Explanation: Being that the meat (i.e. limb of the baby animal) went out of its walls (i.e. the body of the mother animal) it became forbidden, as the Gemara derives later that it becomes similar to a Treifah that has no way of being permitted (in its current status). (If it is slaughtered separately from the mother it can still be permitted.)

Question: Perhaps the Mishnah wants to teach us that even though it retracted its head it is considered as if it is born? We only know from the Mishnah in Bechoros (46a) that if it does not retract its head it is considered born!

Answer: It is obvious that being that without retracting its head it is considered born, even when it retracts its head nothing has changed.

Answer (cont.): However, without the Mishnah in Bechoros (ibid.) there would not be a difficulty regarding why the Mishnah had to say it retracted its head.

Answer (cont.): Being that the Mishnah had to teach us that sticking out its head is considered birth, it also teaches us as an aside that retracting its head is insignificant. However, it is not logical to say that the Mishnah said the entire case again to teach this minor teaching.

Implied Question: One also should not ask that we need our Mishnah to teach that even what is inside is forbidden, as according to Rebbi Yehudah the prohibition refers to the (entire) fetus, and this is not understood from the text of the Mishnah in Bechoros.

Answer: This is also obvious being that it is considered born, and (accordingly) even what is inside is forbidden because the fetus is whole. When it is cut up there is a question later in the Gemara, as I will explain later with the help of Hash-m.

Question: This is difficult. The Gemara should have asked in a more simple manner that being that the Mishnah states he is not a Bechor for a Kohen, it must be that once his head is out he is considered born! (Why instead does the Gemara differentiate between the head being alive and it being dead?)

Answer: It is possible to push this aside by saying "his head" really means most of his body. This is similar to the way the Gemara in Bechoros (46b) answers a different question.

Answer (cont.): Shmuel says (ibid.) that the head does not exempt if it is a Neifel. The Gemara asks from the fact that the Mishnah says (that the following child) it is not a Bechor for a Kohen. The Gemara answers that "his head" in fact means most of his body. This means that his head came out first, and then most of his body came out.

Answer (cont.): The Gemara asks, (if this is what the Mishnah means) why doesn't it explicitly state most of its body? The Gemara answers that it says "his head" in order that we should deduce that if his head is alive, the next child is not even a Bechor for inheritance. Accordingly, the main question is from this deduction.

Observation: The Gemara also could have asked a question from the Mishnah in Nidah (28a) that says that if it went out normally, when most of its head goes out (it is considered born). What is "most of its head?" It is when the forehead comes out.

Explanation: The term "Prozdor" - "hallway" used here does not mean the same thing that it means when the Gemara in Nidah (42b) says, "Being that the baby animal stuck its head out of the Prozdor, it is considered born."

Explanation (cont.): If our Gemara would mean what the Gemara there means, how could the corridor stop the baby from being considered born once the head is outside of it?

Explanation (cont.): Rather, it must be that the Prozdor referred to there refers to the outer area (before the baby comes out), and Prozdor here refers to the thickness of the thighs that cover the uterus when it is between the thighs, as Rashi explains. This is why the baby is not considered born just because its head is outside of the uterus (as this thickness stops it from appearing to just yet).

Implied Question: There is not a difficulty in the fact that Prozdor means two different things. (Where else do we see the same word indicating two different things?)

Answer: We find a similar thing in Bechoros (20a), as Rebbi Yehoshua says there that "Tinuf" - "being dirty" is a clear sign of having a baby (animal). This is not similar to the Tinuf that is mentioned in Nidah (29a), where the Gemara says that most women who give birth have Tinuf.

Explanation: This is even refers to the part that was inside the animal when it was slaughtered.

Question: How do we see from the Mishnah later (77a) that when a head comes out it is considered born? Perhaps this is just a decree that if some of the placenta comes out it is forbidden lest we permit a case where most of it came out?

Question (cont.): We find that we use to push aside an answer in Bava Kama (11a). The Gemara there says regarding Rebbi Elazar's statement, what is the novelty? (The Gemara attempts to answer) It seems that it is that there cannot be a small amount of placenta that comes out with a child being born. (The Gemara asks) We already learned this in the Mishnah that says that a small amount of placenta that comes out etc.

Answer: If the head coming out would not be considered giving birth there would be no reason to make a decree, being that it would never be possible in a case where a small amount of the placenta came out that there would be the significant status of a birth.

Implied Question: One cannot ask from here (the Mishnah on 77a) on Shmuel who says in Bechoros (46b) that the head of a Neifel does not exempt another child from being the Bechor. One would think that we only see from this Mishnah that this is true regarding an animal, not regarding a person (unlike Shmuel).

Answer: The second part of the Mishnah states that just as there is a sign of a child being born to a woman, there is a sign of a baby being born to an animal. This implies that it is referring to the placenta being the sign of a child.

Question: What is more obvious by one than by the other (that the rule must be said that their signs are similar)?

