In the Mosaic Law, the clean animals are the ones that both chew the cud and split the hooves. I understand why animals that chew the cud are clean — they eat grass, not other animals or dirty things — but what does the split hoof mean? Do animals with split hooves also tend to have multiple stomachs to filter out toxins?
The two characteristics seem to go together. Rabbi Avraham Arieh Trugman from www.askmoses.com explained it this way. “The ten kosher animals listed in the Torah all have both split hooves and chew their cud. What all these animals have in common is that they all graze for food and are not predators. Although the Torah permits man to eat animals, a Jew is commanded to do so only under very strict limits, such as eating only certain animals that undergo the prescribed slaughtering and have all the blood removed. In addition, the only animals permitted are those who don’t kill other animals. We are what we eat and the Torah does not want us to take into our beings the very essence of the animal, especially if its very nature is connected to killing.”