Mysterious marks on Ice Age cave art may have been ancient records

Ice Age hunter-gatherers may have been writing down markings to convey information about their prey’s behavior as early as around 25,000 years, according to a new study.

These markings include dots, lines, and the “Y” symbol, and often accompany images of animals. Over the past 150 years, the mysterious depictions, some dating back nearly 40,000 years, have been found in hundreds of caves across Europe.

Some archaeologists have speculated that the markings may relate to tracking of time, but the specific purpose has remained elusive (SN: 7/9/19). Now, a statistical analysis published January 5 in the Cambridge Archaeological Journal provides evidence that ancient humans may have recorded the mating and birthing schedule of local fauna.

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By comparing the markings to the animals’ life cycles, the researchers showed that the number of dots or lines in a given image correlated strongly with the month of mating for all the samples analyzed, including aurochs (an extinct species of wild cattle), bison, horses, mammoths and fish. In addition, the position of the symbol “Y” in a sequence was a reference to the month of birth, suggesting that “Y” means “to give birth”.

The find is one of the earliest records of a coherent system of notation, the researchers say. It suggests that people at the time were able to interpret the meaning of an object’s position in a sequence and use a kind of calendar to plan ahead into the distant future – reinforcing the suggestion that they were capable of complex cognition.

Based on the position of the “Y” in this line drawing reproduction, the chamois (a “goat antelope”) gave birth in the second month after the snow melted, researchers say.B. Bacon et al./Cambridge Archaeological Journal 2023

“That’s a really big thing cognitively,” says Ben Bacon, an independent researcher based in London. “We’re dealing with a system that has intense organization and intense logic.”

A furniture restorer by day, Bacon spent years trawling through scholarly articles to compile over 800 specimens of these cave markers. From his research and reading the literature, he concluded that the dots corresponded to the 13 lunar cycles in a year. But he thought the hunter-gatherers were more concerned with seasonal changes than the moon.

In the new publication, he and his colleagues argue that instead of pinning a calendar to astronomical events like the equinox, hunter-gatherers started their calendar year with the spring snowmelt. Not only would snowmelt be a clear place of origin, but the meteorological calendar would account for differences in timing between locations.

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For example, although snowmelt began at different times at different latitudes, bison always mate about four lunar cycles—or months—after snowmelt in that region, as indicated by four dots or lines.

“That’s why it’s such a clever system, because it’s based on the universal,” says Bacon. “That means if you migrate from the Pyrenees to Belgium, you can just use the same calendar.”

He needed data to prove his idea. After compiling the markers, he worked with academic researchers to identify the timing of migration, mating, and birth for common Ice Age animals targeted by hunter-gatherers, using archaeological data or with similar modern animals compared. Next, the researchers determined whether the markings based on this calendar significantly coincided with important life events. When the team performed the statistical analysis, the results strongly supported Bacon’s theory.

In explaining the marks, “We’ve argued for notation systems before, but it’s always been quite speculative as to what people counted and why they counted,” says Brian Hayden, an archaeologist at Simon Fraser University in Burnaby, British Columbia, who wrote the paper appraised. “This adds a lot more depth and specificity to why people keep calendars and how they use them.”

Language experts argue that given the lack of conventional syntax and grammar, the characters would not be considered written. But that doesn’t make the find any less exciting in itself, says paleoanthropologist Genevieve von Petzinger of the Polytechnic Institute of Tomar in Portugal, who was not involved with the study. Writing systems are often mistakenly seen as the pinnacle of achievement, when in fact writing would only be developed in cultural contexts where it is useful, she says. Instead, it is important that the markers provide a way to keep records outside of the mind.

“In a way, that was the big cognitive leap,” she says. “Suddenly we have the ability to preserve [information] beyond the moment. We have the ability to transmit it across space and time. Everything starts to change.”

The debate about the meaning of these signs continues. Archaeologist April Nowell doesn’t believe many of the team’s assumptions. “I don’t understand why you need a calendar … to predict that animals will have offspring in the spring,” says Nowell of the University of Victoria in British Columbia. “The amount of information that this calendar provides, if it really is a calendar, is pretty small.”

Hayden adds that while the basic pattern would still stand, some of the cave markings had “room for interpretation”. The next step, he says, will be to review and verify the interpretations of the markers.