digitigrade mammal vs placental

digitigrade mammal and placental both are nouns.

Word	Noun	Adjective	Verb	Adverb
digitigrade mammal	Yes	No	No	No
placental	Yes	Yes	No	No

As nouns, placental is a hypernym of digitigrade mammal; that is, placental is a word with a broader meaning than digitigrade mammal:

digitigrade mammal: an animal that walks so that only the toes touch the ground as e.g. dogs and cats and horses
placental: mammals having a placenta; all mammals except monotremes and marsupials

Other hypernyms of digitigrade mammal include eutherian, eutherian mammal, placental mammal.

digitigrade mammal (noun)	placental (noun)
an animal that walks so that only the toes touch the ground as e.g. dogs and cats and horses	mammals having a placenta; all mammals except monotremes and marsupials

digitigrade mammal (adjective)	placental (adjective)
	pertaining to or having or occurring by means of a placenta