Would the Bnei Yisroel have been permitted to trap arov on Shabbos?

Trapping on Shabbos

Question #1: Non-kosher Trapping

“Is it prohibited min haTorah to trap a non-kosher animal on Shabbos?”

Question #2: Watch your Trap!

“Can someone violate the melachah of trapping by closing the door of his house?”

Question #3: Anesthesia

“Is it permitted to anesthetize an animal on Shabbos?”



One of the 39 melachos forbidden on Shabbos is tzad, trapping. Although it might seem that this is an easy melachah to define, we will see that it presents some interesting issues. For example, some instances that we would never call “trapping” in English violate the melachah of tzad, and many things that we might consider to be trapping do not. For example, if a deer happens to wander into your house, and you close the door so that it cannot get free, you have just violated the Torah prohibition of tzad. On the other hand, if you close the door of a large cage with a small bird inside, you have not violated the melachah of tzad min haTorah. Tzad requires that the animal or bird is now easily usable, which is not the case of a small bird in a big cage. How one violates the melachah of tzad min haTorah might even vary from species to species, depending on how easy it is to catch.

Not all melachos are created equal

Let us examine another curiosity about trapping. Tzad is not a typical melachah. Most melachah actions make some type of physical and/or chemical change on their object, such as what happens when one cooks, sews, plants, or builds. Yet, tzad does not cause any kind of chemical or physical change to the animal that is caught. It is therefore among the minority of melachos that do not create any physical change. There are only a few other melachos in this category. A similar melachah is hotza’ah, carrying, which involves changing an item’s location, but no alteration to the item itself.

On the other hand, tzad creates a functional change – one makes the animal accessible to humans, whenever one may need it. Since the purpose of trapping is to harness a living creature, so that mankind can now access it, tzad can be viewed as a type of “acquisition” that makes the animal “usable” (Shu”t Avnei Neizer, Orach Chayim 189:7; however, see Biur Halachah 316:2 s.v. oh choleh, who may disagree).

Trapped species

The Torah prohibition of tzad is violated only when one traps a creature that is normally hunted by mankind (Shabbos 106b), meaning that people use its food or hide, or extract from it a medicine (Shabbos 107a) or dye (Shabbos 75a). An animal that meets these requirements is called bemino nitzod, literally, a species that is trapped. Catching an animal of a species that is not usually trapped or used by mankind, which is ein bemino nitzod, is not prohibited as a melachah min haTorah, but only because of rabbinic prohibition. Therefore, catching an animal whose species has no commercial value does not violate tzad min haTorah.

Non-kosher trapping

At this point, let us discuss the first of our opening questions: “Is it prohibited min haTorah to trap a non-kosher animal on Shabbos?”

If this is a type of animal whose hide is used, or from which either a dye or medicine is extracted, trapping it is prohibited min haTorah. According to the Chazon Ish (Orach Chayim 50:4 at end), someone who catches an animal to become a pet also commits a Torah violation of tzad. In his opinion, this use qualifies as bemino nitzod. On the other hand, what is the halachah if an animal is non-kosher, but non-Jews trap it for food? Is bemino nitzad for food limited to whether Jews eat it or not?

This appears to be the subject of a dispute between the rishonim, since Rashi (Shabbos 106b s.v. Hagizin) implies that trapping an animal for food is prohibited min haTorah only when it is a kosher species. On the other hand, the Ritva (Shabbos 106b) states explicitly that trapping a non-kosher species on Shabbos because a gentile intends to eat it is prohibited min haTorah – the fact that gentiles consume the non-kosher species qualifies it as bemino nitzod.

Catching mice

Early halachic authorities prohibit setting up a mousetrap on Shabbos (see Piskei Tosafos, Shabbos 17b, #62;  Magen Avraham 316:9). However, this does not mean that catching mice on Shabbos violates a Torah prohibition – it might be prohibited only miderabbanan. This is because it is unclear whether mice are considered bemino nitzod. If they are considered bemino nitzod, then catching them could sometimes be prohibited min haTorah. If they are not considered bemino nitzod, catching mice is prohibited only because of a rabbinic ruling.

Why would mice or rats be considered bemino nitzod? Although cats catch mice and rats for food, people in the western world are not interested in mice or rats for their food, leather or any other purpose. And the fact that a cat considers it bemino nitzod should not affect halachah.

However, one major authority, the Chayei Odom (30:7), rules that rats are considered bemino nitzod, since the hide can be used for leather, albeit of poor quality. In addition, according to the above-mentioned opinion of the Ritva, in a country where people eat rats, they qualify as bemino nitzod. Therefore, in China, where barbecued rat is a delicacy, it is bemino nitzod, according to the Ritva.

