Stepping back 3.6m years: footprints yield new clues to humans’ ancestors

Tracks found by accident on proposed museum site in Tanzania were preserved in volcanic ash dampened by ancient African rains

The footprints of five ancestors of humans who walked the Earth more than 3.6m years ago have been found preserved in volcanic ash that was dampened by ancient African rains. Researchers unearthed the tracks by accident when they began to excavate test pits that had been called for as part of an assessment of the impact of building a proposed museum on the site in Tanzania.

The markings reveal that the ancient human relatives walked side by side for at least 30 metres. The footprints were laid down in a layer of ash that was subsequently buried, but which when moistened retained the tracks like clay.