What Makes It Kosher
As stated above, all the kosher laws were either commanded by G-d at Sinai and incorporated in the Torah along with the other mitzvoth; are oral traditions which go back to Moses, who received them from G-d; or were ordained by the sages for the purpose of safeguarding and strengthening their observance and with health considerations in mind. Kosher (כשר) means, “That which is fit to eat according to biblical dietary law”. Now, though the kosher dietary law is comprised of many diverse subjects, nonetheless, since they chiefly revolve around the consumption of meat, we will, therefore, begin by explaining the requirements of kosher meat. Before meat may be consumed several prerequisites must be fulfilled:
Kosher and Non-Kosher Animals
Only the meat of certain animals may be consumed. The Torah specifies the signs by which to recognize kosher animals. They all are herbivores which chew their cud (That is, they must be ruminators) and have completely split hooves. Of the domesticated animals, this includes cows, sheep and goats. Kosher undomesticated animals include the addax, antelope, bison, buffalo, deer, gazelle, ibex, and reindeer, as well as others too numerous to enumerate here. (You are not likely to find them in your local neighborhood grocery store.) The Torah also lists four animals that only have one of these characteristics, but not the other. They include the pig, which has split hooves but does not chew its cud, and the camel, hare and rock-badger, which chew but do not have split hooves. These animals are not kosher.
It is interesting to note that though much of the world; such as Australia, North America, South America, Antarctica and great portions of Africa, Asia and Europe, were as yet, undiscovered when the Torah was written, the Torah, nonetheless, emphatically states that these four species possess only one kosher characteristic and not the other. The Talmud concludes that since only these species were named, no other such species exist. Incredibly, though tens of thousands of previously unknown creatures have since been discovered, categorized and studied, not a single additional one fits this description. This, itself, is ample proof of the Divine authorship of the Torah. Only the Creator Himself could know with certainty that no other such animals exist.
Indeed, the Malbim writes that had a human being, such as Moses, authored the Torah himself; he would never have risked destroying his credibility by listing these four animals. He could simply have stated that only animals that possess both these signs are kosher and left it at that. That would have been sufficient information for us to recognize the kosher animals and to reject the non-kosher ones, including those which possess only one of the two signs.