poikilotherm vs fauna

poikilotherm and fauna both are nouns.

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

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

poikilotherm: an animal whose body temperature varies with the temperature of its surroundings; any animal except birds and mammals
fauna: a living organism characterized by voluntary movement

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

poikilotherm (noun)	fauna (noun)
an animal whose body temperature varies with the temperature of its surroundings; any animal except birds and mammals	a living organism characterized by voluntary movement
	all the animal life in a particular region or period