“Love in the Sahel” (Part 5 of six) follows life on the move for Errou, a 16-year-old Fulani cattle herder who must leave his Niger-delta village in Mali for an eight-month grazing odyssey “on the shore of the desert,” as narrator Joe Morton calls the area just south of the Sahara. That's eight months away from his girlfriend. Water in the Sahel is scarce, so cattle and farmers must share it with elephants. They do so uneasily, but other farmers coexist happily with crocodiles.