hooded seal vs hair seal

hooded seal and hair seal both are nouns.

Word	Noun	Adjective	Verb	Adverb
hooded seal	Yes	No	No	No
hair seal	Yes	No	No	No

As nouns, hair seal is a hypernym of hooded seal; that is, hair seal is a word with a broader meaning than hooded seal:

hooded seal: medium-sized blackish-grey seal with large inflatable sac on the head; of Arctic and northern Atlantic waters
hair seal: any of several seals lacking external ear flaps and having a stiff hairlike coat with hind limbs reduced to swimming flippers

Other hypernyms of hooded seal include earless seal, true seal.

hooded seal (noun)	hair seal (noun)
medium-sized blackish-grey seal with large inflatable sac on the head; of Arctic and northern Atlantic waters	any of several seals lacking external ear flaps and having a stiff hairlike coat with hind limbs reduced to swimming flippers