Leviticus 11:3

Whatsoever parteth the hoof, and is clovenfooted. — Better, Whatsoever is clovenfooted, and entirely separateth the hoofs. The first rule laid down by which the clean quadruped is to be distinguished is that the hoofs must be completely cloven or divided above as well as below, or, as the parallel passage in Deuteronomy 14:6 has it, “and cleaveth the cleft into two claws.” Such is the case in the foot of the ox, the sheep, and the goat, where the hoof is wholly divided below as much as above. The foot of the dog, the cat, and the lion, though exhibiting a division into several distinct toes or claws, is contrary to the regulation here laid down, inasmuch as the division is simply on the upper side, the lower side being united by a membrane, and hence the hoof is not “entirely separated.”

And cheweth the cud. — In addition to the foot being perfectly cloven, the quadruped to be clean is to be ruminating. The canon which obtained during the second Temple is thus formulated: “Every quadruped which has no upper teeth is known to be ruminant, and when it is also clovenfooted is clean.” According to the law of Manu the highest Hindoo castes were also forbidden to eat the flesh or drink the milk of quadrupeds with uncloven hoof. The same was the case with the Egyptian priests: they abstained from eating the flesh of any animal which had uncloven hoofs or many claws.