Rainsford won the wager. He fought Rainsford in the bedroom and Zaroff got fed to his own dogs. I suppose when Rainsford is in a tree and reflects that this is how an animal must feel to be hunted tips us off that he has a new attitude. The story, however, is so bizarre that the theme isn't dealt with in any depth. Perhaps Rainsford might think a little more about hunting defenseless animals in the future but I doubt he would start an animal rights movement.
to tell when and where the story takes place to explain how difficult it is to travel in some climates to show how dangerous it is to leave Honduras to introduce the main character and describe his traits.