According to a recent study, prehistoric humans in Brazil left their mark on history, literally, by carving drawings next to dinosaur footprints millions of years later.

The discovery was made at the Serrote do Letreiro site in Paraíba, Brazil. Researchers first noticed etchings, called petroglyphs by archaeologists, in 1975. However, a recent drone-aided survey revealed previously unseen carvings, leading to a new interpretation of their significance. These carvings are positioned close to dinosaur footprints dating back to the Cretaceous Period, which ended a staggering 66 million years ago.

“The fact that these petroglyphs are located right next to the dinosaur footprints is fascinating,” says researcher Leonardo Troiano. “It suggests that the prehistoric people who created them found the prints noteworthy or meaningful enough to leave their own markings nearby.”

The exact meaning of the symbols remains unclear. “They appear abstract,” explains Troiano, “and their purpose, if any, is beyond our current understanding.”

The dinosaur tracks at Serrote do Letreiro belong to three distinct types of dinosaurs: theropods, sauropods, and ornithopods. Researchers theorize that the prehistoric artists might have mistaken some of the prints for those of rheas, large flightless birds native to South America, whose tracks resemble theropod dinosaur footprints.

This intriguing find adds to the growing body of evidence suggesting that early humans might have had a deeper connection with their prehistoric surroundings than previously believed.