The following chapter will discuss the laws of trapping, killing and injuring creatures on Shabbos. Both trapping, killing or injuring an animal are principal Shabbos prohibitions. At times it is only Rabinically forbidden and thus allowed to be done in a scenario of danger. Other times even when Biblically forbidden to be done it is allowed to be done if there is a life threatening situation, as will be explained in this chapter.
1. The Principal Prohibition:
2. The Biblical Prohibition:
The Biblical prohibition of trapping only applies if all the below conditions are met:
A. One completely traps the creature:
One is only liable for [Biblically transgressing] it if the trapped [animal or fish] does not lack any further trapping after this [current] trapping, meaning that he has trapped it to an area where he can easily grab it. It goes without saying [that one transgresses the Biblical prohibition of trapping if] one set up a trapping mechanism which trapped it [simultaneously], as once in the trap one does not need to do any further schemes in order to grab it.
An example: Therefore if one chased a bird into a house which is closed or into a roofed shack which is sealed from all sides, and then closed the door before it, or if one chased after an animal until he entered it into a house or into even an unroofed shack or into a garden or courtyard and then closed the door before it, he is [Biblically] liable, as long as that the house or shack is not large enough to the point that one [still] needs to scheme methods of how to grab hold of the bird or animal [that is in there].
[However] so long as the house or shack is large enough to the point that one is not able to reach and grab the bird or animal in a single chase due to it running away from him and he thus needs to chase after it a second time, then they are still [considered to be] lacking being trapped and one is [thus] Biblically exempt.
Trapping a sparrow: One who traps a sparrow which is a type of bird that dwells in a house just like in a field [meaning that] it knows how to escape [being caught, by flying] to all the corners of the house and (it is thus called Drur which means a dwelling as it dwells in all places) then one is not liable until he chases it into a tower which it can be trapped in which is a tower that is not very large, and rather [is small enough that] one can grab it without any further schemes.
Trapping a lion: One who traps a lion is not liable until he enters it into a cage that it can be restrained in.
Trapping an animal which needed further trapping: One who traps [an animal or bird] from an area where it was still lacking further trapping there, is liable.
Trapping an animal which did not need further trapping: See cases permitted to trap.
Removing a fish from a river or pool of water: One is exempt from the trapping prohibition if he took out a fish from an area that it was already trapped in and was not lacking any further trapping at all, such as for example [the fish was in a] bucket or barrel (see chapter 497[Halacha 1]). However if one took it out from an area where it was lacking further trapping, such as for example [taking a fish out from] a river or pool, then even if he immediately returned it into water that is in a vessel, [nevertheless] he is liable for trapping. [Furthermore] even if one did not catch it with his hand at all, but rather simply draw it out of the river with a bucket of water, then he is liable for trapping as when [the fish] is inside a bucket it does not lack any further trapping.
B. One traps for self use as opposed to trapping to prevent injury:
One who traps is not liable unless he has a need for the actual body of the trapped item. Nevertheless one who casually traps species of animals, birds, and fish, is liable, as they are generally trapped for need of their body or skin. Similarly one who casually traps one of the eight rodents mentioned in the Torah is liable as they are generally trapped for need of their skin and not to save oneself from injury being that it is not common for them to injure.
However one who traps one of the other creeping creatures [which are commonly trapped to prevent injury] is not liable unless he trapped them for a need, such as for a medicine and the like. However if he casually trapped them, then he is exempt [from liability] being that they are generally trapped in order to prevent injury, being that they commonly injure and not for their skin being that they do not have skin, and not for their bodies being that they are inedible and they are not generally [trapped] for medicine unless one explicitly intended [on trapping them] for this, and thus this [trapping] is an action which does not have a self use being that he has no need for the trapped item itself to which the [forbidden] action [of trapping] is being done to.
Other Opinions: [However] according to those opinions which say that even an action which is not done for its own use one is [Biblically] liable on
C. Trapping something which is not commonly trapped being that it serves no use:
The Biblical prohibition of trapping something only applies by a species that is [commonly] trapped, which means that it is common for the [people of the] world to trap this species that he is trapping.
For example, [trapping] species of animals and birds and fish [is liable because] it is common for the [people of the] world to trap these species. 
However if he trapped something which is a species that is not [commonly] trapped, such as for example wasps and flies and mosquitoes and the like of which it is not common for [people of] the world to trap these species being that they do not have any use, then even if one happened to trap them for a use, he is exempt [from Biblical liability].
D. The animal is not old or crippled:
An old, or crippled or exhausted deer: One who traps an item which is not lacking any further trapping, such as for example one trapped a deer which is crippled or old, or week due to exhaustion from doing strenuous activity, and [thus] it is not able to move from where it is, then [although] he is not liable nevertheless it is Rabbinically forbidden.
