I have read where animals and birds do not cry or shed tears like humans. Animals and birds do not have the same sensitivity level nor intelligence of man. Animals and birds have no spirituality or moral principles or values. These creatures do not have mental institutions, psychiatrists or psychologists. Since man has a greater capacity for grief, anxiety, and perplexity, he, therefore, needs a greater capacity for release of grief and burdens.
Tears are part of the release of grief.
Therefore, Saul planned to kill David. He chased David to Gath where king Achish of the Philistines ruled. He was afraid for his life, not only with King Saul, who was a child of God, but also with king Achish, who was not a child of God. It is bad enough to have people who are out to get you outside of the church, but when you have this on the inside, too, it is even worse. The primary reason that man has to shed tears is that he may learn to trust in God.