Rainsford's philosophy about hunting is similar to Zaroff's, although Zaroff takes the philosophy much further. At the dinner table, Zaroff explains to Rainsford how he has come to live on the island and how he has become bored with hunting animals. Rainsford is shocked with Zaroff's revelation, that he hunts people:
"I refuse to believe that so modern and civilized a young man as you seem to be harbors romantic ideas about the value of human life. Surely your experiences in the war--"
"Did not make me condone cold-blooded murder," finished Rainsford stiffly.
(Connell, "The Most Dangerous Game," classicreader.com)
Rainsford still considers human life valuable, while Zaroff explicitly states that he is justifed in hunting other humans because he is stronger than they are. Zaroff initially wants Rainsford to join him in the hunt, but Rainsford refuses on moral grounds. By the end of the story, though, Rainsford has become more pragmatic, and deliberately returns to the chateau to kill Zaroff. This is not necessarily because he has become like Zaroff (although that is one interpretation) but rather a reflection of the value that he places on his own life; Rainsford wants to continue living, and is willing to lower himself to Zaroff's level to survive.