They’re evocative images of animals which were painted on to the walls of deep caves thousands of years ago by prehistoric men and women.
Now, a new study speculates that the artists who produced numerous underground works across Europe may have been hallucinating because of a lack of oxygen.
The Tel Aviv University experts, led by Yafit Kedar, speculate that the artists made a deliberate effort to starve themselves of oxygen – a state known as hypoxia – by going deep underground.
Writing in Time and Mind: The Journal of Archaeology, Consciousness and Culture, the experts said the art was a ‘conscious choice, motivated by an understanding of the transformative nature of an underground, oxygen-depleted space.’
Ms Kedar told The Times: ‘The symptoms of hypoxia are very similar to when you are taking drugs and it occurred to me that maybe we are talking about alternate states of consciousness.’
A new study speculates that the artists who produced numerous underground works across Europe may have been hallucinating because of a lack of oxygen. Among the paintings mentioned by Israeli researchers are those dating from approximately 30,000 years ago in the Chauvet cave in Vallon-Pont-d’Arc, southern France. Pictured: Reproductions of the closely-guarded works at the Chauvet cave
The researchers noted how many Palaeolithic cave paintings in Europe are hundreds of feet from entrances.
The spaces they were drawn in were accessed via narrow passages and would not have been used for daily activities.
It prompted questions as to why the early artists ventured in to such cramped conditions.
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 the effects of oxygen deprivation may have played a role in the production of the works, the Tel Aviv researchers ran computer simulations based on cave sites in France and Spain.
The paintings and engravings in Rouffignanc, in the Dordogne, which are around 2,400 feet (730 metres) from the entrance, are among those included.