water deer vs Hyemoschus aquaticus

water deer and Hyemoschus aquaticus both are nouns.

Word	Noun	Adjective	Verb	Adverb
water deer	Yes	No	No	No
Hyemoschus aquaticus	Yes	No	No	No

As nouns, water deer and Hyemoschus aquaticus are synonyms defined as:

water deer and Hyemoschus aquaticus: largest chevrotain; of marshy areas of west Africa

Other synonyms of water deer include water chevrotain.

water deer (noun)	Hyemoschus aquaticus (noun)
largest chevrotain; of marshy areas of west Africa	largest chevrotain; of marshy areas of west Africa