A Walk Through Time

Trail of hominid footprints fossilized in volcanic ash at Laetoli, Tanzania, 1978

Some 3.5 million years ago, two ancient hominids walked across an open plain in eastern Africa, perhaps traveling toward a distant lake. All record of their journey might have vanished forever--but this was no ordinary day. A nearby volcano had recently erupted, spreading ash over the landscape. Rain had fallen, giving the ash the consistency of wet cement, and the hominids' footprints were captured in fossilized tracks.

Focus On: Australopithecus

When: 4 to 2 million years ago
Where: parts of eastern, southern and central Africa
Brain Size: around 300 to 500 cubic centimeters, or roughly the same as a modern great ape
Diet: mainly plants; probably some insects and small animals
Average Adult Height:
females: 1.1 meters (3 feet, 6 inches)
males: 1.4 meters (4 feet, 6 inches)
Average Adult Weight:
females: 30 kg (66 pounds)
males: 65 kg (143 pounds)

Laetoli site in Tanzania, Africa

Interpreting the Footprints

To create the scene in the exhibit, experts interpreted footprints left behind by two ancient hominids at the Laetoli site in Tanzania. One hominid was clearly larger than the other, but their strides matched, as if the two walked side by side. If so, they were so close they almost certainly were touching.

In the hall a male and a female walk together. Was it a mother and child instead? Possibly. We'll never know for sure, but this scene is consistent with the evidence.

Laetoli homonid footprints

Who Walked Here?

The two hominids who made the Laetoli footprints were not the only ones to leave their mark in the wet volcanic ash. Scientists have also found tracks of carnivores and three-toed horselike mammals known as Hipparion.