QUESTION: The Gemara discusses the case of "Mechazeres," an animal that walks in Reshus ha'Rabim and turns its head and eats from food placed in Tzidei Reshus ha'Rabim or in someone's private field adjacent to Reshus ha'Rabim. According to the Gemara's first version, Rav and Shmuel disagree about the Halachah in this case. Rav maintains that the owner is liable even though the animal is standing in Reshus ha'Rabim. Shmuel maintains that the owner is exempt since the animal is in Reshus ha'Rabim. Rav and Shmuel agree that the owner is liable for damages that his animal causes when the animal leaves the center of the street in Reshus ha'Rabim and entirely enters the Tzidei Reshus ha'Rabim.

According to the Gemara's second explanation, Rav and Shmuel agree that the owner is liable for "Mechazeres." They disagree about the law in the case of an animal that ate food placed in a part of someone's property which he designated for public use.

1. Why should one be liable for damages caused by his animal that turns its head and eats food in the Tzidei Reshus ha'Rabim? One is liable for Shen only when the damage is done in the Reshus of the Nizak, the private property of the victim. Tzidei Reshus ha'Rabim is not the private property of the Nizak.

RASHI on the Mishnah (19b, DH mi'Tzidei) explains that the owner is obligated because of Keren. However, if this is a case of Keren, why is this case included in the Mishnah which discusses Shen, and why does the Mishnah rule that the owner pays "Mah she'Hizikah," which implies that he pays Nezek Shalem? Also, why do Rav and Shmuel agree that if the entire animal is standing in Tzidei Reshus ha'Rabim the owner is liable? Why should this be considered Keren?

2. On the other hand, if the damage of "Mechazeres" is considered Shen, why should the owner be liable when the damage is not done in the Reshus ha'Nizak? Moreover, why should "Mechazeres" be different from the case of an animal that eats food from atop another animal in Reshus ha'Rabim, in which case one is liable according to Ilfa (20a)? Why does Shmuel here say that one is exempt? (The Gemara on 21b says that Shmuel may agree with Ilfa's ruling.)

3. Finally, what is the difference between the case of "Mechazeres" and the case of "Misgalgel" (20a)? Rebbi Zeira inquires about the Halachah in a case of an animal standing in Reshus ha'Rabim that rolls a bundle of grain from a Reshus ha'Yachid into Reshus ha'Rabim. Is the owner liable because the animal rolled the food from Reshus ha'Yachid, or is he exempt because it ate the food in Reshus ha'Rabim? According to Shmuel who says that "Mechazeres" is exempt, even if one takes into account where the animal was standing (i.e. Reshus ha'Rabim) at the time it removed the food from Reshus ha'Yachid, the owner still should be exempt since only the animal's head was in Reshus ha'Yachid, and that is a case of "Mechazeres" according to Shmuel! (GILYON in Shitah Mekubetzes)

ANSWERS: Rashi seems to contradict himself with regard to which Av Mazik is involved in the act of "Mechazeres." In the Mishnah (19b), Rashi explains that when the animal eats from Tzidei Reshus ha'Rabim, it is an act of Keren. This implies that he understands "Mechazeres" to be a form of Keren, and that it is not the normal way that an animal acts. However, Rashi (21a, DH Kuli Alma Lo Pligi) explains that those who rule that one is liable for "Mechazeres" explain that the animal should not have turned its head to the side (because the area to the side is not a public area). Since Rashi writes that the animal "should not" have turned its head rather than "it is unusual" for the animal to turn its head, he implies that "Mechazeres" is not Chayav because of Keren but because of Shen.

TOSFOS and TOSFOS RABEINU PERETZ provide the answer to the apparent contradiction. They explain that Rashi wrote two different explanations for this Sugya. In his first explanation (Mahadura Kama), Rashi explained (both in the Mishnah and on 21a) that one is liable for "Mechazeres" because it is a form of Keren. This initial explanation of Rashi is preserved in the words of Rashi on the Rif and in the words of RABEINU YEHONASAN MI'LUNIL (21a). Rashi later changed his mind and decided that "Mechazeres" is a case of Shen, and he modified his commentary (on 21a) accordingly. (There are a number of instances in Bava Kama where parts of Rashi's Mahadura Kama and Mahadura Basra appear together in the text of Rashi; see Insights to 18:1.)

Accordingly, there are two ways to learn the Sugya of Mechazeres, as follows:

(a) According to Rashi's first Lashon, "Mechazeres" is a form of Keren, because it is unusual for an animal walking through Reshus ha'Rabim to put its head into an adjacent Reshus ha'Yachid. It seems from Tosfos (DH uv'Mechazeres) and other Rishonim that according to this explanation of Rashi, even when the entire animal enters Tzidei Reshus ha'Rabim the owner is still liable because of Keren and not because of Shen. Just as it is unusual for an animal to put its head into an area adjacent to Reshus ha'Rabim, it is even more unusual for an animal to leave Reshus ha'Rabim entirely. Therefore, Shmuel agrees that when the animal stands entirely in Reshus ha'Rabim and eats there, the owner is liable because of Keren. (The ROSH, however, as cited by the Shitah Mekubetzes, gives a different explanation for Rashi's words in the case of an animal that enters Tzidei Reshus ha'Rabim.)

