Oh dear: Rudi has thrown another wobbly. This time his tantrum is directed at a folding canvas bush chair that he is booting across the African desert. "Why can’t one goddamn bastard of a thing ever work as simply as it could?" he howls to no one in particular. The rest of us scrape stew from our bowls and watch the Southern Cross hover in the starry chaos. We have walked 125 miles across Namibia in the past ten days. We’re used to this. We make sure Rudi is nowhere near his shotgun. Someone pries open a tin of guava halves and we eat dessert.

It was meant to be a simple walk. Rudi Loutit, an African of French and Scottish parentage, worked this desert as a park ranger and wildlife researcher for three decades—a tenure that began 15 years before Namibia’s independence in 1990. Along with his late wife, Blythe, he founded Save the Rhino Trust (SRT), and their work has helped stall the black rhinoceros’s free fall toward extinction, a fate that 20 years ago seemed all but certain. Now at age 64, with the rhino population stabilizing and the Namibian government on the verge of declaring a vast chunk of habitat a permanently protected park, Rudi—a sort of Ed Abbey, Jane Goodall, and Crocodile Dundee combo—got the idea to go for a hike.