Around 1.5 million years ago, four walkers traversed the muddy shore of a lake, leaving footprints. If they did not cross paths, they would have missed each other narrowly — probably by hours if ...

like beach sand, that left a layer on the landscape. Then a light rain fell onto the ash to create something like wet cement -- an ideal material for trapping footprints. Birds and mammals left a ...

For the photo, scientists filled the hominin tracks and a few other footprints with dark sand so they would stand out against the light-colored sediment. Anna K. Behrensmeyer I could hardly ...

STEVE:'Most footprints get washed away, but we were lucky. Our ancient river flooded and filled the footprint with mud and sand, protecting it. So we've got our protective layer of sand.