pink dolphin

Short definition from Wiktionary

Noun

1. 1
   A subspecies of the Indo-Pacific humpback dolphin (Sousa chinensis chinensis), of the Pearl River Delta, which gain pink coloration as they age.
2. 2
   Any dolphin of the species Inia geoffrensis, of the Amazon River, males of which gain pink coloration as they age; Amazon River dolphin.