In a groundbreaking discovery, scientists have unearthed fossilized footprints along the ancient shores of a Kenyan lake, revealing that two distinct hominin species coexisted approximately 1.5 million years ago. These footprints belong to Homo erectus and Paranthropus boisei, providing invaluable insights into the lives of our ancient relatives and reshaping our understanding of human evolution.
The remarkable findings shed light on how these hominins navigated their existence in ancient Africa. The research team suggests that if the individuals who made these footprints did not directly overlap at the site, they would have crossed paths within mere hours of each other. This revelation challenges previous assumptions about the spatial and temporal separation between different hominin species during this time period.
Rebecca Ferrell, a program director at the National Science Foundation, expressed her excitement about this discovery, stating, “The team used cutting-edge 3D imaging technologies to create an entirely new way to look at footprints, which helps us understand human evolution and the roles of cooperation and competition in shaping our evolutionary journey.”
Homo erectus had ventured out of Africa as far as eastern Asia, while another recent study proposed that Homo floresiensis (commonly known as “hobbits”) descended from Homo erectus in Java. It is worth noting that Homo erectus survived until approximately 110,000 years ago, whereas P. boisei became extinct around 1.2 million years ago—shortly after leaving its tracks on the ancient lakeshore in Kenya.
The footprints were discovered by a team led by paleontologist Louise Leakey in 2021 and subsequently excavated during the following summer. Kevin Hatala, an evolutionary biologist at Chatham University and lead author of the paper, explained that these footprints represent the only two hominins known from the Turkana Basin during this specific time period. While it is possible that Homo habilis also lived alongside them but has yet to be discovered, for now, the evidence suggests that the footprints were made by H. erectus and P. boisei.
Homo erectus is widely considered an ancestor of Homo sapiens; however, Paranthropus presents a different narrative. This extinct human relative possessed a robust facial structure and the largest teeth among primates. Last year, researchers found three-million-year-old tools alongside Paranthropus remains, indicating that our hominin relatives may have been engaging in butchering activities long before anatomically modern humans appeared.
Both Homo erectus and P. boisei were bipedal species—walking on two legs—and demonstrated agility in their movements. They both frequented the ancient lakefront near Lake Turkana, which served as a vital resource for their survival.
Craig Feibel, an anthropologist at Rutgers University and co-author of the study, emphasized the significance of this discovery by stating, “This proves beyond any question that not only one but two different hominins were walking on the same surface, literally within hours of each other… The idea that they lived contemporaneously may not be a surprise. But this is the first time demonstrating it.”
Although it is well established that various hominin species coexisted with early Homo sapiens—including Neanderthals, Denisovans, and H. erectus itself—finding evidence of their simultaneous presence in the same environment remains rare. However, interbreeding between Homo sapiens and these other hominins has been confirmed through genetic analysis.
This recent discovery builds upon prior instances where evidence of Homo erectus and P. boisei coexistence has been uncovered. In 2020, a skull cap belonging to a H. erectus child was found alongside cranial remains of P. boisei at South Africa’s Drimolen site, part of the Cradle of Humankind complex.
William Harcourt-Smith, a paleoanthropologist at the American Museum of Natural History, highlighted the behavioral implications of this coexistence in an accompanying Perspectives article. He noted that based on the proximity of the different footprints, it is likely that H. erectus and P. boisei lived in close geographic proximity and had minimal competition between them due to their distinct diets and life histories.
Further fossil evidence holds the potential to unravel more mysteries surrounding the interactions between ancient hominin species that shared not only a timeline but also a geographical space. Many questions remain regarding how these hominins utilized their environment and interacted with one another. Nevertheless, this recently studied fossil site serves as an extraordinary window into our family tree’s history.
