ou > au in French

[Tropylium]

Something that started bugging me: why does French have the words dauphin and vauture rather than, as might be expected, ˣdouphin and ˣvouture?

Are there other cases like this or is this just randomly u o / [+animal]?

[Legion]

"dauphin" is from vulgar latin *dalphinus, from classical delphinus. The expected form from the classical etymon would be *deuphin or *deauphin, not *douphin

"vautour" is due to dialectal influence.