Called a sea-goose (oie de mer) from the form of its snout, termed in French bec d'oie (a goose's beak). The dolphin is noted for its changes of colour when taken out of the water.
Parting day Dies like the dolphin, whom each pang imbues With a new colour as it gasps away, The last still loveliest.
(The), in mediæval art, symbolises social love.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894