The Evolution of Lucy, a Hominin, and the Other: A Snapshot of Two Populations Probing each Other in the Nearby Koobi Fora, Kenya,

Even the term “human” is arguable. Many scholars reserve it for modern humans like us, even though we have Neanderthal genes, and they shared at least 90 percent of our hominin history from its beginnings around 8 million years ago. Evolution has been gradual, and occasional rapid phases. The record of evolution in our own genus, Homo, is already full enough to show we cannot separate ourselves with hard lines.

Nonetheless, there is enough consensus to thread the story of human evolution all the way from early apes to modern humanity. The story is centered on Africa, where countries such as Ethiopia, South Africa, andKenya are proud of their heritage, giving many of their children a more detailed answer than those in the West.

Since then, the picture has changed repeatedly and dramatically, shaped by waves of new fossil discovery, technology, and scientific techniques—often accompanied by arguments about the veracity of claims made for each new piece of the puzzle.

The partial skeleton of this small-bodied, relatively small-brained female captured the public’s imagination. Lucy, the paleo- rock star, took our major fossil evidence for bipedal walking and human-like creatures after 3 million years. The race to explain how humans became what they are now was going on.

In July 2021, researchers discovered multiple sets of ancient footprints at the Koobi Fora site in the East Turkana Area of Kenya, including a continuous path of impressions left by one hominin individual and isolated prints left by at least three others. There are various impressions of sand, reed beds and fish nest on the surface, suggesting that it was a lake shore with shallow water.

A number of previous studies have suggested that different hominin species lived alongside each other. But fossils are often scattered over large areas and their estimated dates span thousands of years. Kivell says they don’t know if they are actually bumping into each other.

“This is the first snapshot we have of those two species living on the same immediate landscape, potentially interacting with one another,” says study co-author Kevin Hatala, a palaeoanthropologist at Chatham University in Pittsburgh, Pennsylvania. The study was published in a journal.

The more distant relative Paranthropus boisei was the forebear of Homo erectus, the forebear of modern humans. The two individuals walked through the lake area within hours or days of each other — leaving the first direct record of different archaic hominin species coexisting in the same place.

Researchers used 3D X-ray-based techniques to study how a foot moves. They compared arch depth and toe angles in the hominin footprints with those of humans. The isolated footprints are thought to be those of individuals of H. erectus, thought to be the first humans to walk and run upright.

The site contained tracks from relatives of cattle, three horselike animals and 61 birds, including a giant extinct stork.

Hatala hopes to combine fossil footprints and bone fossils to give a high-resolution picture of what is happening during this phase of human evolution.

Wood says that future studies could focus on the animals and birds. It is very difficult to do with regular fossil evidence, but with that, it just brings the whole thing alive.