This quote shows how if your a tiger then you live in a jungle and Pi fights just like tigers in the jungle. Since Richard Parker is the savage side of Pi then Pi is in a jungle and he must fight or run into death.
"Course he isn't safe. But he's good. He's the King, I tell you. Beaver, answering one of the Pevensie children's question about whether or not the lion Aslan was safe (Aslan represents God in the allegorical series The Chronicles of Narnia)