We walk in silence for an hour, every snap or crunch of Africa’s sun-scorched bush ricocheting through the burning air like a gunshot. Sound and smell could betray us here, in this vast expanse of the Sera Conservancy in northern Kenya, and while I keep my eyes to the ground, dodging branches and side-stepping leaves, my Samburu guide Sammy is watching the wind. Shaking a sock, a wisp of ash floats south before he signals me to move on, slow, silent, single file, and then: Do. Not. Move. A thorn-laden acacia, just 20m ahead, begins to shake violently. The perpetrator is hidden, but undoubtedly huge.