Wanted Dead or Alive

Question #1: Getting Rid of those Bugs!

“May I trap or kill mosquitoes, bees, or wasps on Shabbos?”

Question #2: Hanging from the Lowest Tree

“I forgot to hang the flypaper before Shabbos. May I do it on Shabbos?”

Question #3: A Charming Shabbos

“May a snake charmer work on Shabbos?”

Answer: Catching or dispatching

We have all been in the following uncomfortable situation: Sometime during Shabbos, a mosquito appears in our vicinity seeking to earn its living. Although we realize that this creature requires its sustenance, we are not eager that we, our children or our guests should become mosquito fodder, even just as a minor donor. Are we permitted to trap or kill the mosquito?

Trapping living things, tzad, was an action necessary for acquiring some of the materials used to build the Mishkan, and is one of the 39 melachos, categories of prohibited activity on Shabbos (Mishnah Shabbos 73a and Rashi ad loc.). Killing living things also violates the melachos of Shabbos, a topic that we discussed last week. Here, we discuss many pertinent principles of Shabbos and some details of the melachah of tzad.

Shabbos nomenclature

When discussing what one may or may not do on Shabbos, the Mishnah and Gemara use three terms: (1) chayov, punishable, when a particular act constitutes melachah, meaning that it desecrates Shabbos by violating a Torah law; (2) patur, exempt, meaning it does not violate a Torah law, and (3) mutar, permitted, when an act may be performed on Shabbos. We will discuss the middle term, patur, which states that a particular forbidden act does not violate Torah law. This term usually indicates that the act is prohibited due to rabbinic sanction, but  sometimes the Sages permitted such acts. But first we will explain what makes performing a forbidden activity patur?

Meleches machsheves

The Gemara (Chagigah 10b; Bava Kama 26b; Kerisus 19b) teaches that the Torah prohibited only something that can be categorized as meleches machsheves, which can perhaps be translated as premeditated melachah. An obvious example of meleches machsheves would be trapping an animal to obtain its hide or meat. Similarly, someone who digs a hole to plant the base of a tree violates the meleches machsheves of choreish, plowing, and one who picks a fruit performs a meleches machsheves of kotzeir, harvesting.

Meleches machsheves is often explained by what it is not. Following that approach, I will provide three categories of labor that are exempt from being defined as desecrating Shabbos min haTorah, because they do not qualify as meleches machsheves, at least according to some opinions.


In general, an act constitutes meleches machsheves only when its direct result is beneficial. This means that an action that is inherently destructive does not violate Shabbos min haTorah, even when one needs the result. For example, digging a hole in the ground when one needs the earth but not the hole is defined as a destructive activity and prohibited only miderabbanan. The dug hole itself is a negative development, rendering the burrowing to be mekalkeil, not prohibited min haTorah, but only because of rabbinic injunction. However, digging a hole to plant or to create a posthole results in a positive benefit and is indeed prohibited min haTorah, since one wants the hole in the ground.

Bemino nitzad

Here is a second example of meleches machsheves that is particular to the melachah that we are discussing, tzad. The tanna’im (Shabbos 107b) dispute whether it is prohibited min haTorah to ensnare a creature that mankind does not typically use, such as a scorpion or a flea, which is called ein bemino nitzad, literally, a species that is not trapped. The halachic conclusion follows the lenient opinion, ruling that tzad applies only to a species that is bemino nitzad, commonly trapped, so that mankind can benefit from it. For example, a species that is eaten, from whose body a medicine is extracted, or whose hide is used as leather qualifies as bemino nitzad. The halachic authorities discuss whether trapping an animal for scientific research or so that one can have it as a pet makes the animal bemino nitzad (Rambam, Hilchos Shabbos 10:21; Chazon Ish, Orach Chayim 50:4 at end).

However, a species that is caught only because it is an annoyance has the status of ein bemino nitzad.

Why is this true? The purpose of trapping is to harness a living creature so that mankind can use it. Thus, tzad is a type of acquisition (see Shu”t Avnei Neizer, Orach Chayim 189:7; Biur Halachah, 316:2 s.v. Oh Choleh). However, trapping a creature that mankind does not generally use is not acquiring these creatures, but distancing them from potential victims. Therefore, most opinions conclude that trapping a species that is ein bemino nitzad does not violate the melachah of tzad, and is prohibited only because of rabbinic injunction. Thus, since flies are ein bemino nitzad, catching them would not violate a Torah prohibition. Hanging flypaper on Shabbos would still involve a rabbinic prohibition and it is similarly prohibited to set up a mousetrap on Shabbos (Magen Avraham 316:9; see Piskei Tosafos, Shabbos 17b #62).

By the way, many authorities consider mice to be bemino nitzad, since there are places in the world where their hide is used (Chayei Odom 30:7). There is also a dispute whether a non-kosher species harvested only as food is considered bemino nitzad (Ritva, Shabbos 106b; Nimla Tal, Meleches Tzad #37).

