Scientists have made a groundbreaking discovery in northern Kenya: 1.5-million-year-old fossilized footprints belonging to two different species of human ancestors.
These prints provide a unique snapshot of life during the Pleistocene Epoch, revealing how two distinct hominin species may have shared the same space, competing for food and surviving in a challenging environment.
The footprints were found near the shores of ancient Lake Turkana, in a savanna once teeming with wildlife.
This discovery, published in the journal Science, offers the first direct evidence that two species—Homo erectus and Paranthropus boisei—lived in the same area and used the same habitat at nearly the same time.
What are hominins?
Hominins are members of the human lineage that evolved after the split from the ancestors of great apes, around 6–7 million years ago. They include both extinct species and modern humans.
Homo erectus is a well-known ancestor of humans, known for its upright posture and use of tools. Paranthropus boisei, on the other hand, is an extinct species with a robust build and a diet focused on tough plants. While both species were bipedal and agile, they likely had different lifestyles and dietary habits.
The research team, led by scientists including Craig Feibel from Rutgers University and Kevin Hatala from Chatham University, found the footprints in 2021. The discovery was accidental. A group of highly skilled Kenyan excavators noticed fossil bones after heavy rains. While cleaning a sediment layer, they uncovered giant bird tracks—and then stumbled upon the hominin footprints.
The footprints were left in soft sediment on the ancient lake’s shoreline, and the team determined they were made within hours of each other. “This is hard evidence that two different hominin species walked the same ground at nearly the same time,” said Feibel.
Using advanced 3D imaging technology, the scientists analyzed the footprints and identified differences in foot anatomy and walking styles between the two species. This innovative method enabled them to distinguish the prints and study how these ancient humans moved across the landscape.
Unlike skeletal fossils, which can be moved by water or predators, trace fossils like footprints remain exactly where they were made. This makes them invaluable for studying behavior and environment.
“These footprints give us a vivid snapshot of how our ancient relatives lived,” said Hatala. “We can imagine them moving through their surroundings, possibly interacting with each other or other animals.”
The findings also support the hypothesis that Homo erectus and Paranthropus boisei coexisted. While Homo erectus thrived for more than a million years, Paranthropus boisei eventually went extinct after a few hundred thousand years. Scientists are still unsure why.
Footprints like these help us understand how early humans adapted to their environment. Both species walked upright and were likely skilled at navigating the savanna. However, they might have used the landscape differently based on their diets and behaviors.
The researchers believe that competition for resources, such as food and water, might have shaped how these species lived together. It’s also possible they avoided direct interaction, crossing paths only occasionally.
This discovery was made possible by a dedicated team of scientists, paleontologists, and local excavators. The fossil site was first explored by Louise Leakey, granddaughter of famed paleontologists Louis and Mary Leakey, who have made significant contributions to our understanding of human evolution.
“This discovery is a bit of serendipity,” said Feibel. “It’s rare to find such well-preserved footprints, and even rarer to have two species represented in the same place.”
This find adds an exciting piece to the puzzle of human evolution. It shows how different species of early humans lived and adapted to their environment, offering clues about cooperation and competition. It also highlights the importance of Kenya’s Lake Turkana region, a treasure trove for understanding our ancient past.
For now, these footprints provide a tangible connection to our distant ancestors, allowing us to imagine their lives and interactions as they walked the Earth over a million years ago. “This is not just a story about fossils,” said Feibel.
“It’s a story about people—real individuals who lived, moved, and thrived in a world that shaped the course of human history.”
