Bechoros Daf 8 בכורות דַף 8

A lengthy Baraisa discusses the breeding of various creatures. Nonkosher fish spawn live young, whereas kosher fish lay eggs. All creatures which bear live young nurse them, while those which lay eggs gather food for them. כל שתשמישו ביום יולד ביום – all [creatures] which mate during the day, such as chickens, give birth by day; those which mate at night (such as bats) give birth at night, and all those which mate both by day and night (such as people) give birth either by day or night. Based on this principle, if one inspected a chicken’s nest on Erev Yom Tov and found no eggs in it, and arose before dawn and found an egg there, the egg is permitted (i.e., not מוקצה), because it was definitely laid during the day, before Yom Tov. Although he had inspected the nest, the majority of the egg must have emerged the previous day (and then retracted), making it permitted for use on Yom Tov. Creatures whose manner of mating and lengths of gestation match are able to crossbreed and raise each other’s young.

A Baraisa discusses the gestation period of numerous animals, and their counterparts among trees. For example, a cat is born after fifty-two days, and its counterpart is the mulberry. The Baraisa continues until concluding that a snake is born after seven years, ולאותו רשע לא מצינו חבר – and for that wicked one we find no counterpart (some say the מוכססים is its counterpart). This is derived from when the נחש was cursed: ארור אתה מכל הבהמה ומכל חית השדה – you are accursed beyond all the beasts of the field and beyond all the animals of the field. Just as the בהמה was cursed seven times more than the חיה – a donkey’s twelve-month gestation is seven times a cat’s fifty-two days – so too, the snake is cursed seven times more than the חמור (i.e., a seven-year gestation).

When Rebbe Yehoshusa ben Chananyah told the Caesar that a snake’s gestation is seven years, the Caesar responded that סבי דבי אתונא – the sages of Athens had mated snakes which bore young after only three years. Rebbe Yehoshua replied that those snakes had already been pregnant for four years beforehand. The Caesar protested that the sages of Athens are wise (and would have conducted their experiment properly), but Rebbe Yehoshua replied: אנן חכימינן מינייהו – we are wiser than they.

The Caesar told Rebbe Yehoshua ben Chananyah that if he was wiser than the סבי דאתונא, זיל זכינהו ואיתינהו לי – then defeat them in a debate and bring them to me. Rebbe Yehoshua had a ship built with sixty compartments. The Gemara relates how he found the entrance to the sages’ locale and contrived to have the inner and outer guards killed. He found the younger sages above, and the older sages below; realizing he would be killed for greeting either group first, he said only, "שלום לכו" – Peace unto you! He engaged the סבי דאתונא in a battle of wits, stipulating that they could do whatever they pleased to him if he lost, while if he won, they would dine with him on his ship. The Gemara relates their battle of wits, which included numerous absurd questions. For example, they challenged him to say a completely empty (untrue) statement. He replied that a female mule had given birth, and the offspring was born carrying a note stating that  the father mule of a hundred thousand zuz. He eventually brought them onto his ship, taking along soil from Athens, and brought them to the Caesar. The Gemara then relates their ultimate demise.