Gunnar and Shadow both have black spots on their tongue and a lot of black on the roof of their mouth. Cass has none on her tongue and a bit of black on the roof of her mouth.
Some of the comments reminded me that my grandfather swore by the fact that only a dog with black in its mouth was worth anything. The more black, the better.
Don't know where that ever came from, but that was his thinking.
He is your friend, your partner, your defender, your dog. You are his life, his love, his leader. He will be yours faithful and true~ to the last beat of his heart. You owe it to him to be worthy of such devotion. ~unknown