pachyderm vs placental mammal

pachyderm and placental mammal both are nouns.

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

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

pachyderm: any of various nonruminant hoofed mammals having very thick skin: elephant, rhinoceros, hippopotamus
placental mammal: mammals having a placenta; all mammals except monotremes and marsupials

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

pachyderm (noun)	placental mammal (noun)
any of various nonruminant hoofed mammals having very thick skin: elephant, rhinoceros, hippopotamus	mammals having a placenta; all mammals except monotremes and marsupials