The fourteenth perek of Massekhet Shabbat deals with two subjects that are only minimally related to each other. It begins with a continuation of the discussion of the laws of trapping, which began in the previous chapter. Slaughtering is enumerated in the list of thirty-nine categories of primary labor after trapping. This primary category of slaughtering includes two major subcategories, wounding and killing. In order to advance the discussion and to specify the animals for which the prohibition to take a life applies, it is necessary to determine what is considered a living creature.
Clarification of the primary labor of wounding is even more complex. The term wounding as it is used in the Torah denotes shedding blood, whether by causing blood to flow out of the organism or by causing blood contained in the blood vessels to be displaced and accumulate underneath the skin, as in the case of a bruise. This definition necessitates the making of various distinctions pertaining to the laws of wounding on Shabbat. For example, is the skin of all living organisms considered skin in this regard, in which case one who causes any animal an internal wound is liable? Or perhaps there are creatures whose skin is not considered skin for these purposes.
The Mishna teaches:
With regard to any of the eight creeping animals mentioned in the Torah, one who traps them or wounds them on Shabbat is liable.
The Torah states: “The following shall be impure for you among the creeping animals that swarm upon the earth: The weasel, and the mouse, and the dab lizard of every variety; and the gecko, and the land-crocodile, and the lizard, and the skink, and the chameleon” (Vayikra 11:29-30). In truth, there is no clear oral tradition with regard to the identity of the eight creeping animals listed in the Torah. Therefore, determining their identity involves educated conjecture. Even commonly accepted identifications, such as the dab lizard [tzav] and the mouse [akhbar], are subject to debate. In addition, the Talmud’s description of the skins of these animals is insufficient to provide definitive identifications.