When god created the world, one dog was allowed to lick up the pieces of sky that fell to earth as the stars were set in place. That dog was the chow, and ever since chows have had blue tongues – Li Fu (East Asian Legend)
Chow Chows are known for their blue-black tongue but did you know that their tongue is actually pink at birth? At 8 to 10 weeks of age, it starts turning blue-black/purple. Some Chows retain splashes of pink. This blue-black/purple appears to be a dominant trait, with mixed breeds of Chows also having this characteristic. Of course this is not to say that every dog with a blue-black/purple tongue is related to the Chow. Other breeds like the Sharpei also have dark tongues.