A sleeping or blind or sick deer: However one who traps a deer that is sleeping or is blind or is sick [and weak] due to a fever that has developed in his body, then he is liable because they are self trained to escape when they feel the hand of a person, and are thus [considered to be] lacking further trapping.
E. The trapping was done singlehandedly if possible:
Single person trapped: A deer which entered on its own into a house and someone closed the door in front of it, then even if he did not lock the door with a lock but rather just pressed it closed in a way that the deer is guarded through this that it not be able to escape, then he is liable being that this is its trapping.
Two people trapped together and can be done alone: If two people closed it then they are exempt [from liability] as [the rule is that] any action which can be done alone and was done by two people, then they are exempt because it was not done in the usual method that it is done in during the week, as it is not usual at all to for [an action] which can be done alone to be done by two people.
If it cannot be done alone: [However] if one alone cannot close it and two people closed it then they are liable.
If one of the partners can do it alone: If one [of the two] is able to close it alone and the second is not able and they both closed it, then the one that is able is liable and the one that is not able is exempt being that [the one that is not able] is only considered an [unneeded] accomplice to the one that is able, and an [unneeded] accomplice has done a meaningless action.
This rule applies for all the [prohibited] actions of Shabbos.
F. The creature is not one’s pet or farm animal:
Animals and birds which are raised in a person’s property, such as one who breeds deer in his house or in his courtyard or geese and chickens and doves, then if one trapped them on Shabbos he is exempt [from liability] being that they are already [considered] trapped.
Wild pigeons which nest in ones property: However one who traps [wild] pigeons which reside on nests and high surfaces is liable because they are lacking further trapping as when a person comes to take them from their nest they are trained to escape and run away from their nest.
Domestic animals which have rebelled: All the above [allowances to trap domestic animals and birds] only apply if they have not rebelled, however if they have rebelled, [including] even a cow that rebelled, and it goes without saying [that it includes] wild natured animals and birds that have rebelled, then one who traps them on Shabbos is liable just like having trapped wild [non-domestic] animals and birds as these [animals and birds which have rebelled will] also, not enter into their cage at night.
Summary of the Biblical Trapping prohibition:
It is only Biblically prohibited to trap a creature on Shabbos if all the following seven conditions are met:
- The animal was previously not fully trapped and one now fully trapped it in a way that he does not need to further trap it.
- It is a creature which is commonly trapped [irrelevant to the reason why it is commonly trapped].
- The creature was trapped in order to use its body for a certain purpose, such as to eat or for its skin and the like, or if one casually trapped it but it is a type of creature which is generally trapped for the above purpose.
- The animal was not old, crippled or exhausted to the point that it could not escape.
- One is trapping it himself and not through a hunting dog, or trap that had already been set up.
- The animal was trapped by a single person, or by two people in a scenario that it required two people to trap.
- The animal is not a tamed pet or livestock and the like that has not rebelled.
It is Biblically forbidden to:
- Remove a fish from a river whether with ones hands or a bucket [or rod].
- Enter a lion into its cage.
- Grab a sick animal from outside.
- Trap a sparrow to an area that it needs no further trapping.
3. The Rabbinical prohibition of trapping:
It is Rabbinically forbidden to trap in any of the following cases:
Traps in a way that it still requires further trapping:Anyone who traps into an area where the trapped [animal or bird] is still lacking further trapping then although he is not liable [nevertheless] it is Rabbinically forbidden.
Trapping an animal which did not need further trapping: From an area that the [animal] does not lack any further trapping it is initially allowed to trap it on Yom Tov, although not on Shabbos due to the moving ‘[Muktzah] prohibition. [In addition] there are those which prohibit this [on Shabbos] also because of a Rabbinical trapping prohibition [which according to them applies even in this case].
Trapping a sick, old, blind, lame, etc animal: One who traps an item which is not lacking any further trapping, such as for example one trapped a deer which is crippled or old, or week due to exhaustion from doing strenuous activity, and [thus] it is not able to move from where it is, then [although] he is not liable nevertheless it is Rabinically forbidden. However one who traps a deer that is sleeping or is blind or is sick [and weak] due to a fever that has developed in his body, then he is liable because they are self trained to escape when they feel the hand of a person, and are thus [considered to be] lacking further trapping.
Creature is not commonly trapped: Although the Biblical prohibition of trapping something only applies by a species that is [commonly] trapped, while if he trapped something which is a species that is not [commonly] trapped, such as for example wasps and flies and mosquitoes and the like….., he is exempt [from Biblical liability], nevertheless, it is Rabbinically forbidden [to do so] even if one wants to trap them for no need at all and rather out of mere casualness.
