mouse hare vs gnawing mammal

mouse hare and gnawing mammal both are nouns.

Word	Noun	Adjective	Verb	Adverb
mouse hare	Yes	No	No	No
gnawing mammal	Yes	No	No	No

As nouns, gnawing mammal is a hypernym of mouse hare; that is, gnawing mammal is a word with a broader meaning than mouse hare:

mouse hare: small short-eared burrowing mammal of rocky uplands of Asia and western North America
gnawing mammal: relative large gnawing animals; distinguished from rodents by having two pairs of upper incisors specialized for gnawing

Other hypernyms of mouse hare include lagomorph.

mouse hare (noun)	gnawing mammal (noun)
small short-eared burrowing mammal of rocky uplands of Asia and western North America	relative large gnawing animals; distinguished from rodents by having two pairs of upper incisors specialized for gnawing