In a new discovery near Kenya’s Lake Turkana, scientists have uncovered fossilized footprints from two distinct hominin species dating back 1.5 million years.
This marks the first known instance of two hominin species leaving tracks on the same surface, offering unprecedented insights into how these early humans interacted with their environment and potentially with one another.
The study identifies the footprints as belonging to Homo erectus and Paranthropus boisei, two of the most prevalent hominin species of the Pleistocene Epoch.
Researchers believe the footprints were made within hours of each other on the shores of an ancient lake, showcasing the shared habitat of these early humans.
“Their presence on the same surface, made closely together in time, places the two species at the lake margin, using the same habitat,” said Craig Feibel, an author of the study.
A glimpse into hominin evolution
The term “hominin” refers to all species within the human lineage, including extinct ancestors and modern humans, dating back to the split from great ape ancestors around 6–7 million years ago. While skeletal remains have traditionally been the primary evidence in human evolutionary studies, fossilized footprints offer unique insights into behavior, anatomy, and interactions.
“Fossil footprints are exciting because they provide vivid snapshots that bring our fossil relatives to life,” said Kevin Hatala, the study’s lead author. Unlike bones or tools, footprints capture dynamic moments, revealing how ancient humans walked, hunted, and possibly interacted.
Hatala and his team used advanced 3D imaging to analyze the footprints, uncovering differences in anatomy and locomotion between the two species. This cutting-edge technology enabled the team to distinguish the tracks, contributing to a more nuanced understanding of early hominin behaviors.
Craig Feibel, a co-author and professor at Rutgers University, emphasized the significance of the findings. “Their presence on the same surface, made closely together in time, places the two species at the lake margin, using the same habitat,” he said.
Feibel, an expert in stratigraphy, confirmed the footprints’ geological age and pinpointed their formation to a narrow time window on soft sediment near the lake. The footprints, preserved as trace fossils, provide unmovable evidence of the species’ presence, unlike bones or tools that can be displaced by water or predators.
The footprints were uncovered in 2021 by a team led by Cyprian Nyete, which included local Kenyan researchers skilled in fossil excavation. During the dig, giant bird tracks initially caught the team’s attention, leading to the discovery of the first hominin footprint. Louise Leakey, a third-generation paleontologist, later coordinated the excavation, which revealed an extensive footprint surface.
Two species, one landscape
The coexistence of Homo erectus and Paranthropus boisei raises intriguing questions about their interactions. Both species were bipedal and agile, but they likely had distinct survival strategies. Homo erectus, a direct ancestor of modern humans, persisted for another million years, while Paranthropus boisei went extinct within a few hundred thousand years.
Their presence on the same surface could have placed them in direct competition for resources in a challenging environment. However, the nature of their interactions—whether cultural, competitive, or reproductive—remains unknown.
This discovery contributes to a growing body of evidence about human evolution and the dynamics of early ecosystems. Fossilized footprints, as trace fossils, offer unique behavioral insights that skeletal remains cannot.
“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,” Feibel concluded.
“The idea that they lived contemporaneously may not be a surprise. But this is the first time demonstrating it. I think that’s really huge.”
The study has been published in Nature.
