That's really simple. Humans are at the top of the food chain. End of story.
Genesis 9:1-5 lays it right on down.
9 And God blessed Noah and his sons and said to them, Be fruitful and multiply and fill the earth. 2 The fear of you and the dread of you shall be upon every beast of the earth and upon every bird of the heavens, upon everything that creeps on the ground and all the fish of the sea. Into your hand they are delivered. 3 Every moving thing that lives shall be food for you. And as I gave you the green plants, I give you everything. 4 But you shall not eat flesh with its life, that is, its blood. 5 And for your lifeblood I will require a reckoning: from every beast I will require it and from man. From his fellow man I will require a reckoning for the life of man."