Answer: The Mishnah says in Nidah (25a) that regarding a woman, a tiny fetus (that the woman passed, see the commentaries there for the parameters of such a thing) is a sign of a child. This is why our Mishnah points out that even though a small fetus is not a sign that applies by an animal, it is similar in the laws regarding a placenta to a woman. (See also Mishnah in Bechoros 19b.)

Explanation: According to the Rabbanan who permit a camel in the womb of a cow even when it is born, they do not require a Pasuk to permit it with the slaughtering of its mother, as it is should not be worse inside the mother than when it is outside the mother. This is why the Gemara said this according to Rebbi Shimon. According to the Rabbanan, it is used for a different teaching.

Implied Question: One cannot say that this Pasuk is required to forbid an image of a pigeon, as the Gemara later says, "hooves are required, and this does not have hooves."

Answer: According to Rebbi Shimon, even though he does not have an extra Pasuk to teach this, the Gemara later implies that he also would forbid an image of a pigeon.

Proof: This is apparent from the Gemara later (69b). The Gemara asks, why isn't the image of a pigeon permitted? In other words, it should be permitted due to the verse, "From all in an animal." The Gemara answers, we require that the baby animal have hooves, and it does not.

Proof (cont.): The Gemara then asks, why don't we forbid an animal without split hooves if it is in the womb of a cow? The Gemara answers that the Pasuk says, "(any) hooves in an animal you should eat."

Proof (cont.): This question is only according to Rebbi Shimon. According to the Rabbanan, being inside (the animal) is not worse than being outside as we have explained.

Proof (cont.): This indicates that the image of a pigeon according to Rebbi Shimon is forbidden, even without a special Pasuk stating so. This is because there is no hoof or hooves on this pigeon. This is despite the fact that we say in our Gemara (68b) that we require the Pasuk "hoof" and "hooves" for the teachings regarding the place that was cut and a baby animal that does not have split hooves.

Proof (cont.): Similarly, according to the Rabbanan we do not a Pasuk to forbid the image of a pigeon. Rather, this extra Pasuk must be used for a different teaching. Even so, the Beraisa in our Gemara that says that if it retracted a hoof you could eat it must be only according to Rebbi Shimon.

Question: This is difficult. According to (Ula's statement in the name of) Rebbi Yochanan, the Beraisa regarding it retracting its hoof should be difficult, as it quotes two Pesukim. One teaches us about the place that was cut, and one teaches about the limb itself. Rebbi Yochanan, however, derives this from a different Pasuk!

Answer: The Gemara proceeds to ask a better question on (Ula) Rebbi Yochanan than the question from this Beraisa.

Explanation: Whatever went out of its walls (i.e. the body of the mother animal) becomes forbidden is similar to a Treifah that has no way of being permitted, as stated later.

Implied Question: We conclude that everything that goes back is permitted. (How, then, can we understand the Pasuk regarding a Treifah?)

Answer: We establish the Pasuk regarding Treifah as teaching a different teaching.

Question: The Pasuk regarding Chatas that says "Penimah" -- "inside" is referring to the fact that the Chatas did not go out of its walls. If it did, it must be burned.

Question: Why is this Pasuk necessary? We derive this lesson from the Pasuk of "Basar ba'Sadeh" - "meat in a field!"

Answer: One would think to derive Chatas from Ma'aser Sheini and Bikurim that are permitted (when they leave their walls). This is because Chatas is compared to them in the Pasuk (discussing Ma'aser Sheini) of "Lo Suchal Lechol b'Sha'arecha" - "you cannot eat in your gates" (Devarim 12:17).

Answer (cont.): This is as the Gemara states (regarding the rest of this Pasuk) in Makos (7a), "And your donations - this refers to a Todah and Shelamim. And your Bechoros- this refers to the firstborn of your cattle. And your sheep - this refers to a Chatas and Asham. And your pledges - this refers to an Olah." (The Pasuk "Penimah" teaches us specifically that Chatas is incomparable to Ma'aser Sheini in this regard.)

Question: Perhaps the Pasuk means that you cannot eat them in your regular "gates" (i.e. cities), but rather you should bring them to Yerushalayim to eat them if they have never yet been brought to Yerushalayim? It is not necessarily discussing Ma'aser Sheini that had been brought to Yerushalayim and was then taken out!

Answer: In Makos (19b see at length), the Gemara clearly understands that the Pasuk is referring to Ma'aser that had went into Yerushalayim and then left. This is because the Gemara says that one does not receive lashes for eating Ma'aser Sheini out of Yerushalayim unless the Ma'aser sees the walls of Yerushalayim.

Question: The Mishnah in Nidah (28a) says that if it came out cut up or feet first, most of it has to come out for it to be considered born. (Why is this asked by our Gemara? It is an explicit Mishnah!)

Answer: A woman is certainly considered impure from childbirth if most of the child comes out. However, we do not know from the Mishnah in Nidah (ibid.) that the rest (i.e. less than half) of the child that is inside is considered born.