bowhead whale vs bowhead

bowhead whale and bowhead both are nouns.

Word	Noun	Adjective	Verb	Adverb
bowhead whale	Yes	No	No	No
bowhead	Yes	No	No	No

As nouns, bowhead whale and bowhead are synonyms defined as:

Other synonyms of bowhead whale include Balaena mysticetus, Greenland whale.

bowhead whale (noun)	bowhead (noun)
large-mouthed Arctic whale	large-mouthed Arctic whale