Regulations governing food among practically all ancient and living religions, but especially among the Jews. In the Jewish tradition, these laws are enumerated in the Old Testament (Leviticus 11; Deuteronomy 14). They may be classified on three levels: cattle or beasts, birds, and fish. Among the cattle and beasts, they must meet two conditions to be legally edible: 1. have a divided hoof that is entirely split or cloven; 2. must chew their cud. Pigs are excluded, therefore, because they do not chew. Among birds, the Bible forbids certain one by name and some are now impossible to identify. In general, birds of prey are prohibited. Believing Jews eat only traditionally "clean" birds, such as hen, goose, and turkey. As for fish, the general rule is that only those with fins and scales are edible; so that oysters, lobsters, crabs, and eels may not be eaten.