barker vs Canis familiaris

barker and Canis familiaris both are nouns.

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

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

barker: informal terms for dogs
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 barker include dog, domestic dog.

barker (noun)	Canis familiaris (noun)
informal terms for dogs	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
someone who stands in front of a show (as at a carnival) and gives a loud colorful sales talk to potential customers