ectotherm vs creature

ectotherm and creature both are nouns.

Word	Noun	Adjective	Verb	Adverb
ectotherm	Yes	No	No	No
creature	Yes	No	No	No

As nouns, creature is a hypernym of ectotherm; that is, creature is a word with a broader meaning than ectotherm:

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

Other hypernyms of ectotherm include animal, animate being, beast, brute, fauna.

ectotherm (noun)	creature (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
	a living being
	a person who is controlled by others and is used to perform unpleasant or dishonest tasks for someone else