The Laetoli Footprints: Ancient Evidence of Human Bipedalism
Over 3.6 million years ago our human ancestors went for a walk, unaware that they were making history. Their footprints were accidentally preserved in volcanic ash, surviving the time and providing modern scientists with the oldest undeniable evidence of human bipedalism.
These famous footprints, known as the Laetoli footprints, are located along the southern edge of the Serengeti plains in northern Tanzania, Africa.
First discovered by archaeologists in 1978, the Laetoli footprints were initially identified as belonging to at least 70 hominids, stretching over a 27-meter-long track. It was later revealed that these footprints likely belonged to three individuals walking together. Dating back approximately 3.6 million years, the footprints were left long before the emergence of Homo sapiens.
Most researchers agree that the footprints were left by Australopithecus afarensis, the same species as the famous skeleton known as Lucy. These hominids had a hybrid appearance between modern humans and great apes, standing around 150 centimeters tall, with a face similar to that of a chimpanzee and a stocky, hairy body. What set them apart was their ability to walk upright.
Research on the shape of the Laetoli footprints indicated that A. afarensis walked bipedally. The footprints show that the species had a big toe aligned with the rest of the foot, unlike current primates such as chimpanzees and bonobos. Researchers also deduced that they walked with a “heel strike” followed by a “toe push-off,” similar to the way we walk.
Scholars emphasize that the Laetoli footprints represent a form of human-like bipedalism, very different from that of present-day primates. These findings have upended previous hypotheses, showing that bipedalism evolved in a much older genus of hominids than previously thought.
Although A. afarensis was partially arboreal, its body retained archaic features that limited its ability to fully master bipedalism. This trait, fundamental to our evolution, contributed to our ability to walk and run long distances while carrying loads.
The future of the Laetoli site is uncertain, with researchers raising an alarm in May 2024 about the risk of losing the tracks due to erosion caused by increasingly frequent storms and rainfall, linked to climate change.
