narwhal vs Monodon monoceros

narwhal and Monodon monoceros both are nouns.

Word	Noun	Adjective	Verb	Adverb
narwhal	Yes	No	No	No
Monodon monoceros	Yes	No	No	No

As nouns, narwhal and Monodon monoceros are synonyms defined as:

narwhal and Monodon monoceros: small Arctic whale the male having a long spiral ivory tusk

Other synonyms of narwhal include narwal, narwhale.

narwhal (noun)	Monodon monoceros (noun)
small Arctic whale the male having a long spiral ivory tusk	small Arctic whale the male having a long spiral ivory tusk