Our Journey to Walk on Two Feet wasn't Linear

Fossils Show Different Humans Evolved Different Methods of Walking

Hiya!

Walking on two legs changed everything for our species. Some may argue that it was the first step (ha!) leading to the evolution of our other uniquely Human traits. Many of us learned this transformation was relatively linear, as portrayed in the image known as the March of Progress.

However, discoveries over the last few decades suggest our evolution from commuting on all fours to walking upright on two legs was less linear than previously thought. In fact, like our sinuses, our feet and walking style also seem to differ among various Human species.

The March of Progress

You’ve likely seen the March of Progress (shown below), even if you don’t know its name. It’s an iconic art piece from the 1960s that took on a life of its own. In the decades since its reveal, countless adaptations of the original have decorated t-shirts, bumper stickers, and coffee mugs.

Photo by Eugene Zhyvchik on Unsplash

The straightforward progression is a convenient assumption to believe about Human evolution. After all, walking on two legs is clearly an advantage, and we humans are obsessed with progress, so there is no reason we’d revert back to walking on all fours. I’m being sarcastic, but there is some truth to it. We prefer when things are neat and tidy, with a beginning, middle, and end. But Nature isn’t interested in straight lines or easy answers.

Nature is more like an elegant mad scientist. She creates something, then endlessly tweaks it to make it better, stronger, faster, and wiser. Nature is all about trial and error, and diversity is her most valuable tool. Diversity is everywhere we look in nature, and paleoanthropologists’ discoveries over the last two decades show that our evolution to bipedalism is no exception.

Challenging Previous Conceptions

Thanks to fossil discoveries and very savvy scientists, we now know that various Human species throughout Africa evolved different ways of walking on two legs. Once bipedalism emerged, Nature began a long journey of evolutionary trial and error, testing out various designs of walking that were anything but linear. Eventually, though, our version came about and is what eventually prevailed.

In 1976, archaeologist Mary Leakey discovered animal footprints and impressions of raindrops in Laetoli, Tanzania, from 3.6 million years ago. After further excavating what became known as Site A, Leakey and her team uncovered thousands of footprints from animals of all sizes, ranging from beetles to giraffes. After months of delicate work, members of Leakey’s team found a series of bipedal tracks.