17- Kashrut of Animals

01. The Restrictions and Prohibitions on Eating Meat

As we learned above (chapter 14), eating meat is a complex matter in several respects. On the one hand, meat gives a person great physical and spiritual strength, and when eaten for the sake of Heaven, it has intrinsic value as part of perfecting the world. On the other hand, the desire to eat meat can draw a person into indulgence and cruelty. As a rule, the more nourishing, beneficial, and tempting a food is, the more mitzvot the Torah gives concerning it, so that we may be guided and directed toward the good. For this reason, the Torah includes more mitzvot and prohibitions concerning meat than concerning other foods.

These are the mitzvot connected to eating meat: 1) not to eat non-kosher domesticated and wild animals, such as a horse or lion; 2) not to eat non-kosher birds, such as an ostrich, eagle, or hawk; 3) not to eat non-kosher fish, such as catfish; 4) not to eat non-kosher locusts; 5) not to eat creeping, flying, or aquatic creatures, such as frogs, shrimp, and lobsters; 6) to perform sheḥita on domesticated animals, wild animals, and birds; 7) not to eat their blood; 8) to cover the blood of a wild animal or bird; 9) not to eat the forbidden fat (ḥelev) of domesticated animals; 10) not to eat neveila, an animal that died without sheḥita; 11) not to eat tereifa, an animal that underwent sheḥita but was then found to have a bodily defect that renders it forbidden; 12) not to eat a limb from a living animal; 13) not to eat the sciatic nerve; 14) not to cook meat with milk, not to eat such a cooked mixture, and not to derive benefit from it. Rambam, in his introduction to the Laws of Forbidden Foods, enumerates these mitzvot as twenty-one commandments.

Some mitzvot have reasons that are readily understandable, such as honoring one’s parents, giving tzedaka, and the prohibition of murder. Even had these mitzvot not been written in the Torah, it would have been proper for us to observe them by reason alone; these are called mishpatim, rational laws. Other mitzvot would not have occurred to us had the Torah not written them, such as the prohibition of sha’atnez and the prohibition of eating forbidden foods; these are called ḥukim, divine decrees. In one sense, observing ḥukim expresses faith and attachment to God more fully, for we observe them only because God commanded us to do so, not because of any human rationale. From this perspective, these mitzvot sanctify us more deeply. It is therefore proper to be careful not to reduce them to human explanations that could diminish their sacred, divine meaning. In this vein, the Sages said: “A person should not say, ‘I do not wish to eat pork’ because it is repulsive. Rather, he should say, ‘I do wish to eat it, but what can I do? My Father in Heaven has decreed this upon me’” (Sifra, Kedoshim §128; Rashi to Vayikra 20:26).

Without losing sight of the basic truth that we cannot grasp the ultimate reason for the Torah’s ḥukim, we may still reflect on the values and meanings that these mitzvot teach us.

The most important foundation, one closely connected to the very nature of these mitzvot as ḥukim, is the distinction they create between Israel and the nations. God created many animals in the world, and after permitting human beings to eat the meat of all of them, He distinguished us from all nations and sanctified us with His mitzvot: He permitted us to eat only the kosher species and prohibited the non-kosher species. As it says:

“You shall not follow the practices of the nation that I am driving out before you, for they did all these things, and I abhorred them. I said to you: You shall inherit their land, and I will give it to you to possess, a land flowing with milk and honey. I am the Lord your God, who has distinguished you from the peoples. You shall distinguish between the kosher animal and the non-kosher, and between the non-kosher bird and the kosher bird; you shall not make yourselves detestable through animal or bird or anything that creeps on the ground, which I have distinguished for you as non-kosher. You shall be holy to Me, for I, the Lord, am holy, and I have distinguished you from the peoples to be Mine” (Vayikra 20:23–26).

The Sifra, in the same passage cited above, comments: “Just as I am holy, so you shall be holy; just as I am separate, so you shall be separate…. If you are distinct from the nations, you are Mine; if not, you belong to Nebuchadnezzar, king of Babylon, and his companions,” that is, to the kings of the nations who subjugated Israel. Thus, quite apart from any explanation or meaning we may suggest, the laws of kashrut set Israel apart from the nations and help preserve its unique identity as God’s people and as those who bring His word to the world.

