Leviticus 11:3

Whatsoever divideth the hoof and is cloven-footed, and that which hath horns bringing up the cud among the beasts, that you may eat.

hoofed an adjective, as in “horned and hoofed” [Psalms 69:32], denoting anything that can be said to have a hoof.

split an adjective, denoting an animal whose hoofs are split.

cud-chewing “cud” [Hebrew: gera] is derived from the word “throat” [Hebrew: garon. chewing a verb. Scripture mentions the camel, the cony, the hare, and the swine, because each of these species displays exactly one of the signs. The Hebrew language generally uses the name of the male of the species as a generic term which includes the female as well. Here Scripture uses the term for a female cony — some say because the male is rarely seen, some say because the male becomes female and back again. The former explanation seems more probable.

WHATSOEVER PARTETH THE HOOF, AND IS WHOLLY CLOVEN-FOOTED, AND CHEWETH THE CUD, AMONG THE BEASTS; THAT MAY YE EAT. The meaning of this verse is that every animal which has these two signs, you may eat, but you may not eat it if it has only one sign. Now it would have been proper if He would merely state the law in this general way. However, He singled out the camel, the rock-badger, and the hare as having only the one sign of chewing the cud, and the swine as having the one sign of a parted hoof, because there are no other animals in the world that have only one sign. He then repeated [as a general rule applying to those with no sign at all, and those with only one sign], Of their flesh ye shall not eat, which denotes a negative commandment.
Now Rashi wrote: “From this verse I know only about these [four animals mentioned]. Whence do I know that other unclean animals that have no signs of purity, may not be eaten? You derive it by the rule of kal vachomer., p. 133, Note 208, for further explanation. How is it with these four animals mentioned, that have some of the signs of purity? They are forbidden! [It follows all the more so that those which have none of the signs, are surely forbidden to be eaten!]” In the words of the Sifra: 3:2. “What is the law concerning those animals that have some of the signs of purity? They are forbidden to be eaten by a negative commandment. Is it not logical that other unclean animals which have none of the characteristics of purity, should be forbidden to be eaten by means of a negative commandment! Thus we find that the camel, the rock-badger, the hare and the swine are explicitly forbidden by Scripture, whilst the other impure animals are forbidden on the strnegth of a kal vachomer., p. 133, Note 208, for further explanation. It is also established that the positive commandment [regarding unclean animals] is Scriptural, (Verse 2). From this we deduce the converse, negative commandment, that any animal which does not have these two characteristics of a permissible animal, is not allowed as food; and a negative commandment derived from a positive commandment has the force of a positive commandment. Hence one who eats an impure animal violates both a positive commandment [these ye may eat, as explained above], and negative commandment [of their flesh ye shall not eat], See “The Commandments,” Vol. II, pp. 167-168). while the negative commandment regarding them is …

מפרסת פרסה, a nail similar to a shoe; the word, though it sounds like it does not mean “two or more separate nails,” such as are found on the toes of rabbits, etc.

ושסעת שסע, the hoof being completely split into two parts, unlike the hoof of a horse or donkey which is all in one piece. According to the plain meaning of the text and the opinion of the heretics all the domesticated beasts, free roaming beasts, birds and fish and certain types of locusts and other creeping creatures that G’d has outlawed for consumption by Jews is due to the fact that they cause excessive heat in our bodies when eaten, affecting our health detrimentally, and therefore they are called טמאים, impure. There is support for this theory also among physicians. Even in the Talmud (Shabbat 86) the opinion is offered that gentiles who do consume these creeping creatures damage their bodies thereby.

מעלה גרה; regurgitating the food into the foodpipe before finally digesting it.