Over 1.5 million years ago, two early hominin species walked within hours, or days, of each other. Ancient footprint fossils were found by palaeontologist Louise Leakey and her Kenyan research team on the edge of a lake surrounding a large dish-like, natural structure in Turkana Basin, Kenya.
Hominin describes any human species that existed before modern human beings (Homo Sapiens). Although hominins are extinct, primates such as the African Great Ape and Gorillas are closely related to ancient human species.
After dating back and investigating the structure of the newly discovered footprints, researchers were led to believe that they once belonged to a Homo erectus and a Paranthropus boisei. “If the hominins didn’t cross paths, they traversed the shore within hours of each other,” said Craig Feibel, professor in the Department of Earth and Planetary Sciences and Department of Anthropology in the Rutgers School of Arts and Sciences (RUTGERS). Using this discovery, scientists can learn more about human evolution, and how modern humans came to move on two feet.
Scientists dated back the footprints using radiocarbon dating. This method measures the carbon 12 and carbon 14 an animal has after its death. Carbon 12 is the most common form of carbon, and carbon 14 is formed when cosmic rays hit nitrogen atoms. While carbon 12 remains the same after an animal’s death, about ½ of carbon 14 atoms will decay after each half-life, which occurs every 5730 years after an animal dies. Scientists will then compare the carbon 12 and carbon 14 ratio to determine how far the animal dates back. Trace fossils, such as footprints, help scientists learn how ancient species lived, their life span, and how they interacted with others.
At this time, little is known about how these species coexisted and more research is needed to confirm the footprints belong to the Homo erectus, and the Paranthropus. Scientists are eager to take this discovery further and learn more from these footprints. They will search for evidence that shows how the two species interacted culturally, and reproductively.