The sugya examined here (Bava Kama 20a–21a) is appended to the mishnah (Bava Kama 2:2), wherein the ruling is given that the owner of an animal which eats food lying in the public domain is not obliged to compensate the owner of the food for his loss. This is because the type of damage done by the animal through eating is known as shen (‘tooth’), and the owner of the animal is only liable to pay for this type of damage when done in a private field, not when done in the public domain (based on Exodus 22:4, ‘and it feed in another man's field’). Nevertheless, the mishnah rules, even though the owner of the animal is not obliged to pay the full value of the food consumed by the animal, he is obliged to pay for the benefit he has received in that he has been spared the cost of feeding the animal. Say, for instance, the food eaten is costly and worth five zuzim whereas the cost of the animal's meal is only half a zuz, the owner of the animal certainly is not liable to pay five zuzim, since there is no payment for shen in a public domain, but he is obliged to pay half a zuz since he has benefited to this amount.