This paper aims to highlight what is specific to Herodotus' narratology in his description of what happens to the winged snakes of Arabia (3.107-110). The ring composition allows him to build a crescendo of horror and θῶμα thanks to examples of the animal balance of species (hares, lionesses and vipers). It weaves together different authorial voices with his own voice in order to deliver a lesson about the foresight of the divine (so that humanity is not wiped out) in his own vocabulary of revenge. A close reading of a passage in Plato's Protagoras, where Protagoras describes the animal balance of species in his famous myth using the same rare vocabulary, suggests Plato is creating an intertextual play against this very passage, aiming to assert what divine foresight about mankind really is.