Animal symbol pictures daubed on the walls of the caves were aged by chemically dating the paints and compared it to the ancient skies.
The results showed that what looked like abstract depictions of animals could be interpreted as zodiac signs based on constellations as they appeared at the time.
The team decoded the well-known Shaft Scene from Lascaux in France, dating from 17,300 years ago, which depicts a prostate man with a bird’s head, alongside a bison, with a duck and rhino nearby.
Although it was once thought to represent a hunting or shamanic scene, the researchers now believe it shows the constellations of Capricorn during the summer solstice, Libra during the spring equinox and Taurus at the autumn equinox.
A nearby picture of a horse represents Leo in the winter solstice, according to researchers.