Trapping, the av melachah of tzod,1 is forbidden on Shabbat. While trapping most creatures is definitely rabbinically forbidden, the Biblical prohibition of tzod is only transgressed if certain conditions are met:

  1. The trapper must intend to benefit from the animal. The general rule with Biblical prohibitions on Shabbat is that they are only transgressed if one intends to benefit from the forbidden action itself, not just to offset something else. So one who traps an insect because it was annoying, for example, only transgresses a rabbinic prohibition.
  2. The creature must be of a species that is usually trapped by people because it has some sort of use. This would exclude most insects or rodents.2 Even if a person traps one of these insects for some purpose, he is still not liable.3
  3. The animal must be trapped in a small enough space that it would be easy for one to grab it from there.4 The Alter Rebbe5 follows the view of Rashi6 and Maimonides,7 who define this as a setup where one can simply run over to the animal and grab it without having to make multiple attempts. The Mishna Berura,8 based on Rabbeinu Chananel,9 gives a broader definition: as long as one wishing to grab the animal wouldn’t need to rest between attempts, the animal is considered fully trapped. Trapping an animal by caging it in a larger area is a rabbinic prohibition.

Trapping in the Mishkan

The tachash was a unique animal whose hide the Torah required for several parts of the Mishkan, after which it became extinct. The chilazon was a type of snail or other sea creature whose blood was used to make blue dye for the tapestries in the Mishkan. The trapping of these animals is the source for the melachah of tzod.10

Pets and Domesticated Animals

One is not Biblically liable for trapping pet animals or birds which would not run away from their owner if he or she tried to handle them. One is, however, rabbinically forbidden from chasing them into an enclosed area.11 Therefore, one should not chase a pet dog into its kennel on Shabbat. Fully domesticated animals, such as cows or horses, are permitted to be enclosed since they are not considered free even when they are not caged.12 In general, animals are not to be handled in the usual manner on Shabbat due to the prohibition of muktzeh. For guidelines on how to take care of a pet on Shabbat, see How does Shabbat observance affect pet owners?

Dangerous Animals

Animals or reptiles that can cause serious harm to a person may be trapped on Shabbat, even when they are not posing an immediate threat. Trapping these creatures is not considered a Biblical transgression since one does not wish to gain anything by trapping them. However, this alone would not suffice to allow trapping them, since rabbinically one may not do a melachah even if one has no intention to benefit from the action he is doing. In this case, the Sages lifted their restriction to protect people from harm.13 The Sages did not lift their restriction with regard to pests or flying insects which can bite but do not inflict serious injury, and they may not be trapped. However, the Tur says, that certain flying insects are never considered trapped because the trapper would never be able to keep them from flying away once the trap is removed. For example, trapping a fly in an upside down cup would be permitted. In practice, we do not follow this view and one must leave enough space for the animal or insect to escape, or it is determined to be a violation of tzod.14

Setting Traps on Shabbat

Setting a trap on Shabbat is only considered a rabbinic prohibition, because the person’s involvement is only in laying the trap; the actual trapping happens on its own.15 The same applies to one who sends out a hunting dog to ensnare an animal on his behalf.16