“Something crossed here from the left, very recently.”

My wife, Rachel, and I are on foot, following Tsundzukani, our tracker, in Londolozi Game Reserve in South Africa. After several days of sitting in the back of a 4x4, we are finally experiencing a walking safari. Barely ten minutes into the walk, we come across a very fresh and pronounced drag mark across our trail.

A drag mark suggests something has killed something else—and no more than 15 minutes before we passed through.

“Be still, no talking. Let us go and look and see which way this track takes us,” says Tsundzukani.