work animal vs creature

work animal and creature both are nouns.

Word	Noun	Adjective	Verb	Adverb
work animal	Yes	No	No	No
creature	Yes	No	No	No

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

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

work animal (noun)	creature (noun)
an animal trained for and used for heavy labor	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