Are there hashtags in cave art?

Not really, but the crosshatch (or pound symbol) did show up on cave walls long before people ever knew how to write. There is an eight-minute YouTube video posted in September 2016 from National Geographic by Genevieve von Petzinger titled Ice Age Cave Art: Unlocking the mysteries behind these markings. At 3:40 there is a chart showing 32 different geometric signs. There also is a 12-minute TED talk video of hers from 2015 titled Why are these 32 symbols found in caves all over Europe?

An article in the November 12th issue of New Scientist magazine by Alison George titled Hidden Symbols had more charts indicating the crosshatch symbol also showed up in East Africa, Southern Africa,  North America, Australia, and India. You can find more in Genevieve von Petzinger’s May 2016 book The First Signs: Unlocking the mysteries of the world’s oldest symbols.

We don’t really know what the crosshatch symbol means. A reasonable guess is that it represents a net or a trap, and signifies that we are hunters, trappers, or fishermen. Or, it could indicate that back in the Ice Age people amused themselves around the fire by playing Tic Tac Toe. 

Where are these markings found, and how old are they? A web page from the Bradshaw Foundation on Geometric Signs & Symbols in Rock Art says:

“Out of the 27 sites where this sign type is present, 22 of these are from the Magdalenian. With only one site each in the Aurignacian, Gravettian, and Solutrean, it is hard to know what made people choose to keep reproducing this sign in such a small percentage of the sites. The Magdalenian explodes on the scene with nearly one in three caves from this period including the crosshatch symbol. There is a clear grouping of sites along the Pyrénées using this sign, as well as a strong presence in SW France. There are also two sites in the north with crosshatch signs from this period, but none in the SE region. The Late Magdalenian displays a sharp drop in frequency, with only two sites from this period having crosshatch signs present. When I see such an abrupt change in popularity, both before and after the Magdalenian, it makes me quite curious as to whether this trend would become any clearer if there was a larger spatial dataset to work with. Moving into nearby countries such as Spain, Portugal and Italy may allow some better patterns to emerge. As well, there are quite a few examples of crosshatches on portable pieces of art, so doing a cross-comparison with this other form of Ice Age art could help to explain this distinct, but slightly mysterious pattern of use.”

The Aurignacian was  from 43,000 to 26,000 years ago, the Gravettian was 29,000 to 22,000 years ago, the Solutrean was 22,000 to 17,000 years ago and the Magdalenian was from 17,000 to 12,000 years ago.

The cave painting image (minus the hashtag) came from Wikimedia Commons.