Answer:
By killing hyena and as a companion.
Explanation:
Richard Parker who is a Bengal tiger helps pi to survive his 227 days in the vast ocean on the boat by giving a reason to pi to live in a extremely bad conditions. First Richard Parker save the life of pi by killing hyena who is attacking on pi. Richard Parker is the only companion of pi in the vast ocean which make easier for pi to survive his 227 days. So for that reason pi also wanted to save the life of Richard Parker by providing food such as fish and drinking water and also trained him in order to use it for his own requirement.