Jewish Values Online - (Aside from the obvious answer that the Torah says not to) why can't we mix different breeds of animals? [Administrator note: Presumably this is being asked both in regard to working them, as the Torah states for oxen and donkeys, and in breeding them - mixed kinds, as in 'designer' dog breeds.]

Many rules in the Torah do not include an explanation; therefore, any response is, by definition, speculative. Nevertheless, our tradition contains many such speculations, including with regard to this question.

The Torah contains many rules about not “mixing kinds.” This has been applied to breeding animals of different species, planting different kinds of crops in the same part of the field, grafting branches of one kind of tree onto another (all these are called kilayim, from the old Semitic rout k-l-a, meaning “double” or “two”). The law even applies to wearing clothing made from wool (animal product) and linen (plant product), the mix is called shatnez (meaning of word unknown).

Some have associated these prohibitions with the image of "God as the Creator"—the argument being that God is the creator and humanity should try and keep the world in essentially the same set up that they found it. This stands out in the first chapter of Genesis, which describes God as creating by “separating” one thing from another: light from dark, land from water, etc. This is even how the creation of the Israelite people is described, including in the blessing of the Havdala (God separated Israel from the other nations.)

The matter of working two different types of animals together is somewhat different. In that case, it has been argued that it is difficult for the weaker or slower animal to keep up. The law is probably related to the general concern of not causing unnecessary pain to animals.

Zev Farber

Answered by: Rabbi Zev Farber

While the pre-eminent medieval commentator RaShI was of the opinion that the statutes against the breeding of diverse kinds of cattle or planting diverse seeds within the same tract of land, or even yoking together different breeds of animals were without reason, Nahmanides disagreed. The latter asserts (Leviticus 19:19) that there are indeed reasons for these statutes but the reasons are hard to grasp. Accordingly, Nahmanides explains that the prohibition against “mixed species” is based on the notion that the order of the universe must be preserved. God designed a world in which only animals of the same species can mate with the resultant offspring able to reproduce in turn. Breeding species of diverse kind only violates natural law. It also constitutes a rejection of God’s intentions. Working an ox and an ass together, Nahmanides goes on to say, may very well result I stabling them together where they come to mate one with the other. Rabbi Samson Raphael Hirsch, in his book Horeb, similarly associates the laws against “mixed species” as a guarantee of retaining the order of nature. He goes so far as to say that the Hebrew word for mixed species, kilayim, comes from the root meaning “to close up.” It is God’s design to keep the integrity of each species intact and to violate this notion is to make a mockery of God’s creation.

Answered by: Rabbi Wayne Allen

As we study and learn about Torah and our tradition many questions arise. This particular question, regarding the mixing of different breeds of animals, has been asked many times over the generations.

The Hebrew word kilayim means “of two kinds,” and is the term written in the Torah that is the source of the answer to your question. Anything “of two kinds” (mixing animals, seed or cloth) is forbidden. According to the rabbis the law forbidding the mixing of animals (or any other matter), found in Leviticus 19:19, falls into the category of chukim - a commandment whose purpose and meaning are not obvious or rational to us, but we must observe the commandment. (The 613 commandments are all commandments but can be classified into different categories.) One of the sages, Nachmanides, clearly states that the mixing of breeds is prohibited because no new species may be created; all species were fixed at the time of Creation. His view is supported by other commentators, including Rashi.

It should be noted that this particular prohibition in the Torah is found within the section known as the Holiness Code, Leviticus 17-26. The Holiness Code covers a lot of ground and includes laws for proper worship of God, sexual behavior, priestly responsibilities, festivals and holy days, and ownership of land. Overall these commandments teach us to aspire to holiness. As Rabbi Louis Finkelstein so beautifully states, “Judaism is a way of life that endeavors to transform virtually every human action into a means of communion with God.”

Thus, Jewish laws and rituals are a way to think about, and engage in, living holy lives, even if the approach or methodology does not always seem logical to us.

Answered by: Rabbi Geri Newburge