Powtórzonego Prawa 14:7 Halacha: Mishneh Torah, Forbidden Foods & Mishneh Torah, Negative Mitzvot

If a kosher animal gives birth or if an animal with two backs and two spines is found in it, it is forbidden for consumption. In the Torah this is called shesua (split): "Nevertheless these ye shall not eat of them that chew the cud and have the hoof cloven — the shesua" (Deut. 14:7). This is an animal that was born as two animals [a kind of Siamese twin].

From the scripture (Deut. 14:6): "and every beast that parts the hoof, forming thereby two entirely cloven hoofs, and ruminant [among the beasts, that may you eat.]" — I derive that everything that is not cloven-hoofed and ruminant must be forbidden. A prohibition derived from a commandment becomes a commandment. Regarding the camel, hare, and hyrax it says (Lev. 11:4; Deut. 14:7): "These you shall not eat among ruminants" — you see that they are forbidden even though they have one sign, certainly other non-kosher cattle or game that has none of the signs. The injunction against eating them is in addition to that derived commandment.

Not to eat the flesh of unclean beasts, as it is said, “Nevertheless, these shall ye not eat of them that chew the cud” or of them that divide the hoof…(Lev. 11:4).