New research reveals that wearing shoes alters the internal structure of ankle bones, forcing scientists to rethink how they compare modern humans to ancient ancestors.
By Adam Makins·
For decades, researchers studying human evolution have relied on a simple comparative method: examine fossil ankle bones and compare them to the ankle bones of modern humans. But there’s a hidden variable no one was properly accounting for until now. Shoes.
A groundbreaking study from the University of Chicago and UNT Health Fort Worth reveals that habitual shoe-wearing creates measurable structural changes in the trabecular bone of our ankles. This spongy, strut-like network inside bones adapts throughout our lives based on the forces our bodies experience. And it turns out, shoes fundamentally change those forces.
Researchers used high-resolution CT scans to create 3D maps of ankle bones in 56 modern humans. The comparison groups were revealing: shoe-wearers from the US who died since 2000 versus a barefoot group consisting of 13 Andaman Islanders, two Khoisan people from southern Africa, and one Aka hunter-gatherer from Central Africa, all from the 19th century.
The results were striking. Barefoot populations showed dense trabecular bone toward the front of the ankle, consistent with a flexed foot position used in squatting and climbing. Their bone struts ran in multiple directions, indicating their ankles experienced forces from varied angles. Shoe-wearers, by contrast, had greater overall bone volume concentrated toward the inside and back of the ankle, with struts aligned more uniformly in particular directions.
This isn’t just anatomical trivia. Shoes, especially those with heels, shift loading toward the inner ankle and hold the foot in an extended rather than flexed position. Over a lifetime, this rewires how bone deposits itself internally.
Zewdi Tsegai, one of the lead researchers, notes that studying barefoot populations offers a “window into the past” for understanding how our extinct relatives actually moved. This is crucial because fossil evidence is finite and fragile. Every detail we can extract from ancient bones helps us reconstruct the truth about human locomotion.
Hanna Farrell at UNT Health Fort Worth emphasizes that different hominins used different walking styles, foot positions and amounts of climbing. Our ancestors didn’t all move the same way. By comparing fossil ankles to the ankles of shoe-wearing modern humans, scientists have inadvertently been looking through a distorted lens.
Malorie Albee at Northern Michigan University calls this “crucial baseline information” for understanding foot evolution in our science lineage. But it also raises uncomfortable questions about the assumptions embedded in comparative anatomy.
Thomas Püschel at the University of Oxford emphasizes that “something as culturally and behaviourally important as habitual footwear can be associated with measurable differences in internal bone architecture.” That’s a powerful statement. It means we need to think carefully about what our comparative samples actually represent.
This research doesn’t invalidate previous studies, but it does require more nuance going forward. Researchers must now account for compounding factors like body size, activity levels, terrain, and overall lifestyle differences. The work of teasing these variables apart will take time.
But there’s something philosophically interesting here too. We often think of evolution as this grand process operating over millions of years, shaping our bones through natural selection and adaptation. Yet a simple human invention like shoes can reshape our skeleton within a single lifetime. It reminds us that our bodies remain profoundly responsive to our choices and environments.
The researchers aren’t resting on these findings. Farrell says they’re “just trying to do the footwork to better inform more studies moving forward.” The next phase will be more rigorous, more careful, and hopefully more honest about the assumptions baked into how we compare ourselves to our ancestors.
Source: New Scientist
