Climbed a tree lately? If so, you may be one of 7.7 (or more) percent of humans who have flexible feet like chimpanzees — especially suited for climbing trees.

New research shows that not everyone has rigid feet. In one new study, 400 adults walked barefoot around the Boston Museum of Science while researchers filmed their steps. The recording reveals that about 1 in 13 of the participants have feet that bend both at the ball of the foot and halfway between the heel and the ball. In most humans, ligaments span that joint between the heel and the ball and hold it rigid, according to New Scientist.

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The more rigid foot may be an adaptation since we started walking more, Boston University researcher Jeremy DeSilva suggests. ”My guess is that we are getting more variation than ever before, perhaps because shoes have impacted foot anatomy,” he told New Scientist.

Researchers aren’t yet sure of all of the implications of flexible feet. Robin Huw Crompton at the University of Liverpool, author of a forthcoming study that will point to an even greater percentage of flexible feet than DeSilva’s work, thinks most people’s feet may have the capacity to be flexible.

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“For instance, our work shows that it is important during a sudden change of speed,” he told New Scientist.

Regardless, that’s a good enough excuse to check out a tree fort this weekend.

Image: iStockphoto