How do we know which animals are kosher?
According to the Mishnah (59a), although the Torah offers indicators for animals – split hooves and chewing its cud – it does not do so for birds. Nevertheless, the Sages established a number of indicators for birds:
· A bird that is a dores – it hunts its prey – is not a kosher bird
· A bird that has an extra toe, a crop, and a gizzard that can be peeled is a kosher bird.
The Gemara on today’s daf (=page) offers the source for these rules. The baraita teaches that the nesher is mentioned as one of the non-kosher birds and we know that a tor is a kosher bird since it is brought as a sacrifice. We can therefore conclude that:
Just as the nesher is unique in that it has neither an extra toe nor a crop, its gizzard cannot be peeled, it seizes prey and eats it, and is unclean, so all that have similar characteristics are unclean.
Torim have an extra toe and a crop, their gizzard can be peeled, they do not seize prey and eat it; just as they are clean, so all that have similar characteristics are clean
Traditionally, the nesher has been identified as an eagle, a bird of prey that is called an ayit in modern Hebrew. Rabbenu Tam argues that this identification cannot be correct, since eagles do have an extra toe. The Ramban adds that according to a passage in Sefer Mikhah (1:16) it appears that the nesher is bald, which would preclude identifying it as an eagle. An alternative identification is the gyps fulvus or griffon vulture, a bird of prey that has a very white bald head, very broad wings and short tail feathers.
In contrast to the nesher, the baraita points to the tor as the archetype kosher bird. In fact, the Torah does not list any kosher birds; the entire list of 24 birds mentioned in the Torah (see Vayikra 11:13-19) are non-kosher. According to the Torah (Sefer Vayikra 1:14), the two types of birds that can be brought as sacrifices are torim and benei yonah – turtledoves and pigeons. The tor that is referred to is identified as Streptopelia turtur, while the yonah is identified asColumba livia domestica. Since they are brought as sacrifices, the Gemara assumes that they must be kosher for mundane purposes, as well.