Erik Trinkaus, a professor of physical anthropology, argues early humans living in far northern climates began placing insulation on their feet around 500,000 years ago. But frequency of use and the actual mechanical protection provided by the footwear was unclear.
Lacking physical evidence, Trinkaus analyzed the foot bones of western Eurasian Middle Paleolithic and middle Upper Paleolithic humans.
"I discovered the bones of the little toes of humans from that time frame were much less strongly built than those of their ancestors, while their leg bones remained large and strong," Trinkaus said. "The most logical cause would be the introduction of supportive footwear."
During barefoot walking, the smaller toes flex for traction, keeping the toe bones strong, he explained. Supportive footwear lessens the roll of the little toes, thus weakening them.
His research appeared in the July issue of the Journal of Archaeological Science.