rattler vs massasauga

rattler and massasauga both are nouns.

Word	Noun	Adjective	Verb	Adverb
rattler	Yes	No	No	No
massasauga	Yes	No	No	No

As nouns, massasauga is a hyponym of rattler; that is, massasauga is a word with a more specific, narrower meaning than rattler:

rattler: pit viper with horny segments at the end of the tail that rattle when shaken
massasauga: pygmy rattlesnake found in moist areas from the Great Lakes to Mexico; feeds on mice and small amphibians

rattler (noun)	massasauga (noun)
pit viper with horny segments at the end of the tail that rattle when shaken	pygmy rattlesnake found in moist areas from the Great Lakes to Mexico; feeds on mice and small amphibians
a railroad train consisting of freight cars	small pygmy rattlesnake