mara vs gnawer

mara and gnawer both are nouns.

Word	Noun	Adjective	Verb	Adverb
mara	Yes	No	No	No
gnawer	Yes	No	No	No

As nouns, gnawer is a hypernym of mara; that is, gnawer is a word with a broader meaning than mara:

mara: hare-like rodent of the Pampas of Argentina
gnawer: relatively small placental mammals having a single pair of constantly growing incisor teeth specialized for gnawing

Other hypernyms of mara include rodent.

mara (noun)	gnawer (noun)
hare-like rodent of the Pampas of Argentina	relatively small placental mammals having a single pair of constantly growing incisor teeth specialized for gnawing