Majority of Handprints Found in Ancient Cave Paintings from Women [VIDEO]

The majority of ancient handprints found on rocks and cave walls belong to women, research shows.

For years, researchers assumed the handprints were men's given the depictions of hunting scenes. The smaller prints, they assumed, were simply younger boy's.

Penn State anthropologist Dean Snow first got the idea for the study when studying the work of a British biologist John Manning, who attempted to use hand measurements to determine sex, among other things, including sexual preference and susceptibility to heart disease.

"Manning probably went way beyond what the data could infer, but the basic observation that men and women have differing finger ratios was interesting," Snow said. "I thought here was a neat little one off science problem that can be solved by applications of archaeological science."

Snow developed a two-step process for determining someone's sex based on his or her handprint. The first part included measuring the overall size of the hand using five separate measurements to separate the adult male hands from the rest.

Though 79 percent successful in determining sex, this method meant many adolescent males were classified as female. To solve this, the second step compared the ratios of the index finger to the ring finger and the index to the pinky, though the success rate was just 60 percent. Though statistically significant, Snow concluded that too much overlap exists between males and females in modern populations.

However, Snow determined that this was not the case anciently. Not only were men's hands larger back then, but the length of the fingers relative to one another differed significantly.

"I thought the fact that we had so much overlap in the modern world would make it impossible to determine the sex of the ancient handprints," Snow said. "But, old hands all fall at or beyond the extremes of the modern populations. Sexual dimorphism was greater then than it is now."

Using the first step in the process, the researcher determined that only 10 percent of handprints in Spain and France belonged to adult males. The second step revealed that 15 percent were left by adolescent males. Together this left 75 percent of handprints as belonging to females.

"By just eyeballing, I'm more accurate with the modern hands than the formulas I developed," Snow said. "There are some variables there that I'm not aware of yet. The algorithms are pretty good, but they could be better."

Interestingly, the rules and algorithms failed when examining modern Native American's hands, Snow found, suggesting that different populations require a different set of rules.