Hand stencils in El Castillo cave are older than previously thought. Image: courtesy of Pedro Saura

In a cave in northwestern Spain called El Castillo, ancient artists decorated a stretch of limestone wall with dozens of depictions of human hands. They seem to have made the images by pressing a hand to the wall and then blowing red pigment on it, creating a sort of stencil. Hand stencils are a common motif in the cave paintings of Spain and France, and like all cave art, they have long been considered to be the work of anatomically modern humans like us. But a new analysis of the age of the paintings in El Castillo and other Spanish caves shows that some of these paintings are much older than previously thought old enough, in some cases, to be the handiwork of our cousins the Neandertals .