mammalogist vs animal scientist

mammalogist and animal scientist both are nouns.

Word	Noun	Adjective	Verb	Adverb
mammalogist	Yes	No	No	No
animal scientist	Yes	No	No	No

As nouns, animal scientist is a hypernym of mammalogist; that is, animal scientist is a word with a broader meaning than mammalogist:

mammalogist: one skilled in the study of mammals
animal scientist: a specialist in the branch of biology dealing with animals

Other hypernyms of mammalogist include zoologist.

mammalogist (noun)	animal scientist (noun)
one skilled in the study of mammals	a specialist in the branch of biology dealing with animals