One is trapping without intent to make use of the creature: Although any [forbidden] action which is not done for self use one is not liable on, [nevertheless it] is Rabinically forbidden.
One is unnecessarily trapping with two people: Although when two people trap together they are exempt [from liability] as [the rule is that] any action which can be done alone and was done by two people, then they are exempt [nevertheless it is Rabinically forbidden to do so].
It is Rabinically prohibited to trap a creature on Shabbos even if:
- One does not fully trap the creature to the point that one can grab it in a single chase.
- The creature is not commonly trapped being that it does not have a use.
- One is trapping it out of mere casualness, for no use at all.
- The animal is exhausted, or old or crippled to the point it cannot escape.
- One could have trapped it alone and rather did it together with another person.
- If the animal is already fully trapped, trapping it further is forbidden on Shabbos due to Muktzah, and according to some it also contains a Rabbinical trapping prohibition.
May one enter a creature from outside a house to inside the house if he leaves the door open, or leaves open another obvious escape route for the creature?
The Ketzos Hashulchan sides that this is completely permitted, and so is implied 316/5.
However the Mishneh Berurah doubts as to whether or not this is allowed.
May one trap an animal that is never commonly trapped and can never run away, such as a turtle and ant?
Rav Shlomo Zalman Aurbach states that there is no trapping prohibition involved in doing so, as the animal is considered already trapped.  However one may not move the turtle or ant with his hands due to the Muktzah prohibition.
Is there a prohibition involved in trapping humans, such as locking a child in his room, or a lunatic into his room?
There is no trapping prohibition involved in trapping humans. One may thus lock a child in his room if needed, and arrest a man on Shabbos who is trying to leave his wife an Aguna. However there are Poskim which question that perhaps the trapping prohibition applies to a child. Others forbid capturing a lunatic which would otherwise run away from society. In any event it is forbidden to arrest an individual on Shabbos [unless there is extreme reason to do so] due to the prohibition to mediate punishments on Shabbos, irrelevant of the trapping issue.
May one imprison a man who desires to leave his wife an Aguna? 
One may arrest a man on Shabbos who is trying to leave his wife an Aguna.
May one arrest a man who has perpetrated crimes against society, such as robbery, abuse, and bodily injury?
4. A mouse trap– Setting up a trap mechanism on and before Shabbos:
A. Setting up a trap from before Shabbos to trap on Shabbos:
It is permitted to begin a Melacha on Erev Shabbos close to dark even though one will not be able to finish it while still day, and it will thus consequently become complete on its own on Shabbos. Furthermore, even if it is a situation in which the vessel itself is doing the [entire] Melacha on Shabbos on its own, such as to spread traps for wild animals and birds and fish from before Shabbos, and [thus] having them become trapped on Shabbos, [it is nevertheless permitted] despite the fact that the trap is what is doing the action of trapping on Shabbos, being that the metal becomes tied and grabs the bird on Shabbos. Similarly the booby-trap which they spread [to catch] wild animals to capture them by their feet, in which when the animal touches [the trap] it jumps and attaches itself on its own [against the legs of the animal] and traps it [it is permitted to spread it before Shabbos].
B. Setting up a trap on Shabbos: 
Biblically: One who sets up a trap [on Shabbos] and while doing so an animal entered into it, he is liable. However if the animal entered into the trap afterwards, then he is exempt [from liability] because at the time that he set it up it is not [yet] known if it will trap or not.
Rabbinically: Nevertheless it is Rabbinically forbidden and therefore it is forbidden to set up mouse traps on Shabbos.
Summary- May one set up a trap on and before Shabbos?
Before Shabbos: Is permitted.
On Shabbos: Is forbidden. Doing so involves a Rabbinical prohibition.
May one move around a mouse trap from one room to another?
5. Hunting dogs:
On Shabbos: One who instigates a [hunting] dog [to chase] after an animal in order to trap it is exempt [from Biblical liability] but is Rabinically forbidden.
During the week: [Furthermore] even during the week it is forbidden to trap with dogs because [this symbolizes the actions of a] group of scoffers, and [one who does so] will not merit to participate in the joy of the Leviathan [feast].
Summary-May one go hunting with hunting dogs during the week?
No, as this is considered a sport of the scoffers. [Although for purposes of business there are sources which allow it.]
6. Un-trapping an animal on Shabbos
It is allowed for one to open ones house in front of a deer [which is trapped inside] in order for it to run and escape.
As well a deer which has entered into a trap one is allowed to release it from its trap on condition that one not move it [being that it is Muktzah].
Summary-May one un-trap an animal on Shabbos?
Yes as long as one does not move it in the process.
