How does Yann Martel use indirect characterization to show that all the characters in the book change due to hard times?

Yann Martel uses indirect characterization primarily in his development of Pi; however, that effort does permeate his development of other characters as well. Given that his protagonist is also his narrator, Martel rarely uses him to comment directly on his own traits. Instead, Pi describes his actions, thoughts, behaviors, and desires.
Pi begins to realize the severity of his situation at the beginning of chapter 51 when Richard Parker's den is quite literally between him and survival. In order to survive, he must discover the supplies located at the bow of the lifeboat. He says, "My hopes for survival flickered. My thirst remained." Out of necessity, he accesses the supply chest located across Richard Parker's den and is rewarded with a bounty that causes him an almost religious ecstasy.
While this is certainly not the first time that Pi braves encroaching on the territory of the dangerous beast, his earlier attempts are categorized by fear and trepidation. He spends more time questioning the best course of action. Now, because of his incredible hardship, his survival instincts have become almost as animalistic as his shipmates'. It is not his hope for survival that drives him across the boat, but his simple and basic need for water.
It is through our observation of Pi's changed attitudes and actions as he solves problems that he develops as a character. This example of indirect characterization is also used when Pi, as a narrator telling his story, describes the actions and attitudes of others.