mutt vs Canis familiaris

mutt and Canis familiaris both are nouns.

Word	Noun	Adjective	Verb	Adverb
mutt	Yes	No	No	No
Canis familiaris	Yes	No	No	No

As nouns, Canis familiaris is a hypernym of mutt; that is, Canis familiaris is a word with a broader meaning than mutt:

mutt: an inferior dog or one of mixed breed
Canis familiaris: a member of the genus Canis (probably descended from the common wolf) that has been domesticated by man since prehistoric times; occurs in many breeds

Other hypernyms of mutt include dog, domestic dog.

mutt (noun)	Canis familiaris (noun)
an inferior dog or one of mixed breed	a member of the genus Canis (probably descended from the common wolf) that has been domesticated by man since prehistoric times; occurs in many breeds