Which small whale is known as the 'canary of the sea'?

The small whale known as the “canary of the sea” is the beluga. Belugas earned this nickname because their high-pitched squeaks, whistles, clucks, and squeals can sound remarkably like bird calls.

The beluga whale, Delphinapterus leucas, is an Arctic and sub-Arctic toothed whale. Its genus name means “dolphin without a fin,” referring to its lack of a dorsal fin, an adaptation that may help it travel beneath sea ice. Adults are usually white, making the species the only cetacean that regularly occurs in this color.

Belugas are unusually vocal and communicate using a broad range of sounds. They also have a flexible, movable neck and a rounded forehead called a melon, which helps focus sound during echolocation. These features make them especially recognizable among northern whales.

A common mix-up is the narwhal, the beluga's closest living relative. Narwhals are also Arctic monodontids, but they are famous for their long tusks rather than their song-like calls. The phrase “sea canary” specifically points to the beluga.