Published in Quaternary Science Reviews, an Italian-led study of five ancient grindstones from around 39,000 to 43,000 years ago shows that milling for food dates back to the transitional period between Neanderthals and Homo sapiens.

"This pushes back by several thousand years the earliest evidence of plant processing and flour production," said study co-author Julien Riel-Salvatore, an Université de Montréal professor who chairs the anthropology department.

"One pestle from Riparo Bombrini, a site in northern Italy that I and my University of Genoa colleague Fabio Negrino have been working on for over 20 years, shows Neanderthals also engaged in this behavior, which is something completely new, to our knowledge. "So it's a pretty major discovery."

The Neanderthal-to-Homo sapiens period was characterized by the coexistence of the Late Mousterian (Neanderthal), Uluzzian and Protoaurignacian (H. sapiens) techno-complexes in the northwest and southwest of present-day Italy.

The grindstones come from two Paleolithic sites some 1,000 km apart on the Tyrrhenian Sea side of the peninsula: Riparo Bombrini, in the Balzi Rossi archaeological area of Liguria, and Grotta di Castelcivita, at the foot of the Alburni Massif, in Campania.

Starch granules with different morphologies were found on the surface of grindstones at both sites, testifying to the use of different plants, including wild cereals, by humans who inhabited the areas at that time.