from a french dictionary
dauphin m. [hist.] the Dauphin - from 1349 to 1830 Title of french heir to the throne, before that ruler of the Dauphiné.
dauphin m. [zool.] the Dolphin
dauphin m. [hist.] the successor ( or Crowne Prince )
dauphin m. [sport.] the second best (cycling)
I figure since all the others are animals why should this one be different?
GG