The Prehistoric Paintings on the Walls of Caves Have Always Been Moving. But With the Right Kind of Light, Some Actually Seem to Move

Last year, I followed two archaeologists through a heavy metal gate into a cave called El Castillo, in northern Spain. Artists likely visited the cave many times between 13,000 and 41,000 years ago, with only torches and rudimentary lamps to help them avoid dangerous falls and cave bears with claws capable of lacerating stone. They entered the deepest, darkest chambers and made engravings and drawings of not only animals but also red disks, hand stencils and geometric patterns—nearly 3,000 of which remain legible today.

Cave bears went extinct more than 24,000 years ago, and El Castillo was outfitted with stairs and electric lighting for tourists in the 1950s. We passed through the first large chamber and turned down a passage-way normally off limits for visitors. We stopped to admire the so-called Polychrome Panel, or the Panel of Superimpositions, where many artists, over thousands of years, had crowded a wall with a mixture of hand stencils and outlines of animals in black charcoal and red, orange and brown ochres, faded to varying degrees.

I would have liked to press my own palm against a stencil and shake hands across more than 30,000 years, but of course this was forbidden. You can’t touch anything,” said the other archaeologist, Diego Garate, a professor at Spain’s University of Cantabria, “but obviously, for Paleolithic people, it was the contrary. They were in a close relationship with the walls.” (So close, in fact, that researchers from the Max Planck Institute were recently able to recover ancient human DNA from some decorated cave walls.) What motivated prehistoric people to create art in caves, often at great personal risk?

The question has preoccupied and divided archaeologists ever since the discovery of the exquisite red-and-black bison on the ceiling of the Altamira cave, in northern Spain, in 1879. When Garate began his studies more than a century later, many scholars were still trying to crack the code. Different theories had slid into and out of fashion—that the animals were totems of different clans, representations of male and female fertility, or marks made by shamans in altered states of consciousness.

Many scholars believe that the emergence of cave art was the moment when Homo sapiens became behaviorally modern, the product of a newly evolved capacity for symbolic and abstract thought. As Garate visited more caves in Spain and France, helping discover around half a dozen decorated caverns in the Basque Country, he wondered less about the artists’ intentions and more about their experiences in the sites. Nowadays no one dares to light a smoky torch or touch the walls in the delicate environment of a cave like El Castillo, so Garate was happy, around a decade ago, to find a cave near a crowded Basque beach whose only artwork was some recent graffiti.

The first time Garate lit a torch inside that cave, the flame illuminated only a dozen feet or so, and its flickering red light moved constantly and danced with shadow. It was a completely different experience from exploring a cave with the white beam of a flashlight. Other archaeologists, too, have turned their attention from drawings and etchings in isolation to other components of cave art, like lighting, placement, sound and touch.