When renting an animal, how limiting is the rental with regard to use of the animal for purposes beyond the specific agreement?
We have already seen that kol ha-mishaneh yado al ha-taḥtonah – whichever participant in a business deal changes the terms of the agreement is the one who loses out (see daf 77), but what uses are considered significant changes of the agreement?
The Gemara on our daf quotes a baraita that teaches that if a donkey is rented for a man’s use, a woman cannot ride it, although if it is rented for a woman to ride, then any woman can ride – whether she is large or small; even if she is pregnant or nursing (i.e. she is carrying a small child in addition to herself). Rav Pappa explains the latter case to even include a nursing mother who is pregnant, that is to say, a woman who in addition to her own weight and the additional weight of the child in utero, is also carrying a small child.
Tosafot point out that the baraita does not feel a need to distinguish between large and small men – it appears clear that men come in all sizes, and that an agreement to carry a man would include any man. With regard to a woman, however, there may be an assumption made about the average size of a woman, so the baraita needs to emphasize that once the donkey is rented for a woman, it makes no difference whether she is large or small.
It is not clear why an animal that is hired for a man cannot be used by a woman. Explanations range from the possibility that women commonly weighed more than men at that time to the suggestion that it is more difficult to arrange women on the animal.