Crotalus tigris vs rattlesnake

Crotalus tigris and rattlesnake both are nouns.

Word	Noun	Adjective	Verb	Adverb
Crotalus tigris	Yes	No	No	No
rattlesnake	Yes	No	No	No

As nouns, rattlesnake is a hypernym of Crotalus tigris; that is, rattlesnake is a word with a broader meaning than Crotalus tigris:

Crotalus tigris: having irregularly cross-banded back; of arid foothills and canyons of southern Arizona and Mexico
rattlesnake: pit viper with horny segments at the end of the tail that rattle when shaken

Other hypernyms of Crotalus tigris include rattler.

Crotalus tigris (noun)	rattlesnake (noun)
having irregularly cross-banded back; of arid foothills and canyons of southern Arizona and Mexico	pit viper with horny segments at the end of the tail that rattle when shaken