Much of the land consists of jungle, swamp, desert, or steep-sided plateau, none of which lend themselves to the growing of wheat or rice, or sustaining herds of sheep. Africa’s rhinos, gazelles, and giraffes stubbornly refused to be beasts of burden—or as Jared Diamond puts it in a memorable passage, “History might have turned out differently if African armies, fed by barnyard-giraffe meat and backed by waves of cavalry mounted on huge rhinos, had swept into Europe to overrun its mutton-fed soldiers mounted on puny horses.”
