Within the Kosher diet, much attention is devoted to the animal kingdom. There are commandments which instruct just what may be eaten, and what must be avoided. The Torah requirements for animals and fish are well known. A kosher quadruped must have split hooves and chew its cud. Only fish which have both fins and scales are permitted to be consumed. But what constitutes a kosher bird?
In truth, the Torah does not provide any signs to identify a kosher fowl. No objective criteria is given to differentiate between the acceptable from the non-accepted, rather the Scripture enumerates twenty-four families of birds which are prohibited. Perhaps one may be deluded into thinking; because there is no code with which to determine which are Kosher, the Torah is restricted to listing. But this is far from true, our Sages in the Mishna found a method to ascertain whether a fowl is kosher. This is by utilizing four signs to verify if a bird is outlawed.
1. ‘Doreis’ – if it possess predatory eating habits it is not kosher.
Additionally, kosher birds have three physical characteristics:
2. An extra toe in the back which helps support the leg
3. A crop for storing food prior to digestion.
4. A gizzard with a peelable lumen (lining). (Chullin 3:6)
Why the difference? Why when dealing with the beasts and fish does the Torah prefer to give a formula to establish which are kosher, however in regards to the birds, it opts to record them in detail, leaving the markers to the Rabbis. Additionally, we know the Torah is concise, writing only what is absolutely necessary, so why spend many a word tabulating different species of flying creatures?
There is a fundamental difference between the signs for animals and birds. Although both have symbols hinting at their status, the rationale behind the birds’ signs is different from the beasts. This will develop from understanding the depth behind the kosher symbols.
What is it about these mammals that determine their status? What is the difference if the hoof is split?
The consumption of all matter, writes the Vilna Gaon, breeds the temperament of the food in it’s host. Eating angry birds will make you an angry person. Some animals are greedy, wild and aggressive and they will generate likewise habits in the human that eats them. Secondly he writes, the source of all sins and transgression are rooted in lust. It is paramount to avoid tendencies which nurture desire.
The preying bird demonstrates a lack of satisfaction. A predatory nature is incompatible with the characteristic of contentment. That is why we not eat any bird which is ‘doreis’ – a fowl which attacks. This too says the Vilna Gaon sheds light on why kosher beasts must chew the cud and have split hooves. Re-chewing the food is symbolic of sufficing with the food already absorbed. Split hooves are evidence that it does not chase and kill, but is nourished on the trough of it’s master.
Thus non-kosher animals which do not ruminate their food or possess split hooves, are black listed because they are missing the correct signs. Not because it fails to have the zoological anatomy to accurately convey that the mammal as kosher. There is much more to this. Lacking these signs are actual reasons for its impurity. The missing signals highlight it’s immoral nature because missing a kosher sign is tantamount to saying it has covetous character.
Not so when it comes to the flying animals. Yes there are hints to verify if the bird is kosher, these are but useful markers to establish its status. As a rule they are not absolutely indicative of a lasciviousness nature. What is wrong if the lining of its gizzard does not peel, does this point to any wicked tendencies. Therefore to Torah prefers the lengthy route of enumerating the non-kosher families over providing ornithological signals.