Sistrurus catenatus vs rattler

Sistrurus catenatus and rattler both are nouns.

Word	Noun	Adjective	Verb	Adverb
Sistrurus catenatus	Yes	No	No	No
rattler	Yes	No	No	No

As nouns, rattler is a hypernym of Sistrurus catenatus; that is, rattler is a word with a broader meaning than Sistrurus catenatus:

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

Other hypernyms of Sistrurus catenatus include rattlesnake.

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