Torah Portion: Shemini
“זאת החיה אשר תאכלו… כל מפרסת פרסה…” (ויקרא יא ב-ג)
It is a positive commandment to inspect the signs [of kosher] animals if we wish to eat of them. The signs that they are kosher is that they chew their cud and have split hooves, as it is written, These are the creatures that you may eat…. Everything among the animals that has a split hoof etc. (Vayikra 11:2-3).
The root idea of the prohibitions related to food has been discussed above. The idea behind checking for their signs stems from the same reason as why [some creatures are] forbidden to eat: Whatever is forbidden to us should rightly be examined thoroughly.
The laws of the mitzvah include: Any domesticated type animal (beheima) or non-domesticated animal (chaya) that chews its cud does not possess upper teeth, and every animal in the world that chews its cud also has split hooves, except for the camel, and every animal that has split hooves also chews it cud, except for swine.
This commandment applies in all places and at all times, to both men and women. If a person transgressed this, and did not look for its signs, but rather saw only one of its signs and did not bother looking for the other, and ate of that animal — even if he later determined that in fact it was a species that is allowed to be eaten — violated this commandment to examine for kosher signs.