Fossils in Ancient Seabed Show Signs of Turtle Stampede

Scientists say they may have discovered evidence of a prehistoric turtle stampede on a remote Italian cliff. The story begins in 2019, when rock climbers, venturing into a dangerous, off-limits section of limestone cliffs above the Adriatic near Ancona, Italy, found thousands of odd, crescent-shaped impressions in the rock—remnants of an ancient seabed—appearing in pairs alongside round divots. Geologist Alessandro Montanari concluded that the marks were left by fins moving along the seafloor, which narrowed it down to three types of reptiles—mosasaurs, plesiosaurs, and sea turtles, reports the New York Times. Because only turtles are likely to travel in large groups, Montanari's team deduced they were left by turtles.

In a study published in Cretaceous Research, Montanari and fellow researchers suggested the impressions were likely left by a group of sea turtles skimming the seafloor with their front flippers some 80 million years ago. They propose that seismic activity, possibly an earthquake, triggered a submarine avalanche, which sent the panicked turtles paddling away.

The quake "scared the bejesus out of these poor animals who were peacefully hanging around the nutrient-rich shallow water environment," Montanari says, per New Scientist.
"They all swim in panic towards the open sea on the west of the reef, and some of them reached the oozy seafloor, leaving their paddle prints." That same avalanche then covered the tracks in sediment, preserving them for millions of years, researchers say. The study team acknowledges their theory is difficult to prove and would like ichnologists, scientists who study fossil traces of tracks and burrows, to help confirm the finding.

However, not everyone is convinced. Some ichnologists say the evidence is too thin, noting the absence of certain features, like sediment piles behind the tracks, which would be expected if turtles made them. Others suggest the marks could be the result of seismic activity itself, rather than a turtle exodus. Still, the idea of a prehistoric turtle stampede has captured imaginations. As Montanari notes, whatever the cause, it appears the turtles managed to escape whatever danger they faced.