LitCharts assigns a color and icon to each theme in Life of Pi, which you can use to track the themes throughout the work.
Survival
Religion and Faith
Storytelling
Boundaries
Summary
Analysis
The constant sun and salt continues to wear down everything on the lifeboat, including Pi and Richard Parker. They both become skeletally thin, and Pi starts sleeping away most of the day, often using his dream rag. Pi writes in his diary, convinced that he and the tiger will both die soon. He touches Richard Parker for the first time when the tiger is lying motionless in a brief rainstorm. After his last diary entry, “I will die today,” Pi runs out of ink.
Pi’s writing in the diary is a kind of self-communication, or a message for some future third party, but he is thwarted in this as well by running out of ink. Even Pi’s powerful will to live and heroic resourcefulness cannot hold out forever.