prey vs fauna

prey and fauna both are nouns.

Word	Noun	Adjective	Verb	Adverb
prey	Yes	No	Yes	No
fauna	Yes	No	No	No

As nouns, fauna is a hypernym of prey; that is, fauna is a word with a broader meaning than prey:

Other hypernyms of prey include animal, animate being, beast, brute, creature.

prey (noun)	fauna (noun)
animal hunted or caught for food	a living organism characterized by voluntary movement
a person who is the aim of an attack (especially a victim of ridicule or exploitation) by some hostile person or influence	all the animal life in a particular region or period

prey (verb)	fauna (verb)
profit from in an exploitatory manner
prey on or hunt for