Melachah she’einah tzerichah legufah

Many authorities rule that another category of activity — Melachah she’einah tzerichah legufah, literally, an act not needed for its purpose — is not prohibited min haTorah because it is not considered meleches machsheves. In fact, there is a dispute among tanna’im whether a Melachah she’einah tzerichah legufah is prohibited min haTorah or only miderabbanan. Whereas Rabbi Yehudah contends that Melachah she’einah tzerichah legufah is prohibited min haTorah, according to Rabbi Shimon, these acts are prohibited only by virtue of rabbinic injunction.

What is a Melachah she’einah tzerichah legufah? Among the rishonim, we find differing opinions as to exactly how to define this term, and there are many instances where a dispute in halachah results. Since this complicated question is a bit tangential to our topic, I am going to present only one approach. According to Tosafos (Shabbos 94a s.v. Rabbi Shimon) and the Rivash (Shu”t Harivash #394), Rabbi Shimon contends that the 39 melachos are prohibited min haTorah only when performed for a goal or purpose similar to the reason why this melachah was done when constructing the Mishkan. However, performing a melachah to accomplish a purpose other than that for which this melachah was performed in the Mishkan qualifies as a Melachah she’einah tzerichah legufah. This means that it is prohibited only miderabbanan, according to Rabbi Shimon and those who rule like him.

Here is an example: Removing an item that has a bad odor from a reshus hayachid, an enclosed area, into a reshus harabim, an open area meant for public use, is a classic case of Melachah she’einah tzerichah legufah. Although moving something from a reshus hayachid into a reshus harabim constitutes the melachah of carrying, moving the foul-smelling item from a house to a reshus harabim does not constitute a melachah min haTorah, according to Rabbi Shimon, because the purpose of the carrying when building the Mishkan was to relocate the item to a new place. However, when removing a foul-smelling item, there is no significance attached to the place to which the item is moved; one’s goal is only to distance it from its current location. The public area does not constitute the goal of one’s act; rather, it is merely a convenient place to deposit unwanted material. For this reason, Rabbi Shimon contends that this act was not prohibited by the Torah, but only by the Sages. On the other hand, Rabbi Yehudah considers Melachah she’einah tzerichah legufah as conforming to the definition of meleches machsheves and prohibited min haTorah.

Although most rishonim conclude that the halachah follows Rabbi Shimon that Melachah she’einah tzerichah legufah is prohibited only because of rabbinic injunction, the Rambam and others rule, according to Rabbi Yehudah, that Melachah she’einah tzerichah legufah is prohibited min haTorah.

When exempt is permitted

There is a passage of Gemara that reflects both on our opening question and on a different aspect of the melachah of tzad. “Shemuel said: Whenever the Mishnah states that something is patur when performed on Shabbos, the activity is prohibited [because of a rabbinic injunction], with the exception of the following three instances, when patur means that the activity is permitted. The first case discusses catching a deer, the second is catching a snake and the third is lancing a boil” (Shabbos 3a; 107a, as explained by Tosafos, Shabbos 3a s.v. Bar). Shemuel proves from Mishnayos that, in these three instances, the acts are permitted (Shabbos 107a). The first two of these cases educate us to understand what constitutes the melachah of trapping. (The case of lancing a boil involves a different topic that we will leave for a different article.)

What are the first two cases presented by Shemuel? The first situation is when a deer entered a building, and someone sat in the doorway of the building, thereby preventing the deer’s escape. When that person sat down, he trapped the deer and therefore performed the melachah of tzad. This is true, even if he was not involved in coaxing the deer into the building. The Mishnah (Shabbos 106b) then states that if a second person sits alongside the first in a way that the deer’s escape is still blocked, even when the first person gets up, the second person has not desecrated Shabbos. This is because the second person did not trap the deer but merely guaranteed that a captured animal remains in captivity. Although the Mishnah says that the second person is patur, Shemuel explains that one may lechatchilah sit down alongside the first person, even if one’s intention is to keep the deer trapped when the first person gets up. This explains a different aspect of tzad — the melachah is making the animal available for human use, but once it is already trapped, there is no further violation in keeping it under human control.

The second case is based on two different mishnayos. One Mishnah (Shabbos 107a) permits catching a scorpion, so that it doesn’t bite, and another states that catching a snake to prevent it from biting does not violate Shabbos min haTorah, whereas catching it for medicinal uses does (Eduyos 2:5). Tosafos proves that both Mishnayos that permit tzad to protect someone are discussing creatures whose bite is painful, but not life-threatening, pikuach nefesh (Tosafos, Shabbos 3a s.v. Bar). Were the Mishnah discussing a creature whose bite is life-threatening, it would be obvious that one may kill it, because of the general rule that actions necessary to protect life supersede Shabbos and almost all other mitzvos.

