round-tailed muskrat vs rodent

round-tailed muskrat and rodent both are nouns.

Word	Noun	Adjective	Verb	Adverb
round-tailed muskrat	Yes	No	No	No
rodent	Yes	No	No	No

As nouns, rodent is a hypernym of round-tailed muskrat; that is, rodent is a word with a broader meaning than round-tailed muskrat:

round-tailed muskrat: of Florida wetlands
rodent: relatively small placental mammals having a single pair of constantly growing incisor teeth specialized for gnawing

Other hypernyms of round-tailed muskrat include gnawer.

round-tailed muskrat (noun)	rodent (noun)
of Florida wetlands	relatively small placental mammals having a single pair of constantly growing incisor teeth specialized for gnawing