swamp hare vs cottontail

swamp hare and cottontail both are nouns.

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

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

swamp hare: a wood rabbit of southeastern United States swamps and lowlands
cottontail: 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 rabbit, wood rabbit.

swamp hare (noun)	cottontail (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)