Cave paintings date back at least 44,000 years and are among the earliest known forms of human culture and storytelling.
But how did our primitive ancestors create detailed, often colorful scenes on cavern walls in the dark, without artificial light or even matches?
Archaeologists in Spain have examined prehistoric cave art sites to determine how Paleolithic humans could see well enough to express themselves artistically in these lightless passages.
They re-created primitive torches and lamps to determine which would have most likely been used by Stone Age artists.
Archaeologists in Spain fashioned torches and lamps similar to the ones used by Stone Age cave dwellers. They found torches were good for exploring larger areas but generated a lot of smoke and needed constant maintenance
‘We are really interested in all the production processes behind these images,’ Diego Garate, a cave art specialist at Spain’s University of Cantabria, told CNN.
‘They could have made drawings just at the entrance of the cave without any problem. They wanted to do it in these narrow places and go very deep inside the caves. That was part of it.’
Using charcoal residue and other archaeological evidence at cave art sites, Garate and his team attempted to re-create the sort of lighting available to Paleolithic humans as they created (and viewed) their work.
They fashioned five torches made with dried juniper wood, like the remains of torches found in the Aldene and Reseau Clastres caves, Ars Technica reported, and used birch bark for tinder and pine resin, ivy and deer fat for fuel.
At left: A re-created sandstone lamp gives off a semicircular arc of light. The researchers found the lamps were good for illuminating a small space over a longer period
They also carved a pair of sandstone lamps, replicas of ones found in La Mouthe Cave in France’s Dordogne region, using dried juniper wood as a wick and cow marrow as fuel.
A small, stationary ‘fireplace’ was also constructed, using dried juniper, oak and green birch bark as kindling.
Archaeologists tried to create simple torches similar to authentic ones (left) found in Paleolithic cave dwellings
The archaeologists tested their three lighting techniques inside Isuntza 1 Cave, one of the better known cave-art sites in northern Spain’s Basque region.
They chose two locations in Isuntza—a large, wide chamber with bedrock walls and a smaller, second site connected by a 130-foot long-corridor.
‘We walked for 20 minutes inside the cave until the light was getting low,’ Garate, lead author of a new report in the scientific journal PLOS One, told CNN.
`It was pretty striking that the light from the torches is really different from the artificial light we are used to.’
A majority of the best known Paleolithic cave art has been found in Spain and France
Able to project light nearly 20 feet, the wooden torches were easier to transport and worked best for exploring or crossing wider spaces.
The torches were tested in both sites and their flame, which lasted between 20 minutes and an hour, was five times brighter than a grease lamp.
But they produced a large volume of smoke and were unpredictable, often needing to be waved back and forth to keep lit.
Only tested in the first, wider cavern, the lamps proved better for lighting a small space over a longer period of time—say, when an artist was working on a section of a mural. With light about as intense as a candle, they could illuminate a diameter of about 10 feet, Inside Science reported, burning consistently for more than an hour without much monitoring and little smoke.
Creating a stationary fireplace (above) proved the least effective means of illuminating deep in caves, the researchers report, because they burned quickly and generated a lot of smoke
The lamps were poor for navigating the caverns, though, because they didn’t illuminate the ground.
The stationary fires, also just tested in the first site, burned quickly and generated a lot of smoke, making them unsuitable for either exploring or painting.
Whatever light those prehistoric Picassos used may have looked pretty trippy to them: a recent study from Tel Aviv University suggests Paleolithic cave painters may have hallucinated due to a lack of oxygen.
Writing in Time and Mind: The Journal of Archaeology, Consciousness and Culture in April, archaeologist Yafit Kedar said the cave artists likely induced hypoxia, or oxygen starvation, as ‘a conscious choice, motivated by an understanding of the transformative nature of an underground, oxygen-depleted space.’
‘The symptoms of hypoxia are very similar to when you are taking drugs,’ Kedar told The Times of London. ‘It occurred to me that maybe we are talking about alternate states of consciousness.’
Recent research suggests a lack of oxygen, known as hypoxia, would have made prehistoric cave painters experience euphoria, hallucinations and out-of-body sensations such as floating or flying. Pictured: The Lascaux cave in Lascaux, France
Early man could have left his mark on walls near cave opening, but most Palaeolithic cave paintings in Europe are hundreds of feet or further from entrances, often accessible only via narrow passages not used for daily activities.
The paintings, produced across a wide area of Europe between 40,000 and 14,000 years ago, depict animals including mammoths, bison and horses.
To find out whether oxygen deprivation may have played a role in the production of the works, the researchers ran computer simulations based on cave sites in France and Spain—including the paintings and engravings in Dordogne’s Rouffignac cave, which are around 2,400 feet from the entrance, and El Castillo cave in Cantabria, northern Spain, some 660 feet from the entrance.
Using computer modeling, Kedar’s team determined oxygen in the artists’ bodies would have fallen rapidly at those depths and would have induced hypoxia.
Normal concentrations of oxygen in the atmosphere are around 20 percent, with the rest mostly made up of nitrogen.
Their computations suggested that, for a Stone Age artist using primitive tools to make a mural, oxygen levels would have fallen below 18 percent, the threshold for hypoxia, within 15 minutes.
Severe hypoxia, with oxygen falling below 11 percent, could have happened within a few hours if they were working in a cramped space where the roof was lower than three feet.
Both hypoxia and environments such as deep caves increase the release of the neurotransmitter dopamine, the researchers noted.
While potentially deadly, hypoxia can result in euphoria, hallucinations and out-of-body sensations such as floating or flying.
In such a state, the art works on the cave walls may have appeared to float, Keder theorized, suggesting the paintings were a way of communicating with gods or other worlds.
CAVE ART: WORKS DATING BACK NEARLY 45,000 YEARS HAVE BEEN DISCOVERED
The famed Upper Paleolithic cave art of Europe dates back about 21,000 years, but a subterranean work in Indonesia depicting a hunting scene is believed to be at least 44,000 years old.
The most famous cave art can be found in Spain and France, but works exist throughout the world. Pictured: Hand stencils found in the El Castillo cave in Cantabria, Spain
‘Cave art is everywhere. Every major continent inhabited by homo sapiens has cave art,’ MIT linguistics expert Shigeru Miyagawa wrote in the journal Frontiers in Psychology in 2018.
‘You find it in Europe, in the Middle East, in Asia, everywhere – just like the human language.’
In a 2015 PLOS One journal report, Garate compared the rock art found in three caves on the Aitzbitarte Hill in the Basque Country to other art from across the continent.
While the engravings matched the style of those found elsewhere in Europe, such design was previously unknown on the Iberian Peninsula.
‘The artwork in the Aitzbitarte caves consists mostly of engravings of bison, complete with the animals’ characteristic horns and humps,’ Garate wrote.
A ‘common art culture’ existed across Europe more than 25,000 years ago, analysis of engravings of bison found in caves in Spain has revealed.
The animal’s horns and legs are drawn in a very particular style, he noted — typically without proper perspective.
‘Pairs of limbs are consistently depicted as a ‘double Y’ with both legs visible — and the horns are similarly draw side-by-side with a series of lines in between,’ he added.
The researchers compared their analysis of the Aitzbitarte engravings with other cave art found across Europe — finding that it belonged to an existing art style that appears to have been more widespread and varied than previously appreciated.