swamp hare vs cottontail rabbit

swamp hare and cottontail rabbit both are nouns.

Word	Noun	Adjective	Verb	Adverb
swamp hare	Yes	No	No	No
cottontail rabbit	Yes	No	No	No

As nouns, cottontail rabbit is a hypernym of swamp hare; that is, cottontail rabbit is a word with a broader meaning than swamp hare:

swamp hare: a wood rabbit of southeastern United States swamps and lowlands
cottontail rabbit: common small rabbit of North America having greyish or brownish fur and a tail with a white underside; a host for Ixodes pacificus and Ixodes scapularis (Lyme disease ticks)

Other hypernyms of swamp hare include cottontail, wood rabbit.

swamp hare (noun)	cottontail rabbit (noun)
a wood rabbit of southeastern United States swamps and lowlands	common small rabbit of North America having greyish or brownish fur and a tail with a white underside; a host for Ixodes pacificus and Ixodes scapularis (Lyme disease ticks)