There’s a lot still to be uncovered about Homo erectus, most pressingly whether or not the human-like-beings are in fact our own direct ancestors. But a new study of a series of 1.5 million-year-old footprints in Kenya provide a little more insight into the hominin clade; specifically that they walked very much like modern-day humans and maintained social group structures that we would not find unfamiliar today.
The footprints in question were discovered in 2009 near the town of Ileret, Kenya, and comprise of five different sites containing 97 tracks, which are believed to have been created by 20 separate H. erectus individuals. In other words, there’s a lot of footprints to work with.
And that’s a particularly good thing; one of the problems that scientists have faced in determining how and when hominins developed a bipedal gate (ie., became less able to swing from trees and more able to walk like we do now) has been that no one can quite decide how to infer biomechanics from skeletal remains. But researchers from the Max Planck Institute for Evolutionary Anthropology, working with international collaborators, believe that the ancient footprints provide evidence that previous fossil discoveries cannot.
The researchers used admittedly experimental approaches to determine that the Ileret footprints are “indistinguishable” from modern, habitually barefoot people. And this suggests that the H. erectus had similar foot anatomies and foot mechanics to us.
Kevin Hatala, of the Max Planck Institute for Evolutionary Anthropology and The George Washington University explained in a statement:
Our analyses of these footprints provide some of the only direct evidence to support the common assumption that at least one of our fossil relatives at 1.5 million years ago walked in much the same way as we do today.
The evidence the footprints provide doesn’t just stop there, however. By studying the footprints the team was able to determine the mass of the hominins who created them, and through that were able to determine their gender, which gives an indication of their social structures.
And what it shows is that there was likely cooperation between several adult males in the area–a key factor that distinguishes us from primates.
It isn’t shocking that we find evidence of mutual tolerance and perhaps cooperation between males in a hominin that lived 1.5 million years ago, especially Homo erectus, but this is our first chance to see what appears to be a direct glimpse of this behavioural dynamic in deep time.
So there we have it; we still don’t know if H. erectus were our direct ancestors, but we do know they were a little more like us than we might have thought.
Images CC by-SA 3.0 Gerbil on Wikimedia Commons, and by John Gurche; photographed by Tim Evanson on Flickr.