02. Kosher and Non-Kosher Species

The Torah divides animals into four categories: 1) domesticated and wild animals, that is, mammals; 2) fish; 3) birds; and 4) creeping creatures, including reptiles, aquatic creatures, flying insects, and the kosher locusts. In each of these categories there are kosher species and non-kosher species, as will be explained in this chapter.

For domesticated animals, wild animals, fish, and creeping creatures, the Torah provides identifying criteria that distinguish kosher species from non-kosher ones. For birds, it uses a different method: it lists the non-kosher species, thereby teaching that all others are kosher.

Several great Rishonim note a characteristic trait of kosher species: they eat grass and have a gentle temperament, whereas non-kosher species are predatory and aggressive. Since the food a person eats affects his soul, the Torah commanded us not to eat species inclined toward cruelty (Ramban, Rabbeinu Baḥya, and Abarbanel to Vayikra 11; Akeidat Yitzḥak, Shemini, Gate 60).

Some wrote that kosher species are healthy to eat, whereas non-kosher species are unhealthy (Guide for the Perplexed 3:48). Many objected to mentioning this reason, arguing that it is improper to diminish the Torah by turning it into a book of remedies. Moreover, we do not find that gentiles are physically less healthy than Jews. Rather, the mitzvot are meant to sanctify Israel and refine their souls; when a Jew eats forbidden foods, he defiles his soul. Therefore, the Torah calls the species that may not be eaten temei’im — impure (Akeidat Yitzḥak, Shemini, Gate 60; Abarbanel to Vayikra 11).

The Sages likewise taught: “Sin dulls a person’s heart, as it says: ‘Do not become impure through them, lest you become impure through them’ (Vayikra 11:43). Do not read venitmetem — ‘lest you become impure’ — but venitamtem — ‘lest you become dulled’” (Yoma 39a). All sins, and especially eating forbidden foods, dull the heart, making it unable to receive sacred spiritual matters. In this respect, forbidden foods are more severe than other prohibitions, for the forbidden food enters the body, becomes integrated into it, and damages it (Ramban, Rabbeinu Baḥya, Akeidat Yitzḥak, Abarbanel, and Malbim to Vayikra 11).

03. The Criteria for Determining the Kashrut of Animals

The Torah sets out two criteria for determining whether a domesticated animal or wild animal is kosher, as it says: “These are the animals that you may eat from among all the beasts upon the earth: every animal that has a split hoof, completely divided into two hooves, and that chews the cud — that you may eat” (Vayikra 11:2–3).

The first criterion is a completely split hoof. A hoof is the hard covering, like a thick nail or soft bone, that grows over the bottom of the animal’s foot and allows it to walk on the ground without injury. A “completely split hoof” means that the foot and hoof are divided into two parts.

The second criterion is that the animal chews its cud. Since kosher species feed on grass, which is difficult and slow to digest, they have a special digestive system with four stomachs: 1) the rumen; 2) the reticulum; 3) the omasum; and 4) the abomasum. At first, these animals tear off grass quickly and swallow it after only minimal chewing. The food descends to the rumen, where digestion begins, and from there moves to the reticulum, where it forms into rounded pellets. It then returns to the mouth for extended chewing — this is what it means to chew the cud. Afterward, it descends to the omasum and finally to the abomasum.

Four species have only one of the two criteria and therefore resemble kosher species, but because they lack the other, they are non-kosher: the camel, the hyrax, the hare, and the pig. As the Torah states: “But these you shall not eat from among those that chew the cud or have split hooves” (Vayikra 11:4). The camel, hyrax, and hare are described as chewing their cud but not having split hooves: “The camel, though it chews its cud, does not have a split hoof; it is non-kosher for you. The hyrax, though it chews its cud, does not have a split hoof; it is non-kosher for you. The hare, though it chews its cud, does not have a split hoof; it is non-kosher for you” (ibid. 4–6). Biologically, however, the hare and the hyrax do not ruminate in the usual sense. Rather, their mouths appear to be constantly chewing, like those of ruminants, and the hare also eats its own droppings, which makes it appear to chew its cud. For this reason, the Torah states that they are non-kosher because they do not have split hooves (R. David Tzvi Hoffmann to Vayikra 11:4–6). The pig, by contrast, has split hooves but does not chew its cud, and is therefore non-kosher, as it says: “The pig, though it has a split hoof, completely divided, does not chew its cud; it is non-kosher for you” (ibid. 7).

