Researchers found they could distinguish the gender of cave painters, and they noticed the ancient artists were mostly women.

Scientists used to believe cave paintings were created primarily by men because they depicted primarily testosterone-fueled hunting scenes, a Penn State news release reported. Smaller hand prints near the paintings had been assumed to belong to younger boys.

Dean Snow, emeritus professor of anthropology, referred back to decade old work from British biologist John Manning for the study. The researcher worked to use hand measurements to determine sex and predisposition to heart diseases.

"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."

Through this method, Snow identified a hand print in a book on Upper Paleolithic art as female. Out of five other handprints he examined, two thirds turned out to be of female origin as well.

Snow went on to look at handprints in real caves, as well as measure the hands of modern people who were of European or Mediterranean descent.

The researcher determined there were to criteria for identifying gender from one's handprint. The first was to measure the hand in five different ways, which proved to be 79 percent accurate but adolescent males were almost always mistaken to be female.

The second step was to look at the ratio of the index finger to the ring finger, and index to pinky. This measurement should allow young males to be distinguished from females. The method was about 60 percent effective for known hands, this could be because there is too much male/female overlap in modern society.

"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."

Sexual dimorphism means a differentiation between males and females.

Using the first step in the gender-determining process, Snow found only about 10 percent of handprints in Spanish and French caves were made by adult males. The second test found 15 percent were left by younger males, meaning 75 percent of the prints were from 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."

Snow also noted other populations, such as Native Americans, require a different algorithm for determining gender from a hand print.

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