In The Alchemist, what omen does Santiago see in the desert?

There are two omens mentioned in The Alchemist. The first, for Santiago, is Fatima's smile. When Santiago first meets Fatima, she smiles at him, and he immediately falls in love with her. He calls Fatima's smile "the omen he had been awaiting" and "the omen he had sought to find . . . in the silence of the desert." Fatima's smile is for Santiago an omen of true love, "the pure language of the world."
A little later in the story, there is a second omen. In the desert, Santiago's horse begins to slow down, and he knows that this means there is something else alive nearby. Santiago, with the alchemist and the Englishman, finds a deep hole. The alchemist puts his hand into the hole up to his shoulder and feels something moving. When the alchemist pulls his arm out of the hole, he is holding a snake by its tail. He says that this snake is an omen because it is "life in the desert." The snake is a symbol of life and, therefore, a symbol of hope.