When an impure animal appears to be born to a pure animal, the animal can be consumed if and only if its head and more resembles the kosher mother. But can a kosher animal and a non-kosher animal truly mate? It seems not. To the extent that an animal that looks like it’s the progeny of both perhaps may have been born of two kosher animals, but where one had a mutation to look like a non-kosher animal. Also, the question of how practical the concern was about this kind of progeny of kosher-and-non-kosher animals. Plus, a new mishnah! On fish, where the non-kosher fish swallowed a kosher fish or the reverse. Note that the distinction between non-kosher fish (usually sea creatures or sea food) and kosher fish is the difference between spawning progeny vs. laying eggs.

The link to Dr. Jeremy Brown’s Talmudology post: ⁠https://www.talmudology.com/jeremybrownmdgmailcom/2016/8/14/pigxsheep-y7df4⁠