Homo erectus in northern Kenya have provided experts from the Max Planck Institute for Evolutionary Anthropology in Leipzig a unique opportunity to study and understand the modern human ancestor’s movement patterns and social structure, using data that relates directly to their dynamic behaviors. Utilizing innovative analytical techniques, the team have been able to demonstrate that the H. erectus footprints have preserved evidence showing a walking style similar to that of modern humans, as well as a group structure that is also consistent with the social behaviors of humans. Habitual bipedal movement is a defining feature separating modern humans and other primates, and the evolution of this behavior within our clade would’ve had profound effects on our early ancestors’ biology. How and when a bipedal, human-like gait first emerged in hominins has long been debated, largely due to disagreements over how to infer biomechanics from skeletal remains. Additionally, certain characteristics of group structure and social behaviors which distinguish other primates and humans were believed to have emerged as a result of important evolutionary events, yet there’s no agreement on how to detect indications of group behavior through archeological or fossil records. Following the 2009 discovery of hominin footprints, found to be 1.5 million years old, near Ileret, Kenya; continued work in the region by the team from Max Planck led to the discovery of hominin trace fossils of unprecedented size for this time period, including five separate sites with a total of 97 preserved tracks that were created by a minimum of 20 Homo erectus individuals. Using an experimental method, the researchers have learned that the shapes of the footprints are indistinguishable from the shape of those of modern people who are habitually barefoot, and most likely reflect similar foot mechanics and anatomies. “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,” Kevin Hatala, with the Max Planck Institute for Evolutionary Anthropology and The George Washington University, said in materials from the Institute. Based on experimental approximations of body mass using the hominin tracks from Ileret, the team has also inferred the genders of numerous individuals who walked across these surfaces and, for the two largest excavated surfaces they have developed hypotheses in regard to the social structure of the H. erectus groups. At each of these two sites evidence exists of several adult males, which implies a certain degree of tolerance and even cooperation among them. Male cooperation underlies a variety of social behaviors which separate modern humans from other 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 behavioral dynamic in deep time,” Hatala said in the press release from the Institute. ]]>
