This story was originally published on The Conversation and appears here under a Creative Commons license. Perched about 325 feet (100 meters) up the slopes of the Prealps in southern France, a humble rock shelter looks out over the Rhône River Valley. It’s a strategic point on the landscape, as here the Rhône flows through a narrows between two mountain ranges. For millennia, inhabitants of the rock shelter would have had commanding views of herds of animals migrating between the Mediterranean region and the plains of northern Europe, today replaced…