Rocks yield ancient footprints
Stirred out of his midday snooze, the large hippopotamus emerged from the crocodile-infested waters and lumbered onto the lake shore, leaving giant footprints in the mud. Soon a small, upright figure appeared. Perhaps looking for prey, he carefully trod among the wading birds and other fauna, crossing the trail of large prints along the shore.
A poacher at work in the back country of contemporary Africa? No: this scene, or at least something like it, occurred some 1.5 million years ago, at the edge of Lake Turkana, formerly called Lake Rudolph, in northwestern Kenya.
By himself the creature would hardly...