Some 800,000 years ago, one of modern man’s prehistoric ancestors walked along the shore of a large lake in what is now Eritrea, in northeastern Africa. This individual’s footprints, preserved in the sandy soil, were eventually buried under thousands of years’ worth of sediment, as the lake dried up and the region transformed into arid desert. According to a team of Italian and Eritrean researchers, this is the story behind their recent discovery of what may be the oldest-ever fossilized footprints of Homo erectus.

The early hominid species Homo erectus, or “upright man,” is thought to have emerged in eastern Africa around 1.9 million years ago. They had smaller brains and larger teeth than modern humans, walked upright (as the name would suggest) and appear to have been the first human species to learn how to control fire, around 1 million years ago. Fossils of H. erectus found as far afield as South Africa, Europe, the Middle East, China and Indonesia show that the species ranged over a large portion of the globe before eventually making way for other groups, including modern humans (Homo sapiens), around 200,000 years ago.

Homo Erectus footprints. (Sapienza University)
Homo Erectus footprints. (Sapienza University)

Now, a team of researchers has discovered what may be the oldest-ever fossilized Homo erectus footprints in Danakil Desert, located in the northeastern African country of Eritrea. Italian archaeologists joined forces with researchers from the National Museum of Eritrea to uncover a slab of stone measuring some 26 meters (85 feet) square buried in a stretch of desert sand. The slab contained a set of footprints, which the researchers believe were left by a Homo erectus individual some 800,000 years ago.

“Fossilized footprints are extremely rare,” Alfredo Coppa, the archaeologist from Rome’s Sapienza University who led the dig, told the Local. In the same area, however, archaeologists have found the fossilized remains of five or six different Homo erectus individuals, and the team plans to carry out more digs nearby.

A model of Peking man (Homo erectus pekinensis), who lived from 1-2 million years ago. (Credit: TOM MCHUGH/Getty Images)
A model of Peking man (Homo erectus pekinensis), who lived from 1-2 million years ago. (Credit: TOM MCHUGH/Getty Images)

The researchers believe the region where the footprints were found looked quite different 800,000 years ago. According to their hypothesis, the prints, which are nearly identical to modern human footprints, were left in the sandy sediment along the shore of a large lake. After they filled with water, and eventually dried out, the footprints were buried by more and more sand and preserved over many thousands of years. Alongside the prints, which move from north to south, the researchers found the tracks of a gazelle-like animal that the H. erectus individual may have been stalking.

If confirmed, the discovery of such ancient H. erectus footprints promises to help scientists understand how the posture and bipedalism of early hominids evolved. As Coppa put it: “Footprints will reveal a lot about the evolution of man, because they provide vital information about our ancestors’ gait and locomotion.”

Though the prints found in Eritrea are believed to be the oldest Homo erectus footprints discovered to date, they are far from the oldest hominid prints known to exist. In the late 1970s, a team of archaeologists led by Mary Leakey found a trail of footprints measuring some 27 meters (88 feet) long, preserved in layers of wet volcanic ash in Laetoli, Tanzania. The 70 footprints in the trail were identified as 3.8-million-year-old tracks made by Australopithecus afarensis, the first of man’s ancestors to walk upright. Leakey’s team discovered the so-called “Laetoli Footprints” just a few years after archaeologists stumbled on the most famous A. afarensis specimen, the 3.2-million-year-old female skeleton nicknamed “Lucy,” while fossil-hunting in Ethiopia’s Afar Triangle in 1974.