Pi's training of Parker is only successful because Parker does not actually want to attack him: all animals know that the risks of physical violence are great, so they avoid it when possible, Pi notes.
Pi's greatest wish, above salvation, is for a book - but all he has is his survival manual and the diary he keeps for himself. He adapts his religious rituals to the circumstances, and does his best to fight the despair that so often comes. On what he estimates is his mother’s birthday, Pi sings happy birthday to her.
Pi notices that Richard Parker tries to hide his feces, which is a sign of deference to Pi, so he makes a show of collecting the feces as a psychological ploy.
Pi’s store of survival rations diminishes, and so he has to eat less and less. His mood grows more and more closely associated with how big a meal he has been able to have. One time he even goes so far as to try to eat Richard Parker’s feces, but he can tell that there is nothing nutritious in it, so he spits it out.
The sharks are always around, but never do anything that really threatens Pi, and so he grows to like them. One day he manages to pull a smaller shark into the boat, where it gets into a battle with Richard Parker. After that Pi only goes for the baby sharks, which he kills by stabbing in the eye.
One day, while a school of flying fish is jumping over the boat, Pi manages to catch a dorado, and faces off with Richard Parker over it. Richard Parker eventually backs down, and Pi feels that his mastery of the tiger is complete.
It is not just Pi's use of seasickness that keeps Richard Parker from killing him, but the fact that Richard Parker is a zoo animal, and Pi was his source of fresh food and water most of the time.
Pi explains that the scarcity of fresh water is the largest problem throughout his entire journey. He also has to give most of his food to Richard Parker, so he learns to eat more indiscriminately and quickly.
One day comes a storm worse than any Pi has faced. Pi is forced to roll the tarpaulin down and get under it, and into Richard Parker’s territory, to avoid drowning. The storm lasts all day and into the night, and when it finally ends Pi realizes that his raft is gone except for a piece or two. The boat also is damaged, and much of the food and supplies are lost. Luckily, one whistle remains.
Pi describes the whales that he sees, which always lift his spirits. He and Parker are also visited fairly regularly by dolphins, and very rarely by birds, one of which Pi manages to kill.
In this section, we see Pi’s continued descent toward the bestial. As the food becomes scarcer, he notices that his own eating has come to resemble Richard Parker’s—fast, savage, indiscriminate. He also becomes more courageous in his choice of prey, going after baby sharks, and at one time even an adult shark.
This section also shows Pi achieving real dominance over Richard Parker. Richard Parker tries to hide his feces from Pi and backs down when Pi fights him for a dorado—all signs that, even as Pi is becoming more animal-like himself, he is dominating Richard Parker more fully. Thus, although it required intellect for Pi to tame Richard Parker, it seems the primal survival instinct in Pi - the animal in him - is more powerful and potentially more useful.
This section also stresses Pi's proximity to death. The storm is the primary example: Pi is saved by luck but left with only one whistle; that whistle in turn represents all that stands between life and death at the jaws of Richard Parker.
That said, Martel does dwell here on the more peaceful side of the animal kingdom as well. The whales, dolphins, and even sharks come to provide a kind of companionship for Pi. His description of these animals, however, further emphasizes how much his struggle for survival has altered him. Even when it comes to the peaceful dolphins and beautiful birds, Pi thinks of animals as, above all, possible food.
This seems to foreshadow what will come with the introduction of the Frenchman, when Pi descends so far as to eat human flesh. Of his animal companions, only Richard Parker is still safe from becoming Pi’s food, because Pi would be incapable of killing him. But as animals that Pi would never have considered killing and eating in his past life become possible meals, the line between friend and food grows blurred, making the possibility of eating human flesh later less extreme.