Catching lions

We will now move our discussion from the minute to the massive, from mice to lions. A lion is certainly considered bemino nitzod, since the hide would definitely be used, and, therefore, someone who successfully trapped a lion would violate tzad. However, lions are fairly powerful, so one would violate tzad only if it was, indeed, caught. The Gemara teaches that if a lion wandered into your house, closing the door does not constitute a Torah violation of trapping, since the lion will be able to break free. It is not considered tzad because one has not completed trapping it. One violates tzad for trapping a lion only by catching it in a cage or something similar that can keep it restrained (Shabbos 106b). Presumably, anesthesizing it or any other animal involves a melachah activity of tzad, since it is now “captured,”  and one can move it into an appropriate enclosure while the animal is anesthesized.

Thus we can now address the third of our opening questions:

“Is it permitted to anesthesize an animal on Shabbos?”

It seems to me that, if the animal qualifies as bemino nitzod, this is prohibited min haTorah, and, if it does not, it is prohibited miderabbanan.

Catching bees and wasps

Having discussed both mice and lions, let us move from land creatures to flying ones. Catching bees on Shabbos is prohibited because of a rabbinic prohibition, but not min haTorah (Beitzah 36b), for an interesting reason. Most beekeeping businesses pay their bills either by renting the bees for pollination of crops or by selling the honey. In either way, bees are “used” commercially by allowing them to roam wild – thus, they are never really “trapped” for use by man (Shu”t Avnei Neizer, Orach Chaim #189:21).

In an article I wrote entitled “Wanted Dead or Alive,” I discussed whether on Shabbos one may catch creatures, such as wasps and mosquitoes, that most of us consider a nuisance.

Catching itself

The Gemara (Shabbos 107a) describes what seems to be a very strange case. If a bird flies into your sleeve or garment on Shabbos so that it is now effectively caught, one is not required to release it. In this instance, the bird is considered to have trapped itself, and there is no requirement to let it go. However, one must be careful not to move it directly on Shabbos, since it is muktzeh.

Not always caught

Sick animals

On the other hand, catching a deer or any other animal that is sick, lame or injured to the extent that it is unable to flee does not involve a Torah prohibition of tzad. Since the animal can be obtained with little effort, it is considered already caught and already available for man’s possession (Tosefta, Shabbos Chapter 13:4; Gemara Shabbos 106b; Rambam, Hilchos Shabbos 10:24). Similarly, it is not prohibited min haTorah to catch a newborn animal that is not yet strong enough to flee (Beitzah 24a). It is also not a Torah prohibition to catch a snail, since they are so slow that they are considered caught (Tosafos Rid, Chagigah 11a).

Domesticated animals

There is no melachah min haTorah involved in catching an animal that is already cultivated, such as domesticated chickens or geese (Shabbos 107a; Rambam, Hilchos Shabbos 10:24). However, if the animal breaks free, catching it is prohibited miderabbanan. This is also germane to catching a caged pet that broke free. What can one do if one’s favorite parakeet escaped from its cage on Shabbos? Because of space considerations, we will need to leave the details of this topic for a different time (see Magen Avraham 316:26).

Locking the door

With this background, we can explain some of the following laws concerning meleches tzad. The Mishnah (Shabbos 106b) states that if a deer entered a house, it is prohibited min haTorah to close the door, because this traps the deer. Similarly, it is prohibited min haTorah to sit in the open doorway, because doing so also traps the deer (Mishnah Shabbos 106b). However, once someone is blocking the deer’s excape path, it is permitted for a second person to position himself in such a way that the deer will remain trapped even after the first person gets up (Shabbos 107a). To quote the Rambam, If the first person sat in a way that he closed off the deer’s exit, and then a second person sat next to him, even if the first one later gets up, the first person desecrated Shabbos and the second one did not do anything. He is permitted to remain in his place until Shabbos is over and then seize the deer (Hilchos Shabbos 10:23). The reason why this is permitted is because once the first person caught the deer, it is permitted to keep it captured (Mishnah Berurah 316:23, 24).

Similarly, if someone closed the door and thus caught the deer, a second person may now lock the door to make sure that no one mistakenly opens the door, which will free the deer (Rav, Shabbos 106b; Rema, Orach Chayim 316:5). These acts are permitted even miderabbanan.


Rav Hirsch (Shemos 35:2) explains that whereas other melachos demonstrate man’s mastery over the physical world, carrying demonstrates his mastery over the social sphere. Most melachos show man’s mastery over the world by the way man changes them. In the case of tzad, it is man’s showing mastery of the animal world by demonstrating his potential ownership. Rav Hirsch further notes (Shemos 20:10) that people assume that work is prohibited on Shabbos in order to make it a day of rest. He points out that the Torah does not prohibit doing avodah, which connotes hard work, but melacha, which implies purpose and accomplishment. Shabbos is a day on which we refrain from altering the world for our own purposes. The goal of Shabbos is to allow Hashem’s rule to be the focus of creation, by refraining from our own creative acts (Shemos 20:11). We thereby demonstrate and acknowledge the Creator of the world and all it contains.