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
Pi survives on very little sleep, and usually only gets about an hour at a time. Richard Parker, on the other hand, sleeps all the time in various favorite positions.
With these short chapters Martel recreates the blurring of time that Pi experiences, a monotony of suffering only occasionally interrupted.