In Life of Pi, how does Richard Parker ensure that Pi survives his ordeal at sea?I would like at least four reason why if possible. Quotes don't...

Richard Parker keeps Pi vigilant. Pi must always be on his
toes, always working to fish, collect water, and maintain his life raft for his own
survival and to keep Richard Parker happy. Pi keeps Richard Parker happy because if he
doesn’t, he believes Richard will eat him, which means sustaining the supply of food and
water.  Remember the passages where Pi talks about different species learning to live
together in the zoo. They do what they need to survive. I think he referred to this as
zoomorphism; when one animal sees an animal of another species (even a human) as a
member of its own species. Pi also appeases Richard Parker out of loneliness. A
relationship is a relationship even if it is based on fear and
uncertainty.

Earlier in the novel, Pi notes the danger of
seeing an animal as human-like. In an ironic twist, Pi does the opposite with the cook.
But he did so in order to maintain a zoomorphic relationship with him/Richard Parker.
Treating his relationship with Richard Parker as two different species living together
as if they were the same species allowed him to maintain a skeptical symbiotic
relationship. This is what allowed Pi to survive.

Pi’s love
of all religions is applicable here too. He saw the different religious narratives as
equally valid and applicable in different circumstances. Likewise, Pi created his own
narrative in order to survive. Real or not, Richard Parker was his religious allegory,
which gave him the right perspective on his situation in order to survive. Richard
Parker kept him company, kept him aware and forced him to structure his day
meticulously, which ensured his survival and really kept him from losing his mind. As
long as he was busy, he would not have time to dwell on the hopelessness of his
situation.