A pair of archaeologists, one with Adam Mickiewicz University in Poznań, the other with the University of Warsaw, both in Poland, has found evidence suggesting that rock carvings found in a southern part of Peru may have been inspired by people singing while consuming hallucinogenic plants. In their study, published in the Cambridge Archaeological Journal, Andrzej Rozwadowski and Janusz Wołoszyn analyzed rock carvings found in Toro Muerto.

The researchers suggest that most of the petroglyphs appear to have been thought out or planned prior to carving—their coloring and uniform spacing suggest the artists knew what they were going to do beforehand.

They also note that most of the carvings followed similar themes—most involved danzantes surrounded by zig-zag or squiggly lines, dots or sometimes circles. They suggest the zig-zags were carved to accentuate the energy and movement associated with wild dancing.

The researchers note that the carvings are very much like those done by the Tukano, early people living in what is now Colombia. Prior research has shown that most of those carvings were made during rituals by people consuming ayahuasca, which is made using hallucinogenic vines.