said, "The problem is that identifying the dinosaur that left a fossilized footprint is inherently uncertain."

He added: “The shape of the footprint depends on many factors beyond the animal itself, including what the dinosaur was doing at the time—walking, running, jumping, or even swimming—the humidity and type of substrate (ground surface), how the sediment buried the footprint, and how the footprint has changed due to erosion over millions of years. As a result, the same dinosaur may leave footprints that look very different.”

Dinosaur footprints also come in a variety of sizes. “The difference in size can be quite large,” said Bruzzette, “ranging from the footprints of small, carnivorous dinosaurs the size of chickens in a coop to the footprints of long-necked dinosaurs the size of a bathtub.” Bruzzette said he could only recall one instance where a paleontologist found a dinosaur skeleton at the end of a track left by the animal.

“This means that if we find footprints, we have to play detective and determine which dinosaur left them,” Bruzzette added. “To do this, we’re doing what the prince did in Cinderella when he matched Cinderella’s foot to the shoe—we’re trying to find a dinosaur foot that matches the footprint.”

One of the algorithm’s most interesting conclusions relates to images it examined of seven small, three-toed footprints from South Africa, dating back approximately 210 million years. 

The conclusion confirmed a previous assessment by scientists that these footprints closely resemble those of birds, even though they are 60 million years older than the oldest known bird fossils. Theories suggest that birds evolved from small, feathered, bipedal dinosaurs.

“This doesn’t, of course, prove that they were made by birds,” Bruzzette said of the footprints. He noted that they could have been made by previously unknown ancestors of birds or by dinosaurs unrelated to birds but with bird-like feet. Brouzette added: "Therefore, we must take this matter seriously and find an explanation for it."