There is irony in the fact that Rainsford, a famous hunter, is being humted. Also Rainsford finally realizes what an animal would experience while being hunted. Consider the irony in this short conversation between Rainsford and Whitney:
"For the hunter," amended Whitney. "Not for the jaguar."
"Don't talk rot, Whitney," said Rainsford. "You're a big-game hunter, not a philosopher. Who cares how a jaguar feels?" "Perhaps the jaguar does," observed Whitney.
The irony of the hunter becoming the hunted ties in with the theme of animals having emotions and understanding panic, fear, terror....