Blue-black tongues in dog breeds

Question
What are all the breeds that could have a solid blue-black tongue and gums? We are looking to adopt a dog from our local shelter and they are calling it a lab mix. However, the puppy is very healthy and may be some sort of lab but does not look like a chowchow. He is solid black with a blue-black tongue and gums.

Answer
Other then chows,Shiba Inus,Akitas and Shar Pies can have black tongues

Sometimes other dog will just have back tongues at random and is hard to tell what breed they are on that along-I have even seen a Scottish Terrier with black spots on it's tongue,so a lot of the time it's just there markings