Ursus arctos horribilis vs Ursus horribilis

Ursus arctos horribilis and Ursus horribilis both are nouns.

Word	Noun	Adjective	Verb	Adverb
Ursus arctos horribilis	Yes	No	No	No
Ursus horribilis	Yes	No	No	No

As nouns, Ursus arctos horribilis and Ursus horribilis are synonyms defined as:

Ursus arctos horribilis and Ursus horribilis: powerful brownish-yellow bear of the uplands of western North America

Other synonyms of Ursus arctos horribilis include grizzly, grizzly bear, silver-tip, silvertip.

Ursus arctos horribilis (noun)	Ursus horribilis (noun)
powerful brownish-yellow bear of the uplands of western North America	powerful brownish-yellow bear of the uplands of western North America