7. One who unintentionally trapped a creature:
Closing the door of one’s house when he does not know if an animal’s inside: One who locked [the door of] his house in order to guard it [from break ins] without the slightest knowledge that a deer had entered into the house and only afterwards did he find out, then it is permitted for him to leave the entrance locked until after Shabbos with intention to take the deer [after Shabbos], as when he locked his house he was allowed to do so being that he knew of no [existing animals in his home] and now when he discovers this he is not doing anything [new].
Closing the door of one’s house when he knows of animals inside: See Halacha 8!
Sat by the entrance and unintentionally trapped an animal: Similarly one who sat by the entrance without knowledge that a deer had entered his house and later discovered this then it is permitted for him to remain sitting there until after Shabbos being that now [upon the discovery] he is not doing anything [new].
A bird which flew into ones clothes trapping itself: Similarly one who had a bird enter under the wing of his clothing and consequently got trapped there, does not need to open for it an escape route and rather may guard it until Shabbos is over.
Summary-If one unknowingly did an action which trapped a creature must he let it out?
8. Closing the door of one’s house when he knows an animal or bird is inside:
The animal is trapped: If one had a deer bound up in his house and someone came along and also closed the door in front of it in order to add a [further form of] guarding onto the already existing [form of] guarding, and then afterwards the deer escaped from the ropes, we do not require the person to reopen the door being that at the time that he closed it he was allowed to do so and now he is doing nothing [new].
The animal is not yet trapped: If one knows that there is an [un-trapped] deer in his house then it is forbidden for him to close the door even if he does not at all intend to trap the deer but rather [just intends] to guard his house [from break ins], as the trapping [which comes as a result of his closing the door] is inevitable.
One may not close his windows or door even to protect his home from robbers if doing so will trap an animal or bird within his house.
May one do an action which will inevitably trap a creature if he does not intend to trap it?
No. For this reason one may not close his windows or door even to protect from robbers if doing so will trap an animal or bird within his house.
May one close the door of his house if he has a mouse or bird inside?
If there is another obvious escape root available for the bird or mouse then doing so is permitted. If not then it is forbidden.
9. Locking the closed door of a room which contains an animal:
If the doorway had already been closed by the door after the deer entered into the house, whether the door had closed on its own [and] whether one transgressed and closed it, it is permitted to lock it with a lock. As since the deer is already guarded in a way that it cannot escape, it is thus already currently trapped and when one thus locks it with a lock, although he is adding a further means of guarding to the guarding that there is currently, [nevertheless] this is only considered done to guard it from robbers and does not carry with it [the] trapping [prohibition].
Summary May one lock the closed door of a room that contains an animal?
Yes even if he is doing so for further security.
10. Using one’s body to block the exit of a room that contains an animal:
A deer which entered a home and a person [came and] sat by the entrance totally blocking it, which means that there does not remain enough space between himself and the doorpost for the deer to be able to escape through, then he is liable.
Having a second person sit next to the first: [However] it is allowed for another person to [come] sit by the side of this [person] in the unblocked area which is between [the first person] and the doorpost even though that by doing so he is adding further fortification to the fortification provided by the first person.
[Furthermore] even if the first person stood up and left and thus his fortification has been annulled, but the deer is still guarded due to the sitting of the second person, meaning that the now free space between himself and the doorpost, which was the area where the first person sat, is not enough space to allow the deer to escape, nevertheless the second person does not need to get up, and it is thus permitted for him to sit there until after Shabbos and then come take the deer.
The reason for this is: because since at the time that he sat down it was allowed for him to do so being that the deer had been already considered trapped through the sitting of the first person, [therefore] we do not require him to leave after the first person gets up, as he is doing nothing by his [continued] sitting, being that he is only guarding a deer which had already been trapped by the first person.
Sitting next to the first person with intention to trap the deer: [Furthermore] he may even sit near the first person with intent to remain sitting there after the first person leaves.
Summary-May one use one’s body to block the exit of a room which contains an animal?
No [even if he does not intend to do so in order to trap it, although if he did so unintentionally, then he does not have to move]
11. Covering a vessel that has flies or other flying insects in it:
One must be careful not to close a box or cover a vessel which has flies inside it, being that they are [consequently] trapped through this covering and closing.
The reason: Now, although one has no intent at all to trap [them], nevertheless [it is forbidden because] it is an inevitable consequence [of one’s action, in which the law is that it is forbidden to do even if one does not intend to do so].
Leaving it slightly open: Rather [if one nevertheless still wants to close it] he must place a knife or other item between the cover and the vessel in a way that the [flies] can escape from [inside the vessel] and it will no longer be inevitable [for them to leave].
Other Opinions: [However] there are opinions which are lenient [to allow one to completely close the vessel] in a situation that if one were to open the vessel to take [into ones hand] the flies that in there, then they would escape [before him being able to grab them], as in such a case there is no trapping done at all through this covering.
The Final Ruling-No need to check a vessel before closing it: One may rely on this latter opinion with regards to not being required to be meticulous and check if [the vessel] has flies [in it] [before covering it]. [Furthermore] even if one sees for certain that there are flies in it, it suffices for him to chase away those that he sees with his eyes and he does not have to check for any more flies that have perhaps remained. As since there is a doubt as to whether there are any [more flies] in there, it is no longer [considered an] inevitable [consequence of one’s actions that he will trap the flies].
Summary-May one cover a vessel if there are insects, such as flies inside it?
No. He must either a) rid it of all the flies and other insects that are currently visible to him, although he does not need to search it for any more insects. Or b) leave it slightly open to the point that the bugs can fly out.
Must one search a vessel for bugs prior to closing it? No.
12. Covering a beehive in order to protect it from damage:
Leaving an escape route available: It is allowed to spread mats over a beehive on a sunny [day] in order [to protect it from] the sun and [on a ] rainy [day] in order [to protect it from] the rain, as long as one has no intent to trap the bees. As well it must be done in a way that does not inevitably trap them there, such as for example he leaves a hole in the beehive that is not covered by the mats and it is [thus] possible for them to escape through there. Even if the hole is small and on the side in which it [thus] is not visible to the bees, [nevertheless] this does not pose a problem, being that he does not intent to trap [them], and it is not inevitable [for them to escape], as it is [still] possible for them to escape through this small side hole and it is not definitive that they will not escape through it.
However if there is no hole that is [left] uncovered by the mat, then it is forbidden because it is impossible [for them to escape].
The reason: Now, although there are opinions which are lenient regarding [covering a vessel with] flies in a situation that if one were to open the vessel to take [the flies] that are there then they will escape, nevertheless here it [is not allowed because it] is considered a complete trapping for the bees to be trapped in their beehive in a way that that it is not possible for them to escape even though he is not able to take them out from there with his hands.
[The reason for why it is considered a complete trapping is] because the beehive is their [common] place of trapping [in a scenario] that they reside in a beehive, and is [thus] similar to one who traps a lion and enters it into its cage that even though he is not able to take it from there with his hands without having it escape he is [nevertheless] liable because that is its place of trapping.
Summary-May one cover a beehive with a cloth in order to protect it from rain and the like?
Only if he leaves at least one hole uncovered through which it is possible for them to escape through.
However when done in order to trap the bees it is forbidden even with a hole left uncovered.
13. Trapping pets and farm animals:
A. The Biblical Prohibition-Trapping rebellious pets and farm animals:
Animals and birds which are raised in a person’s property, such as one who breeds deer in his house or in his courtyard or geese and chickens and doves, then if one trapped them on Shabbos he is exempt [from liability] being that they are already [considered] trapped.
However all the above only apply if they have not rebelled, however if they have rebelled, [including] even a cow that rebelled, and it goes without saying [that it includes] wild natured animals and birds that have rebelled, then one who traps them on Shabbos is liable just like having trapped wild [non-domestic] animals and birds as these [animals and birds which have rebelled will] too, do not enter into their cage at night.
Wild pigeons which nest in ones property: One who traps [wild] pigeons which reside on nests and high surfaces is liable because they are lacking further trapping as when a person comes to take them from their nest they are trained to escape and run away from their nest.
Birds which are raised in a house and when they enter into their coop in the evening are easy to be caught, being that they are not able to escape [ones grasp] and run away from there, then even when they are outside their coop they are not considered lacking further trapping being that at night they will go into their coop on their own. However nevertheless it is Rabbinically forbidden to trap them, which means to run after them until they enter into an area in which they are easily caught there. However to move them with ones hand is forbidden regardless of the trapping prohibition because of [the fact that they are] Muktzah.
However this is only referring to when [these birds] are in the courtyard or in a house so large that if they had not been raised around humans then they would need to be trapped, meaning that one would need to seek schemes to catch them there and they are thus considered lacking further trapping. For example if the house is so large that one is not able to catch them with a single chase and [rather must] runs after them until they enter into a room which is not very large and he then closes the door in front of them [then it is considered that the bird was lacking further trapping].
Helping a chicken enter back into its coop: However it is permitted to push the chicken from its back with ones hands in order so it enter [back] into its coop if it ran away from it.
C. Trapping pet birds [or wild natured animals] from an already trapped area:
However if they are in a house which is not very large then they are [considered] already trapped and waiting [and is thus not at all prohibited to be further trapped].
D. Trapping pet birds or wild natured animals from one large area to another large area: 
[As well] even if they are in a large house or even if they are in a public domain and one pushed them until they entered into another large house, then there is no trapping [prohibition involved here] at all and it is thus permitted [to even initially be done].
E. Trapping calm natured pets and farm animals:
All the above [Rabbinical prohibition to further trap a domestic creature only] refers to wild natured animals, and [all] birds; however calm natured animals which are raised in a person’s property are permitted to be trapped even from a public domain.
F. Trapping pet Cats: 
A cat has the same law as any other wild natured animal and is forbidden to be trapped in ways other than those explained [above in C and D].
It is only Biblically forbidden to trap pets and raised animals if they have rebelled against their master and will not enter on their own into their sleeping quarters at night.
It is Rabbinically forbidden to further trap all home raised birds and wild natured animals that are trapped in a large room in which they could not be caught with a single chase.
It is permitted to trap a pet or house raised animal in the following conditions:
- The animal has not rebelled against its ownerAnd
- It is a calm natured animal such as a cowOr
- All pets may be brought from one large area to another large area and from an area where they can be grasped with a single chase into a smaller area
If one tamed a wild animal to follow his every order, can he further trap that animal on Shabbos?
Perhaps in such a case it is similar to domestic livestock and does not contain a trapping prohibition. However perhaps it is still different as in the end of the day the animal is wild and runs around as if it is not trapped.
Is commanding a pet to go to its cage considered trapping it?
If a parakeet lands on ones arm may one bring it to the cage and have it walk in?
May one push a chicken back into its coop?
No. Although one may push it until it reaches its coop and then let it enter on its own.
May one trap a pet scorpion which escaped its cage?
Had its stinger removed: No, unless its bite can cause bodily damage.
Did not have its stinger removed: May be trapped and casually killed.
14. Trapping to prevent injury
A. Initially trapping creeping creatures which can cause bodily injury [in contrast to mere pain]:
Even initially it is allowed to trap all types of creeping creatures which commonly cause injury, such as snakes and scorpions and the like, even in places where their bite [or sting] is not deadly, and even if they are not currently chasing after him at all, and rather he just suspects that perhaps it may eventually chase after him or after someone else and bite [or sting] him or that perhaps he may not [properly] avoid [stepping on or near] them and they will bite him or perhaps will bite other people which do not know that they have to beware from them. As since one is only trapping them in order to save himself from injury, this is [considered] an action that is not done for its own self use.
The reason: Now, although that any [forbidden] action which is not done for self use despite not being liable on, is Rabbinically forbidden, [nevertheless] here the Sages completely permitted it due to chance that one may receive bodily injury [if he were to not be allowed to trap them]
[Furthermore] even according to the opinions which say that an action done not for its own self use one is [also] liable on and [thus according to them it should be prohibited being that] we do not [allow one to] transgress Shabbos through doing a complete Biblical prohibition [just in order to prevent] bodily damage and rather is only allowed to prevent danger of one’s life, nevertheless here since one is not trapping them in the normal method but rather just deals with them in order so they not be able to injure, [such as he] covers them with a vessel or surrounds them [with items that prevents them from escaping] or ties them so they not cause damage, therefore the [Sages] permitted one to do so even to creeping creatures which are not at all deadly and rather only cause injury.
Charming snakes and scorpions to prevent injury: One may charm snakes and scorpions on Shabbos so they do not cause injury even if they are not pursuing oneself, and doing so does not contain the trapping prohibition even according to those opinions which hold liable one who does an action that is not needed for itself.
B. Trapping insects and the like which only cause pain:
[However] all the above is referring to [trapping] creeping creatures which commonly cause injury such as snakes and scorpions, [which may be trapped] even in places that their bite is not deadly being that nevertheless they cause bodily injury with their bite, and the same applies for all creatures of the like. However anything which does not damage the body but rather just causes it pain alone, such as wasps, and flies, mosquitoes and fleas and the like, then it is forbidden to trap them.
Removing a stinging insect from ones cloths or skin-First Opinion: It is therefore forbidden to take hold of a flea which is on ones clothes, even if it is inside [ones clothes] close to his skin, and even if it is on his skin and has still not stung him it is forbidden to grab it.
Other Opinions: There are opinions which permit to grab the flea even while it is on the inside of his clothes [and not yet on his skin] being that it is able to cause him pain there. [Furthermore] even from his undershirt on the outside it is allowed to grab it since an undershirt is close to the flesh and it is thus possible that the flea will go from there to his flesh and will bite him. [Regarding the reason that this is allowed-see C and the reason mentioned there!]
However [even according to this opinion] if the flea is on the person in a way that there is no worry that it may bite him, [such as] that it is on his upper clothes on the outside, then it is forbidden to grab it.
Shaking ones cloths to caused the insect to fall off: Nevertheless it is [always] permitted to make it fall off of him through shaking [his cloths].
The Final Ruling: The final ruling is that if it is possible for him to easily make it fall off of him without [needing to] take it with his hand, then one is to do so even if [the insect] is on the inside of his undershirt. However if one is wearing long boots which reach to his thighs [or pants] and it is thus difficult for him to shake it away without first grabbing it with his hand then one who relies on the lenient opinion regarding this Rabbinical prohibition has done no harm.
The prohibition to kill or squish an insect which is in the midst of stinging oneself: The above allowance is only with regards to lifting the insect off oneself, however to kill it is forbidden according to all opinions even if it’s on ones flesh and is in the midst of biting him. …….[Furthermore] even to squeeze it with ones fingers to weaken its strength so that it not return to him is forbidden because of a decree that one may come to kill it. Rather he is to take it in his hand and throw it away. [See Chapter 2 Halacha 7 for the reason behind this prohibition]
C. Removing an insect that is in the midst of stinging
If a flea is in the midst of stinging oneself then it is permitted to take hold of it while it is stinging and to throw it away.
The reason for why this does not involve the trapping prohibition is: because when one takes hold of it at the time of the stinging he has no intent to trap it and rather is only involving himself with it in order to stop it from stinging him, and [when there is no intent to trap] the [Sages] did not decree [against trapping] even in a case [that doing so is only to prevent] pain alone since [these insects] are items which their species are not commonly trapped [and thus even when trapped with intent it is only Rabbinically forbidden].
The reason this does not involve the Muktzah prohibition: As well, the [Sages] did not decree in a scenario [that involves] pain the prohibition in moving the flee due to it being Muktzah.
Grabbing a wasp in the midst of stinging: Similarly if a wasp and the like stings him one is allowed to take it with his hands and send it away if it is not possible to fly it away.
The prohibition to kill or squish an insect which is in the midst of stinging oneself: It is only permitted to trap a flea which is in the midst of biting oneself, however to kill it is forbidden according to all opinions even if it’s on ones flesh and is in the midst of biting him………… [Furthermore] even to squeeze it with ones fingers to weaken its strength so that it not return to him is forbidden because of a decree that one may come to kill it. Rather he is to take it in his hand and throw it away. [See Chapter 2 Halacha 7 for the reason behind this prohibition].
The Sages allowed one to trap creatures which pose a threat in the following scenarios:
- Causes bodily injury:It is permitted to trap for sake of protection all creatures which can cause bodily injury [as opposed to mere pain] even if they are not chasing after oneself. It is forbidden to trap them for other purposes.
- Only causes pain but is on one’s inner clothing or skin: It is forbidden to trap even for protection in a case that they do not cause bodily injury even if they cause pain. However, if a [non-deadly or bodily injuring] insect is in ones inner clothing [the one that touches his skin] or on ones actual skin but not yet in midst of a bite then if it is difficult to brush the insect away one may be lenient to pick it up with his fingers and throw it away. However there are opinions which are stringent.
- Insect is in the midst of a bite or sting: If the insect is in the midst of a sting or bite then if it cannot easily be brushed off, according to all opinions one may grab it with his hands and throw it.
Being careful to not kill the insect upon lifting it: However when doing so it is forbidden to even squeeze the insect in the process as he may come to kill it which is forbidden in all cases, even if the insect is in the midst of a sting.
If insect is on outer clothing: If the insect is on his outer clothing then one may not pick it up and must rather suffice with brushing or shaking it away.
One may trap in order to prevent danger:
One may not trap [unless condition 2/3 is fulfilled]:
May a wasp be trapped when in the presence of an infant?
Some Poskim rule that they may even be killed when near an infant, as their sting can be lethal. However seemingly this no longer applies today, and they thus may not be trapped.
May one trap an insect which he is allergic to?
If one knows that he is allergic to a certain insect sting, and he could get from it a lethal allergic reaction [not just mere pain] then one may trap it and even kill it on Shabbos.
May one trap a hornet which is disturbing ones Shabbos meal?
Allergies: If there are any people which are allergic to their sting then it may be trapped or killed.
No allergies: Then it may not be trapped.
May one trap a snake if he is unsure if it is poisonous?
This requires further analysis.
May one trap a wasp or bee if he is unsure if he is allergic?
Seemingly one may not do so as is implied from the ruling regarding spiders in 316/23 that there being a chance that an insect is deadly is not a good enough reason to allow killing it.
It is only permitted to trap on Shabbos in the following cases:
- A calm natured pet or farm animal which has not rebelled
- A wild natured pet which has not rebelled may be brought from one large area to another large area and from an area where they can be grasped with a single chase into a smaller area
- Trapping creatures to prevent bodily injury to oneself [as opposed to mere pain].
- Grasping gently an insect in the midst of a bite or sting, or that is on one’s skin and one cannot remove it in any other way.
 A type of animal with a unique colored skin
 A type of fish which makes blue dye.
 As for the reason that trapping a ram is not mentioned, despite it being mentioned in 316/13 regarding the principal Melacha of Shechita, perhaps the reason is because they were considered domestic animals which were raised by many Jews at that time, and there was thus no need to trap them.
 See Halacha 4
 The sparrow is the smallest species of birds. They live on branches of trees and spend their time singing. Due to their small size they can live in a house just like in the outside and fly from corner to corner being very difficult to catch. [Mishneh Berurah 1 and Biur Halacha] This translation is based on the modern day Hebrew term used for this bird and is founded also on the words of the Peri Megadim, brought in the Biur Halacha above.
 There it discusses when a fish is considered to be trapped.
 See C!
 It is evident from Halacha 16 that this includes even species which are commonly trapped only because they are harmful, however on such creatures one is only liable for trapping them if he intends on doing so in order to use them, such as for healing and the like.
 Meaning that they have not been domestically raised. [Rashi Beitza 24a, and chapter 497 Halacha 16]
 316/ 3
 316/ 7
 316/ 1
 316/ 2
 The Mishneh Berura [316/55] rules like the 1st opinion that there is no trapping prohibition involved.
 Which means that it is common for the [people of the] world to trap this species that he is trapping. [Ibid]
 121 note 1
 Biur Halacha
 SS”K chapter 27 note 145
 This can hold true even according to the stringent opinion in Admur mentioned above that it is Rabinically forbidden to trap even an animal that lacks any trapping, as a)They were referring to an animal that in general needs trapping in contrast to here, and b) Perhaps that Rabbinical prohibition only applies by animals that are commonly trapped as opposed to here.
 So is evident from 339/3 in which no trapping prohibition is mentioned for the reason in why it is forbidden to jail a person on Shabbos, and so is evident from Poskim mentioned below. Avnei Nezer 189/22 writes there is no trapping prohibition by an adult however regarding a child he leaves this matter in question.
 Tzitz Eliezer brought in Piskeiy Teshuvos 316
 Kaf Hachayim 316/27
 Avnei Nezer ibid
 And accordingly it would remain forbidden to lock a child in his room. However Tzitz Eliezer writes that a child is in fear of his parents and is thus in any event already considered like trapped and there is thus no problem in locking him there.
 Rav SZ”A in Yesodei Yeshurun, brought in Piskeiy Teshuvos 316/3
 339/3; In Yesodei Yeshurun, in name of Rav SZ”A they mention that arresting a person never involves the trapping prohibition as they do not run away from society to be considered a trapping needed creature.
 M”B 339/14; Kaf Hachayim 316/27
 Aruch Hashulchan 339/11; Tzitz Eliezer 11/23
 To note that mice are not something which are trapped for their bodies use and may not be commonly trapped, and are thus not included in the Biblical prohibition of trapping even if it gets trapped in the process of setting up the trap.
 Halacha 6
 However the Rambam Shabbos 10/22 rules it is Biblically forbidden and so is implied from Rama 316/2
 However the Peri Megadim explains that this only applies when hunting for a hobby. However one whose occupation involves hunting may use hunting dogs to do so.
 Lit. see
 Halacha 3
 Peri Megadim 316
 Halacha 12
 Halacha 9
 Halacha 10-11
 Meaning that they have not been domestically raised. [Rashi Beitza 24a, and chapter 497 Halacha 16]
 From 316/25 it is evident that the following Halacha includes wild animals as well.
 חיות refer to wild animals such as the hart, dear, gazelle and yachmor.
 בהמות refers to domestic animals such as sheep, cows, and goat.
 See M”B 316/57 regarding a very tamed chicken that never runs away that it does not have the trapping prohibition.
 So is implied from 308/79 that when it enters into the trapped area on its own accord then it is not considered trapping.
 308/79 regarding pushing a chicken until it goes [on its own] into its coop.
 The Taz 
 Based on Taz 8 that he explains there that the “Chaluk” is the shirt closest to the skin while a regular shirt is called something else.
 Based on Mishneh Berurah 128/16 and the Alter Rebbe there in 128/6
 Tzaruch Iyun why wearing long boots should consider it difficult. Perhaps then this is referring to only when the flee has gone inside his pants or boot, in which case it is difficult to shake it off of him entirely.
 Lit. has not lost
 Meaning in addition to there not being a decree when there is bodily injury, but even for mere pain there is no decree in such a situation.
 316/18 and 19
In SSH”K 25 footnote 7 they write that based on the Mishneh Berura 46 which differentiates between lots of pain and a small amount of pain, there may be room for one to be allowed to trap a wasp if its sting gives him tremendous pain. However clearly according to Admur one may not be lenient.
 SSH”K 25/1
 Advice: Try using the end of a broom to latch it on the broom and then take it outside.