Similarly, according to the Gemara's second version of the dispute between Rav and Shmuel, according to which they argue about a person who designates part of his property for the use of the public, the dispute revolves around whether it is considered unusual for an animal to enter such an area that is adjacent to Reshus ha'Rabim (and is, therefore, Keren), or whether it is not unusual (and is, therefore, Shen).

According to this approach, it is clear why one is liable for "Mechazeres" in Tzidei Reshus ha'Rabim even though the damage was not done in the personal property of the Nizak (because one is liable for Keren and not Shen). It is also clear that the discussion of the Gemara here is unrelated to the question of Ilfa (regarding an animal that stretched its neck and ate off of the back of another animal) and is also unrelated to the question of "Misgalgel," since the Gemara is discussing obligations of Keren and not of Shen.

Why, though, does the Mishnah discuss obligations of Keren in the midst of the Halachos of Shen? The answer is that it discusses Keren for the same reason that it discusses the Halachah of an animal that eats Kesus or Kelim; the Mishnah limits the applications of the Chiyuv of Shen. When the Mishnah says that one must pay "Mah she'Hizikah" with regard to an animal that eats from Tzidei Reshus ha'Rabim, it does not mean that the owner pays in full but that he pays in proportion to the full damage (i.e. either Chatzi Nezek or Nezek Shalem), and not just what it benefited (see Insights to 20:1).

(b) The other Rishonim, as well as Rashi himself in his Mahadura Basra, chose to explain that one is liable for "Mechazeres" because of Shen and thus pays Nezek Shalem. Why, though, should one be liable for "Mechazeres" if the animal eats an object in Tzidei Reshus ha'Rabim? The animal is standing in Reshus ha'Rabim!

They explain that Rav and Shmuel argue about whether the exemption from paying for damages of Shen in Reshus ha'Rabim depends on where the animal is standing or where the food that it eats is resting. Rav maintains that as long as the food is in a Reshus ha'Yachid the owner of the animal is liable. Shmuel maintains that since the owner of land adjacent to Reshus ha'Rabim realizes that animals will be walking near his property and can easily reach over and eat food that is on the edge of his field, he should not keep his food there. Since people do not want to limit the use of Reshus ha'Rabim they forgo claims for any damages to objects that are either in Reshus ha'Rabim or that are in parts of Reshus ha'Yachid that are adjacent to Reshus ha'Rabim (see Rosh 1:1). (Rav does not accept this reasoning because he maintains that people who walk their animals in Reshus ha'Rabim are responsible for preventing their animals from putting their heads into fields that are adjacent to Reshus ha'Rabim.) Even Shmuel agrees that the owner is liable if the animal entirely enters the Reshus of the Nizak, or Tzidei Reshus ha'Rabim, because that is the normal case of Shen in Reshus ha'Nizak.

If the Chiyuv of "Mechazeres" is because of Shen, why is the owner of the animal liable when his animal eats from Tzidei Reshus ha'Rabim? At most, it should be like an animal that eats from Chatzer ha'Shutafin, in which case some Amora'im maintain that he is exempt (see 14a).

Tosfos here explains that the Tzidei Reshus ha'Rabim in front of every house that borders Reshus ha'Rabim is used exclusively by the owner of that particular house.

Tosfos Rabeinu Peretz explains that when one person places fruit in a particular part of Tzidei Reshus ha'Rabim, it becomes prohibited for any other person to bring his animal or food there. Therefore, that area is like the Reshus ha'Yachid of the Nizak as long as his food is there. (See NIMUKEI YOSEF as quoted in Insights to 14a.)

Why is this case different from Ilfa's case of an animal that reaches up and eats from the back of another animal in Reshus ha'Rabim? It is different because in the case of "Mechazeres" the animal ate food on the same level as the food in Reshus ha'Rabim. Since people expect such damages to occur more frequently, a case of "Mechazeres" might be more lenient than the case of an animal that eats from the back of another animal. On the other hand, the case of "Mechazeres" might be more stringent than the case of an animal that eats from atop another animal in Reshus ha'Rabim because in the case of "Mechazeres" the animal leaves the main walkway of Reshus ha'Rabim and eats from the side.

How is the argument between Rav and Shmuel, according to the Gemara's first version, different from the question of "Misgalgel" (20a)? There, Rashi explains that the question of "Misgalgel" is as follows: An animal standing in Reshus ha'Rabim takes an item from Reshus ha'Nizak and eats it in Reshus ha'Rabim. Is the owner's liability determined by where the item was taken from, is it determined by where the animal ate the item? From the Gemara's question it seems clear that even if the animal is standing in Reshus ha'Rabim and puts its head into Reshus ha'Yachid to take an object from there, it is considered as though the animal took the object from Reshus ha'Nizak since its head was in Reshus ha'Nizak when it removed the object. The animal is not considered to have taken an object from Reshus ha'Rabim merely because its feet are in Reshus ha'Rabim at the time. This seems to contradict Shmuel who says that one is exempt for "Mechazeres" because the damage follows where the place where the animal's head is.

The GILYON cited by the Shitah Mekubetzes answers that Rebbi Zeira, who questions what the Halachah would be in a case of "Misgalgel," follows like the Gemara's second version of the Machlokes between Rav and Shmuel. According to that version, even Shmuel agrees that what matters is where the head of the animal is and not where the feet are.

Alternatively, the question of "Misgalgel" does not involve an animal that puts its head into Reshus ha'Yachid and removes an object from there, but rather it involves an animal that entirely enters Reshus ha'Yachid and takes an item out to eat in Reshus ha'Rabim.