A remarkable set of fossil footprints discovered in Kenya is giving scientists a rare look at how one of humanity’s ancient relatives lived more than 1.4 million years ago.
Unlike fossil bones, which reveal what an individual looked like, footprints capture a brief moment in time.
They show where ancient people walked, how they moved, who they traveled with, and even provide clues about their social lives.
The research, published in the Proceedings of the National Academy of Sciences (PNAS), was led by an international team of scientists from the United States and Kenya.
They studied 21 fossil footprints left by eight individuals of Paranthropus boisei, an extinct human relative that lived alongside early members of the human family during the Early Pleistocene.
The footprints were found near the shores of Lake Turkana in northern Kenya, one of the world’s most important locations for studying human evolution. This region has produced countless fossils and ancient footprints that help scientists understand how early human relatives lived millions of years ago.
The story of this discovery began almost 50 years ago. In 1978, Smithsonian researcher Kay Behrensmeyer was working in the area when she noticed a large fossilized hippopotamus footprint in the rock. As researchers carefully uncovered the ancient surface, they discovered two hominin footprints nearby. After the initial study, the site was covered again with sand to protect it from damage until better technology became available.
Scientists returned to the site in 2016 and again in 2023. They uncovered many more footprints preserved in the same layer of ancient mud. In total, they found 21 footprints from eight individuals, along with tracks left by hippos, antelope, and several other animals that once lived along the lake.
Using layers of volcanic ash preserved in the surrounding rocks, the researchers determined that the footprints were made about 1.43 million years ago. At that time, Lake Turkana was home to many large animals, including elephants, crocodiles, and hippopotamuses. Two different species of ancient human relatives also lived there: Paranthropus boisei and Homo erectus, a species considered a possible direct ancestor of modern humans.
The footprints revealed an unexpected surprise. Scientists identified them as belonging to Paranthropus boisei, but their size suggested these individuals were much larger than researchers had previously believed. Earlier studies often assumed that Homo erectus was noticeably taller and heavier than Paranthropus. Instead, these newly discovered footprints indicate that some Paranthropus individuals may have stood as tall as 6 feet (1.8 meters) and weighed around 165 pounds (75 kilograms), making them similar in size to Homo erectus.
The footprints also offered clues about social behavior. Most of the tracks appear to have been made by adult males walking together. There were no obvious footprints from females or young individuals. This suggests that groups of adult male Paranthropus sometimes traveled together, something scientists had not been able to confirm before.
Researchers believe this behavior may point to a more complex social structure than previously thought. The males may have belonged to larger communities where they competed for mates but still cooperated when traveling through landscapes filled with dangerous animals. Living and moving in groups could have offered protection from predators and other threats around the lakeshore.
Footprints provide a unique type of evidence because they record a single moment that happened long ago. Unlike bones, which may have been moved or buried over time, footprints preserve the actions of living individuals as they walked across soft mud. They allow scientists to study movement, body size, speed, and group behavior in ways that skeletons alone cannot reveal.
This site is only one of hundreds of fossil footprint locations discovered around Lake Turkana. Together, these ancient tracks are creating an increasingly detailed picture of life during a critical period of human evolution.
The research team plans to return to Kenya to continue exploring the area, hoping to uncover even more evidence of how our distant relatives lived, moved, and interacted over a million years ago. Each new discovery brings scientists one step closer to understanding the everyday lives of the ancient species that shared our evolutionary history.
Source: Smithsonian.
