Friday, July 30, 2010

Footprint Fossils Analyzed for Ancient Human Gait

Out in the Kenyan desert, a trail of extremely old footprints are etched into sedimentary rock -- a memory of early humans and how they moved.

Created around 1.5 million years ago, these are the oldest footprints that look like those made by modern humans. A team of scientists, including Brian Richmond from George Washington University, discovered these precious fossilized prints in dried mud in 2009.

Now Richmond is working on comparing the gait and foot structure of modern humans to the collection of ancient footprints.

As Richmond told NPR in an interview about his work, these footprints provide rare insight into understanding the evolution of human locomotion.

These adaptations -- long legs and arches in our feet -- represent major differences between us and our distant primate relatives including gorillas, chimps and bonobos.

The development of specialized foot tendons, called spring tendons, paved the way for our wonderful arches. Spring tendons enhance the foot’s efficiency: some of the energy spent to drop one’s weight down when taking a step is actually stored and then returned to the leg as it rebounds.

Scientists believe that the ancient footprints were laid down by Homo erectus, a human ancestor that appeared around 1.8 million years ago. Unlike earlier ancestors, these hunted, made tools and even used fire. Homo erectus was also physically similar to modern humans with large brains and bodies.

By the looks of it, the fossilized foot impressions seem identical to the ones we make when walking across the sand. But how similar are they really? That is what Richmond and his science team want to find out.

Currently, the researches are documenting how people walk by placing reflective markers along the legs of their participants and then filming the volunteers walk in an indoor sandbox. The cameras focus on the reflectors, allowing the scientists to create computer animations of the walkers.

The next step (pardon the pun) is to analyze all the footprints with 3-D scans.

After repeating this process hundreds of times, the researchers will be able to conclusively say whether or not the prints are identical and thus shed light on just how recent our mechanisms for walking and running really are.

Hirji, Zahra. 2010. "Footprint Fossils Analyzed for Ancient Human Gait". Discovery News. Posted: July 22, 2010. Available online:

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