Foreshadowing is seen early on, when Rainsford and Whitney discuss the morality of hunting. Both are skilled hunters, but Whitney is more empathic towards the prey animals, while Rainsford is more contemptuous:
"This hot weather is making you soft, Whitney. Be a realist. The world is made up of two classes -- the hunters and the huntees. Luckily, you and I are hunters."
(Connell, "The Most Dangerous Game," classicreader.com)
This mindset, that the laws of nature are made to favor the strong and allow the strong to prey on the weak, is seen later in Zaroff's philosophies. While Rainsford simply thinks that thinking man is superior of animals to the extent allowed by hunting -- that is, intelligent man is allowed to hunt animals because they cannot think as humans do -- Zaroff takes the philosophy to its extreme, believing that the strong among humans, including himself, have a moral right to hunt other humans. Rainsford finds out the hard way that rationalizing hunting more than food or fun is a slippery slope.