A discovery in Kenya has revealed that Homo erectus and Paranthropus boisei, two distinct hominin species, coexisted 1.5 million years ago, according to reports. According to a study published in the journal Science on Thursday, the footprints were uncovered at Koobi Fora near Lake Turkana in 2021. These findings suggest that these two species not only shared the same environment but may also have interacted. The team, led by Kevin Hatala, a paleoanthropologist from Chatham University, analysed a 26-foot-long trail of fossilised footprints.

Using advanced 3D imaging techniques, researchers identified tracks belonging to individuals with distinct foot shapes and walking patterns. As per source, it was concluded that the footprints with high arches and heel-to-toe strides were left by Homo erectus, whose body structure closely resembles that of modern humans. In contrast, the flatter footprints, marked by deeper forefoot impressions, were attributed to Paranthropus boisei, known for its robust build and divergent big toe.

According to the study, the footprints offered detailed insights into the anatomical differences between the species. A single trackway contained a dozen prints from a P. boisei individual, whose foot size was equivalent to a modern US men’s size 8.5.

Meanwhile, the H. erectus footprints were smaller, correlating to shoe sizes between a women’s 4 and men’s 6. Jeremy DeSilva, a paleoanthropologist from Dartmouth College, told Live Science that this discovery provides a rare glimpse into their locomotion and potential behavioural dynamics.

Implications for Hominin Interaction

Hatala told the publication that these species likely recognised each other as distinct, drawing comparisons to the interactions observed between chimpanzees and gorillas today. Zach Throckmorton, a Colorado State University paleoanthropologist, reportedly highlighted that the stability of the big toe, evident in H. erectus, is a crucial adaptation for walking and running.

The overlapping tracks, made within hours of each other, suggest that these species shared a landscape in closer proximity than previously thought. While their precise interactions remain speculative, the discovery opens new avenues for understanding early human evolution.