The Sages gave additional identifying features of kosher species. Kosher species do not have front teeth in the upper jaw. Another feature appears in the flesh beneath the tailbone, which has a lengthwise-and-crosswise pattern, though this feature is also found in the arod, a non-kosher animal (Ḥullin 59a). The Sages also taught that the milk of kosher species can curdle into cheese, whereas the milk of non-kosher species does not curdle (Avoda Zara 35a). Horns, too, are mentioned as an indication that an animal is kosher, though not all agree that this is a definitive marker (Nidda 51b; Ḥullin 59a–b; Tosafot, Ḥullin 59a, s.v. elu).

In general, the Torah’s criteria for kosher species are also the traits of non-predatory herbivores. Grass is difficult to digest because it contains a great deal of cellulose, so God gave these animals a sophisticated digestive system and the ability to chew their cud, allowing them to continue breaking down their food after it has first been swallowed. Instead of claws for seizing prey, they have split hooves, suited to running through hills and climbing over rocks: they can find grass, eat quickly, and then escape predators to a safe place where they can chew at ease. The absence of front teeth in the upper jaw likewise reflects that they are not predators; their teeth are made for chewing grass. Their horns, too, are for defense, not attack. Even without the physical advantages of predators, kosher species thrive. This teaches that one who works hard and is content with what he has can find a good livelihood without preying on others.

04. The Kosher Species and the Laws That Apply to Them

The Torah lists ten kosher species: ox, sheep, and goat among domesticated animals, and seven wild species named in the Torah as ayal, tzvi, yaḥmur, ako, dishon, te’o, and zemer (Devarim 14:4–5).

Although the same criteria determine the kosher status of domesticated animals and wild animals alike, there are halakhic differences between them. Only domesticated animals may be brought as offerings. Since their sacrificial fats were burned on the altar, one may not eat their ḥelev. A separate mitzva applies to wild animals and birds: after sheḥita, their blood must be covered with earth, as explained below (18:9–10).

The Sages said: “It is revealed and known before the One Who spoke and the world came into being that non-kosher wild animals are more numerous than kosher ones; therefore, the Torah listed the kosher species” (Ḥullin 63b). As with all species in nature, these ten kosher species include a number of different breeds.

Because these three species are domesticated, their identities have remained clear through tradition. The first is cattle: the male is a bull or ox, the female a cow, and the young are calves. Cattle include many breeds, among them Damascus cattle, Holstein, Hereford, and Brahman. The second is sheep: the male is a ram, the female a ewe, and the young are lambs. Sheep, too, include many breeds, such as fat-tailed sheep, Merino, and Awassi. The third is goats: the male is a buck or he-goat, the female a goat, and the young are kids. Goat breeds include Baladi and Alpine. Sheep and goats together are called tzon, flocks.

The identity of the seven wild species was forgotten over the long years of exile, and today only two are known with certainty by tradition: tzvi and ayal. Nevertheless, the Torah’s criteria for kosher status in animals are clear, and any wild animal that has those criteria may be eaten. This is the accepted ruling as well regarding the zebu (Kol Mevaser 1:9).

According to contemporary zoological classification, all kosher domesticated animals and wild animals belong to the class of mammals, the order of even-toed ungulates, and the suborder of ruminants. Still, a species should be certified as kosher only after God-fearing experts have carefully examined its kosher features. If the examination confirms that the species meets the kosher criteria, it is kosher.^[1]

05. Birds

Rather than giving criteria for identifying kosher birds, the Torah lists the non-kosher species, thereby teaching that all other birds are kosher. As it says:

“Every kosher bird you may eat. But these you shall not eat from among them: the eagle, the vulture, and the osprey; the kite, the falcon, and the buzzard according to its kind; every raven according to its kind; the ostrich, the night hawk, the sea gull, and the hawk according to its kind; the owl, the cormorant, and the barn owl; the pelican, the carrion vulture, and the cormorant; the stork, the heron according to its kind, the hoopoe, and the bat” (Devarim 14:11–18). Similar verses appear in Vayikra 11:13–19.

The Sages said (Ḥullin 63b): “It is revealed and known before the One Who spoke and the world came into being that kosher birds are more numerous than non-kosher birds; therefore, the Torah listed the non-kosher birds,” teaching that all the rest are kosher.

