Which breed is known for a blue-black tongue?

The story behind the answer

Chow Chow is correct because a blue-black tongue is this breed’s signature trait. The dark color comes from heavy melanin pigmentation in the tongue and oral tissues, typically visible from puppyhood and even used by breed judges as a hallmark of purebred Chows.

Fun context: The Chow Chow is an ancient Chinese breed, and a popular legend says it got its dark tongue from licking the night sky. While other dogs can have dark spots on the tongue—and the Shar Pei can also show a bluish tongue—the Chow Chow is the classic “blue-black tongue” poster breed. Memory tip: “Chow your charcoal”—Chow Chow = charcoal-colored tongue.