Pelorus Jack, a famous Risso's Dolphin from New Zealand.
From Pelorus Jack: the White Dolphin of French Pass, New Zealand by J Cowan, 1911 (photo taken by Capt. C. F. Post, of the N.Z. Govt. SS Tutanekai).
Source: https://commons.wikimedia.org/wiki/File:Pelorus_Jack.jpg

Risso's dolphin (Grampus griseus) is a species of dolphin in the family Delphinidae. It is commonly known as the Monk dolphin among Taiwanese fishermen. Risso's dolphins are found worldwide in temperate and tropical waters, usually in deep waters rather, but close to land.