From the Torah’s list, the Sages derived that there are twenty-four types of non-kosher birds. One who can identify all of them by name and by their distinguishing features may treat all other birds as kosher. Over the course of exile, however, this tradition was lost. The Sages therefore provided several identifying features to distinguish kosher birds from non-kosher ones. A bird that is dores, meaning that it seizes and kills prey with its talons, is non-kosher. One indication that a bird is dores is that, when placed on a string, it spreads its toes two to each side.

When it is unclear whether a bird is dores, it may be treated as kosher only if it has all three kosher features: an extra toe, a crop, and a gizzard whose inner membrane can be peeled. If the bird is known not to be dores, then even one of these three features is enough to establish that it is kosher (Ḥullin 59a; Tur and Beit Yosef YD 82:2; Shakh 82:4).

In practice, however, the Rishonim write that these features are no longer relied upon. There were cases in which people used them to identify a bird as kosher, only to discover later that it was dores and therefore non-kosher (see Ḥullin 62b). Therefore, today we eat only birds with a clear tradition of being kosher (Rashi, Rosh, SA and Rema YD 82:2–3).

The kosher birds eaten most widely today are chicken, above all, followed by turkey. Some communities also eat domestic geese, domestic ducks, mute swans, pigeons — including domestic and giant pigeons — turtle doves, sparrows, and quail.

The commentators explain that birds belong to a more refined realm than animals, and therefore most bird species are kosher. Perhaps for that very reason, though, birds are also more distant from us, and the traditions concerning them were lost. In practice, then, only a relatively small number of birds — those for which a clear tradition of kashrut has been preserved — are certified as kosher.

06. Cases of Doubt

When one community has a clear tradition that a particular bird is kosher, other communities may rely on that tradition as well, provided the tradition is known to be reliable and the only reason it was preserved there is that this bird was found in that locale throughout the generations.

If, however, the communities that refrained from eating the bird had a reason to prohibit it, their custom remains binding. This may be because the bird’s features raised doubt; because they believed that the community that ate it had not transmitted the tradition carefully enough; or because the bird resembled non-kosher birds, raising concern that people who ate it might come to eat non-kosher birds as well. In such cases, those communities must continue their custom not to eat that bird (Shakh YD 82:11, based on Rosh and Rashba). Members of the community that did eat it may continue their custom, provided it was practiced with the approval of their rabbis.

Turkey raised a well-known halakhic question. Since we eat only birds with a tradition of kashrut going back to the time of the Mishna, how could turkey be permitted? It originated in the Americas, which became known to Europeans only in 1492, so no such ancient tradition could have existed. Although turkey has all the kosher features enumerated by the Sages, some rabbis therefore refrained from eating it because there was no tradition concerning it.

In practice, however, turkey was ruled kosher, and Jews customarily eat it (Knesset ha-Gedola, YD 82:27). Apparently, when rabbinic authorities first encountered turkey, they did not regard it as a new species requiring its own tradition, but simply as another breed of chicken. Had the question first come before other authorities, they might have inclined toward stringency and treated turkey as a separate species. But once it had been ruled permitted and the practice spread through many communities, turkey became permitted for all Jews.

Others explain that the requirement of a tradition applies only to an uncommon bird. In such cases, even if the bird has the kosher features, we are still concerned that it may sometimes attack prey with its talons, and that this behavior has not been observed because the bird is not commonly found among us. But when a bird is found among us by the thousands, and everyone knows that it is not dores, it may be eaten on the basis of the kosher features enumerated by the Sages (Arugat ha-Bosem 16; Meishiv Davar 2:22). This, they argue, is the reason for the accepted practice regarding turkey.

07. Fish

Any fish that has fins and scales is kosher, as it says:

“These you may eat from all that are in the water: anything in the water that has fins and scales, whether in the seas or in the rivers — those you may eat. But anything that does not have fins and scales, whether in the seas or in the rivers, among all the creeping creatures of the water and among all living beings in the water, they are detestable to you. They shall remain detestable to you; you shall not eat of their flesh, and their carcasses you shall detest” (Vayikra 11:9–11; see also Devarim 14:9–10).

