Bechorot 8 - The Gestation of a Snake
All creatures copulate face to back, except for fish, man, and snakes. Why are these different? - Because they were addressed by the Divine Presence: some people were prophets, fish - in the incident with Jonah, and snake - in Paradise.
The snake was cursed more than all the beasts, and its pregnancy lasts seven times longer than that of a donkey, that is, seven years. Caesar said to Rabbi Yehoshua ben Chananya, "How long is the gestation of a snake?" Rabbi Yehoshua answered, "Seven years." Caesar then said, "But the philosophers of Athens mated the snakes, and they bore young only after three years!" Rabbi Yehoshua answered, "Those snakes had already been pregnant four years before the Athenians began to study them." Caesar was not satisfied, "But these snakes copulated when mated by the Athenians, so they could not be pregnant!" Rabbi Yehoshua answered, "The snakes copulate even during pregnancy, as do people." The Caesar said, "But the Athenians are wise, and can be trusted in their scientific findings!" Rabbi Yehoshua answered, "We the Jewish Sages are wiser than they."
Caesar then asked Rabbi Yehoshua to go, best the Athenians in argument, and bring them to Rome. Rabbi Yehoshua successfully evaded all dangers, answered all twelve problems, and tricked them into boarding his ship. He also took some earth from Athens. When he came to Rome, the Caesar saw they they were meek, and said, "These are not they, for the Athenian philosophers are arrogant!" Rabbi Yehoshua tossed some earth upon them, they regained their self-assurance and grew haughty toward the emperor.
Art: Jan van Kessel - The Enemies of Snakes