Why is one animal clean and the other unclean?


You may eat any animal that has a divided hoof and that chews the cud.  Leviticus 11:3
 “Of all the creatures living in the water of the seas and the streams you may eat any that have fins and scales.”  Leviticus 11:9
            You are what you eat.  If that’s true, then we can defile ourselves by the food we consume.  Certain animals were unclean because of what the animals ate (trash, decomposing bodies, bottom-feeders, animal droppings) like the pig, vulture and lizard.  They could pass along certain diseases through their meat.  God had their health and safety in mind.
The point of these regulations had a spiritual significance too:
I am the Lord, who brought you up out of Egypt to be your God; therefore be holy, because I am holy.  Leviticus 11:45
            Holiness means to stay away from whatever is unclean.  God told the Israelites to think about this whenever they ate.  God wanted them to think clean, eat clean and live clean.