Shemuel ruled that although catching non-dangerous creatures is ordinarily prohibited on Shabbos, since this involves only a rabbinic injunction the Sages permitted it under extenuating circumstances.

Why is the act of trapping non-dangerous creatures considered only a rabbinic injunction? We have already presented two possible reasons. The first is because of the principle of Melachah she’einah tzerichah legufah, since one has no interest in capturing a snake or a scorpion (Tosafos op. cit.). The second reason is that one is not catching these species to make them available for human use, which is an essential component of the melachah of tzad (Avnei Neizer, Orach Chayim 189:7; Biur Halachah, 316:2 s.v. Oh Choleh).

Mosquitoes versus snakes

Although we have discovered that one may catch snakes and scorpions that are not life-threatening, this does not tell us whether one may trap mosquitoes, bees or wasps. Although the sting or bite of these species is indeed painful, it is not usually as painful as a snake or scorpion bite. Thus, it might be that Chazal did not permit catching mosquitoes, bees or wasps.

We can presumably derive the answer from the following passage of Gemara:

“Someone who trapped a flea on Shabbos, Rabbi Eliezer rules him liable for desecrating Shabbos min haTorah, whereas Rabbi Yehoshua rules that his desecration of Shabbos was only of a rabbinic ordinance” (Shabbos 107b). The Gemara explains that this dispute is dependent on an issue that we discussed earlier. Does one desecrate Shabbos min haTorah if he traps a species that is not usually trapped? Rabbi Eliezer rules that he does, whereas Rabbi Yehoshua rules that he does not. Thus, it appears from this Gemara that although Shemuel proved that it is permitted to trap a scorpion, even of the non-deadly variety, one cannot trap a flea, which is considered only as causing discomfort.

Three types of varmints

We can, therefore, divide the different types of unpleasant biters and stingers into three categories:

1. Those that are potentially life-threatening to people. In this instance, if there is even the slightest possibility of danger, one may kill or catch them on Shabbos.

2. Those whose bite will be very painful, but there is no life-threatening danger. These may be trapped on Shabbos, provided that one’s intent is only to save people from harm (Rambam, Hilchos Shabbos 10:25). However, it is forbidden to trap if one intends to use the insect, reptile or arachnid. (Modern biology categorizes spiders and scorpions as arachnids, because they have eight legs, are carnivorous and are wingless. If we want to categorize insects and arachnids together, we should use the word arthropods, but that still excludes snakes and other reptiles. So, for most of this article, I have simply used the word creatures. My apologies to the scientists who are reading this.)

3. Those whose bite will be unpleasant, but not highly painful. In this instance, there is a dispute among the rishonim. Tosafos and the Rosh quote from an earlier baal Tosafos named Rav Poras that, if one sees that an insect may bite him, he is permitted to remove the insect. When the insect is not so close to him, he may brush the insect off, but he may not trap it.

Not all authorities accepted Rav Poras’ approach. The Mordechai (#402) quotes Rav Yehudah Gaon that he noticed that the “elder rabbis” did not trap fleas, even when they were on their skin. The Beis Yosef, however, contends that even Rav Yehudah Gaon accepts the ruling of Rav Poras, but that he himself practiced this as a personal chumrah, not as the required halachah that he would rule for others. There are other rishonim, however, who certainly disagree with Rav Poras and prohibit trapping mosquitoes, even when they are on your skin, since they are only a discomfort (Meiri, Shabbos 107b).


The consensus of halachic authorities follows Rav Poras, although there is a dispute among them whether it is permitted to catch the insect only when it is actually biting (Shulchan Aruch, Orach Chayim 316:9; Bach) or whether one may remove the insects even when they are in close proximity (Taz 316:8; Magen Avraham 316:18; Elyah Rabbah). The Mishnah Berurah (316:37) concludes that when one can brush off the insect, he should not rely on the heter of trapping it, but he implies that one may trap the insect if brushing it off will not suffice.


At this point, let us take a fresh look at our original questions:

“May I trap mosquitoes, bees, or wasps on Shabbos?”

The answer is that if the insect is about to attack someone, one may trap it. One may also trap it if its sting or bite is very painful, and certainly if it is potentially dangerous.

May one hang flypaper on Shabbos? The answer is that one may not.

“May a snake charmer work on Shabbos?” If one is not intending to use the snake, it is permitted. This is all the more so if the snake is dangerous.

In conclusion

Rav Samson Raphael Hirsch (Shemos 20:10) notes that people mistakenly think that work is prohibited on Shabbos, to ensure that Shabbos is a day of rest. He points out that the Torah does not prohibit doing avodah, which connotes hard work, but melachah, which implies purpose and accomplishment. We certainly see this idea borne out by the ideas of meleches machsheves, which denote the purpose of the action, and have no correlation at all to the amount of energy expended. The goal of Shabbos is to allow Hashem’s rule to be the focus of creation by our refraining from our own creative acts (Rav Samson Raphael Hirsch Commentary to Shemos 20:11).

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.