black bear vs Euarctos americanus

black bear and Euarctos americanus both are nouns.

Word	Noun	Adjective	Verb	Adverb
black bear	Yes	No	No	No
Euarctos americanus	Yes	No	No	No

As nouns, black bear and Euarctos americanus are synonyms defined as:

black bear and Euarctos americanus: brown to black North American bear; smaller and less ferocious than the brown bear

Other synonyms of black bear include American black bear, Ursus americanus.

black bear (noun)	Euarctos americanus (noun)
brown to black North American bear; smaller and less ferocious than the brown bear	brown to black North American bear; smaller and less ferocious than the brown bear
bear with a black coat living in central and eastern Asia