What is the relation of the old man to the sea?

Hemingway focuses on the connections between Santiago and his natural environment: the fish, birds, and stars are all his brothers or friends; he has the heart of a turtle, eats turtle eggs for strength; anddrinks shark liver oil for health. This connection with the sea and its creatures helps Santiago in the midst of his great tragedy. For Santiago, success and failure are two equal facets of the same existence. They are transitory forms which capriciously arrive and depart without affecting the underlying unity between himself and nature. As long as he focuses on this unity and sees himself as part of nature rather than as an external antagonist competing with it, he cannot be defeated by whatever misfortunes befall him.