Each afternoon, as the sun begins to lower over the tropical rainforests of Central and South America, the male greater sac-winged bat wakes up and gets to work. Clinging upside-down to the side of a cave or a tree cavity, he folds his three-inch body in half like a hairpin, sucking up a few drops of urine before quickly transferring it into the eponymous pouches on his wings. Then, he bends forward again, this time pressing a gland on his chest against his penis, creating a cocktail of secretions he…
