The dulfanin reproduce like people. The Gemara asks: What are dulfanin? Rav Yehuda says: They are creatures that are called sons of the sea.

The baraita continues: In the case of any male animal whose testicles are external, the female gives birth to live offspring, and in the case of any male animal whose testicles are internal, the female lays eggs.

The Gemara asks: Is that so? But doesn’t Shmuel say that a domestic goose and a wild goose are considered diverse kinds, and one may not mate them with each other. And we discussed it: What is the reason? Abaye said: In the case of this one, the male wild goose, its testicles are external, and in the case of that one, the domestic goose, its testicles are internal. The Gemara comments: And yet both geese lay eggs. Evidently, the fact that the male’s testicles are external does not prove that the female gives birth.

Rather, the baraita must mean the following: With regard to any animal whose male reproductive organ is external, the female gives birth, and in the case of any male animal whose reproductive organ is internal, the female lays eggs. Although the testicles of the male wild goose are external, its reproductive organ is internal.

§ The baraita continues to discuss matters of animal procreation: Any species whose sexual intercourse occurs only during the daytime gives birth only during the daytime; any species whose intercourse occurs only at night gives birth only at night; any species whose intercourse occurs both during the daytime and at night gives birth both during the daytime and at night.

The Gemara elaborates: The statement that any species whose intercourse occurs during the daytime gives birth during the daytime is referring to a chicken. The statement that any species whose intercourse occurs at night gives birth at night is referring to a bat. The statement that any species whose intercourse occurs both during the daytime and at night gives birth both during the daytime and at night is referring to a human and any creature that is similar to him.

The Gemara asks: What halakhic difference is there whether an animal gives birth during the daytime or at night? The Gemara answers: The difference is with regard to that which Rav Mari, son of Rav Kahana, said. As Rav Mari, son of Rav Kahana, said: If one examined a chicken’s nest on a Festival eve and did not find an egg in it, and the following day, on the Festival, he rose early, before dawn, and found an egg in it, consumption of the egg is permitted on the Festival. It is not considered an egg that was laid on the Festival, which is forbidden (see Beitza 2a), as chickens do not lay eggs at night. Although he examined the nest before the Festival and failed to find an egg there, one is compelled to say that he did not examine the nest carefully.

The Gemara challenges: But he did examine the nest carefully, as the baraita states that he examined it. The Gemara explains: One must say that this was a case where most of the egg emerged on the eve of the Festival and returned inside its mother before the examination. And this ruling is in accordance with the opinion of Rabbi Yoḥanan, as Rabbi Yoḥanan says: In a case where most of the egg emerged on the eve of the Festival and returned inside its mother it is permitted to eat it on the Festival, as once most of it emerged it is considered to have been laid already.

§ The baraita continues: Any two animals of different species whose manner of intercourse and time of gestation are identical can have offspring together and can raise, i.e., nurse, the young of each other. With regard to the manner of intercourse, all species engage in intercourse with the face of the male opposite the back of the neck of the female, meaning that the male comes from behind the female, except for three species that engage in intercourse face-to-face, and they are these: Fish, and humans, and the snake.

The Gemara asks: And what is different about these three? When Rav Dimi came from Eretz Yisrael to Babylonia he reported that they say in the West, Eretz Yisrael, the following explanation: They are different because the Divine Presence spoke with them. This occurred when the fish swallowed the prophet Jonah (see Jonah 2:11), when Adam and other prophets were spoken to by God, and when the snake caused Adam and Eve to sin (see Genesis 3:14).

A tanna taught: A camel engages in intercourse back to back with its mate.

§ The Gemara cites a baraita that discusses the length of gestation for various animals. The Sages taught that a chicken hatches after twenty-one days, and corresponding to it in length of gestation with regard to trees is the almond, which ripens twenty-one days after the budding of the flower. A dog gives birth after fifty days, and corresponding to it with regard to trees is the fig. A cat gives birth after fifty-two days, and corresponding to it with regard to trees is the mulberry. A pig gives birth after sixty days, and corresponding to it with regard to trees is the apple. A fox and all types of creeping animals give birth after six months, and corresponding to them with regard to trees, i.e., plants, is grain.

Small kosher livestock, such as sheep or goats, give birth after five months, and corresponding to them with regard to trees is the grapevine. Large non-kosher livestock, such as camels or donkeys, give birth after twelve months, and corresponding to them with regard to trees is the date palm. Large kosher livestock, such as cows, give birth after nine months, and corresponding to them with regard to trees is the olive. The wolf, and the lion, and the bear, and the leopard, and the bardelas, and the elephant, and the monkey, and the long-tailed ape give birth after three years, and corresponding to them with regard to trees is the white fig.

The baraita continues: A viper gives birth after seventy years, and corresponding to it with regard to trees is the carob. In the case of this carob, the period from the time of its planting until the time of the ripening of its fruit is seventy years, and the length of its gestation is three years. A snake is born after seven years, and for that wicked animal we have not found a counterpart among trees. And some say that mukhsasim are the equivalent, as they ripen after seven years.

The Gemara asks: From where is this matter, that the gestation period of a snake is seven years, derived? Rav Yehuda says that Rav says, and some determined it to be in the name of Rabbi Yehoshua ben Ḥananya: It is derived from that which is stated with regard to the punishment of the snake for causing Adam and Eve to sin: “Cursed are you from among all animals, and from among all beasts of the field” (Genesis 3:14), in that your gestation period should be longer than all of them. Now, why does the verse mention the beasts of the field, i.e., undomesticated animals? If the snake was cursed more than the domesticated animals, then all the more so is it not clear that it was cursed more than the undomesticated animals? The shortest gestation period of domesticated animals, which is five months for a goat, is longer than the shortest gestation period among undomesticated animals, which is fifty-two days for a cat.

Rather, the verse mentions the beasts of the field to tell you: Just as the domesticated animals were cursed more than the undomesticated animals by a proportion of one to seven; the Gemara interjects: And with regard to what case is that? It is with regard to a donkey, whose gestation period as mentioned is twelve months, compared to a cat, whose gestation period is fifty-two days. Seven times longer than fifty-two days is 364 days, which means that the gestation period of the donkey, which is one year, is almost exactly seven times longer than that of the cat. Rav Yehuda continues: So too, the snake was cursed more than domesticated animals, i.e., the donkey, in a proportion of one to seven, which is a total of seven years.

The Gemara challenges: Say that the verse can be interpreted as follows: Just as the undomesticated animals were cursed more than the domesticated animals by a measure of one year to three years; the Gemara interjects: And in what case is that? It is in the case of a lion, whose gestation period is three years, compared to a donkey, whose gestation period is one year. The Gemara continues its challenge: So too, the snake was cursed more than the undomesticated animals, i.e., the lion, by a proportion of one year to three years, which is nine years.