Trichechus manatus vs sea cow

Trichechus manatus and sea cow both are nouns.

Word	Noun	Adjective	Verb	Adverb
Trichechus manatus	Yes	No	No	No
sea cow	Yes	No	No	No

As nouns, sea cow is a hypernym of Trichechus manatus; that is, sea cow is a word with a broader meaning than Trichechus manatus:

Trichechus manatus: sirenian mammal of tropical coastal waters of America; the flat tail is rounded
sea cow: any of two families of large herbivorous aquatic mammals with paddle-shaped tails and flipper-like forelimbs and no hind limbs

Other hypernyms of Trichechus manatus include sirenian, sirenian mammal.

Trichechus manatus (noun)	sea cow (noun)
sirenian mammal of tropical coastal waters of America; the flat tail is rounded	any of two families of large herbivorous aquatic mammals with paddle-shaped tails and flipper-like forelimbs and no hind limbs