Fins extend from the sides of the fish and help it swim. Scales grow over the fish’s skin, forming an additional protective layer. Each scale is attached to the skin at one end, while its other end lies against the skin without being attached. A fish is kosher even if it has only one fin and one scale (Ḥullin 59a; SA YD 83:1), provided it is certain that the scale was attached to this fish and did not come from another fish and stick to it (Shakh YD 83:1).

Although the Torah mentions both fins and scales, the Sages taught that any fish with scales also has fins. In practice, then, scales are the decisive criterion for determining whether a fish is kosher (Ḥullin 66b; SA YD 83:3).

A fish does not need to have visible scales at every stage of its life. Some fish grow scales only later; others have scales when young and shed them as they mature; and still others lose their scales when removed from the water. All of these fish are kosher, because any fish that has scales at some point is considered kosher (Ḥullin 66a; SA YD 83:1).

The scales must, however, be visible to the naked eye. If they are very thin or difficult to see because of the fish’s coloring, one may wrap the fish in a cloth and then inspect the cloth; if a scale is found there, the fish is kosher (Avoda Zara 39a; SA YD 83:2).

Finally, the scales must be true scales. True fish scales are attached to the skin, but loosely enough that they can be peeled off by hand or with a utensil while the skin underneath remains intact. If they must be cut away, and the skin is damaged in the process, they are not scales but part of the skin, and the fish is non-kosher (Rema YD 83:1). For this reason, many authorities prohibit swordfish, because the scale-like formations visible on it are part of its skin; see the Herḥavot.

Fish do not require sheḥita, and the prohibition against eating a limb from a living animal does not apply to them. It is therefore permissible to cut a piece from a live fish and eat it. One may not, however, bite directly into a live fish. Doing so is forbidden both because of bal teshaktzu, the prohibition against repulsive conduct (Rema YD 13:1), and because it is cruel (Da’at Kohen 12).

08. Locusts

The prohibition against eating flying creeping creatures applies to winged insects with three pairs of legs, such as wasps, bees, flies, crickets, praying mantises, and locusts. Locusts, however, are treated differently from the others. Since they have special jumping legs, the Torah permits certain kosher species among them, as it says: “Every flying creeping creature that walks on four is detestable to you. But these you may eat from among all the flying creeping creatures that walk on four: those that have jointed legs above their feet with which to jump upon the ground” (Vayikra 11:20–21).

The Torah identifies kosher locusts by two criteria: they have two pairs of ordinary legs, along with kera’ayim, a third pair of large, raised legs used for jumping. The Sages transmitted two further criteria based on tradition: the locust must have four wings, and its wings must cover most of its body (Ḥullin 59a). Even if these criteria are not yet visible in a young locust, the species is kosher and may be eaten if they will appear as it grows.^[2]

The Torah names four kosher locust species: “These of them you may eat: the arbeh according to its kind, the sol’am according to its kind, the ḥargol according to its kind, and the ḥagav according to its kind” (Vayikra 11:22). The Sages understood the phrase “according to its kind” to include an additional related species for each one: arbeh includes tziporet keramim; sol’am includes Yoḥana Yerushalmit; ḥargol includes artzuviya; and ḥagav includes razbanit (Ḥullin 65a; MT, Laws of Forbidden Foods 1:22).^[3]

Like fish, locusts do not require sheḥita, and the prohibition against eating a limb from a living creature does not apply to them. It is therefore permissible to cut a piece from a live locust and eat it. One may not, however, bite directly into a live locust, or even bring it to one’s mouth as if to bite it, because this is repulsive and violates bal teshaktzu (Shabbat 90b; Rema YD 13:1). It is also forbidden because it is cruel (Da’at Kohen 12).

Some authorities maintain that ḥagav is the general name for all kosher locust species. On this view, even a locust with the kosher criteria may not be eaten unless it is also known as ḥagav (Rivam, Rosh, Ramban, and Rashba, following R. Yose). Therefore, locusts are not eaten on the basis of their physical criteria alone; there must also be a tradition that the species is included under the name ḥagav (SA YD 85:1). Once there is a reliable tradition that a particular species is kosher, we may assume that it is included under the name ḥagav.

In recent generations, the tradition permitting locusts was preserved in Yemen and Morocco, where locusts were common. The species permitted by that tradition is arbeh, including its varieties — the locust that at times gathers in vast swarms and destroys all vegetation.^[4]