Was the majority of prehistoric cave art in southwestern Europe done by women? That’s the theory put forth in a study conducted by archeologist Dean Snow, and it’s a welcome challenge to the long-held assumption that our ancient artist predecessors were mostly men.

Snow’s study, “Sexual Dimorphism in European Upper Paleolithic Cave Art” (© 2013 Society for American Archaeology, Dean Snow), which was published in the journal American Antiquity and sent by the author to Hyperallergic, focuses on sexual dimorphism (aka the difference in appearance between men and women), using hands as his point of comparison. This makes sense given the plethora of human handprints and stencils in cave art around the world, and Dean was inspired too by the work of a British biologist named John Manning, whose findings offered a way for determining sex in European people based on the ratio of index to ring finger lengths. In women, Manning found, the ratio is, on average, 1; in men, it’s .98.

For his experiment, Snow gathered his own samples of handprints from European-descended people and essentially confirmed Manning’s findings, devising a two-step process for determining gender based on handprint. He then took to the caves, namely a handful of Upper Paleolithic ones in France and Spain. Unfortunately, even though the caves “contain a large fraction of the 200–300 hand stencils that are referenced in a wide range of publications,” Snow writes, “only a much smaller number are complete enough or preserved well enough to be potentially measurable.” In the end, he had 32 hand stencils to work with, which he concedes “is smaller than any researcher would prefer” but insists it is nonetheless sufficient.

What Snow found among those 32 samples is that 8 appear to have been done by men, while 24 were likely done by women, making 75% of the sampled cave art the work of women. Not only is that unexpected, but it negates decades of archeological assumptions. As Snow writes: