If one sees a rattlesnake on Shabbos what should he do?

This question involves pikuach nefesh – saving lives and must therefore be taken in the correct perspective. Although Shabbos is one of the fundamentals of our religion nevertheless preserving Jewish life was placed by the Torah on an even higher level.

Common sense has it that when being pursued by a poisonous snake or scorpion one is permitted to exterminate them on Shabbos due to pikuach nefesh. The innovation of the halacha is that even if that particular animal is not pursuing anyone and even if it is scurrying away in the other direction, one is permitted to chase and exterminate it. [1]

It is obvious that Chazal were afraid that the animal might harm someone else and they permitted its extermination to prevent harm to human life.

This halacha applies to all dangerous species and hence one may kill a rabid dog even when it involves ‘transgressing’ biblical prohibitions. [2] This does not mean that one should personally get involved with actually killing the dog if he has no experience or know-how as to the way it is accomplished. In any event he is permitted and obliged to contact the authorities and notify them of the potential danger.

 What if there are other solutions present which would dispose of the snake etc without having to transgress any prohibitions?

It does not always pay to be too clever. For example, if possible to confine a poisonous snake in a sealed a room until after Shabbos – which appears to be a probable solution – and yet might still pose a threat. It would require one to stand guard to prevent anyone unknowingly open the door. Therefore the optimal plan of action is to dispose of the threat as quickly and efficiently as possible.

 What about a snake or scorpion whose bite causes pain and distress but is not deadly, is one permitted to trap or kill them?

 We must preface and say that if there is any doubt as to whether a certain animal, reptile or insect is poisonous it should be killed on sight and any unnecessary risks must be avoided.

If a harmful, non-poisonous animal is pursuing a person it may be killed. This is because killing an animal under such circumstances is only a melacha she’eina tsricha l’gufa [3] and in order to prevent pain and harm it is permitted. [4]

In the event that the harmful reptile is not chasing anyone one may not kill it in the normal fashion. He may though purposely step on it on condition that he does it in a way which outwardly looks like an unintentional manner. [5]

This is to prevent unlearned people from saying that he is desecrating the Shabbos for no reason. [6]

The Mishna Berura [7] is, by the way, opposed to killing spiders on Shabbos merely on the hearsay that they are dangerous. Of course this would not apply to poisonous spiders; he is only dispelling a common fallacy that all spiders are deadly.

 If one’s dog rebelled and will not return home, is one permitted to trap it on Shabbos and bring it home?

 If the dog has ‘rebelled’ to the point that it does not return home at night, its trapping involves a biblical transgression and is forbidden to be trapped. If it does return home at night but at the moment refuses to heed its owner, it is rabbinically forbidden to be trapped.

According to the Rama, one is forbidden to trap one’s pet in all circumstances unless fully domesticated - i.e. the animal is so familiar with its owner that it answers to his bidding at all times.

 What if a parrot flew out of its cage, may it be trapped?

 The problem here is compounded with muktze, because a dog can be cornered without handling but it is quite hard to do that with a parrot. It is a problem opening the cage door on Shabbos as well, because once the door is open the parrot is relatively free and upon shutting it one is basically trapping it again. [8] If the bird would return to its cage at night there is more room to permit shutting the cage but nevertheless any opening of a parrot or birdcage should be preceded with rabbinic guidance as to the correct procedure.