Narwhal, a toothed whale found in arctic waters near Canada and Greenland. The male narwhal has a long, spiralled tusk. The tusk is formed by the upper left canine tooth, which grows forward instead of downward and protrudes through the skin. The tusk is sometimes found on females, and some narwhals have two tusks. A narwhal's tusk is as long as nine feet (2.7 m) and is used defensively against predators. Males also use the tusk to fight other males during mating season.

A narwhal's tuskA narwhal's tusk grows up to nine feet long.

For centuries, the narwhal was widely hunted for its tusk as a source of ivory. Today, a small number are killed by Eskimos for ivory and for food. Narwhal tusks were once commonly believed to be horns from the legendary unicorns.

The narwhal is mottled brown or gray above and white below. It has a blunt snout and short flippers with rounded tips; it lacks a dorsal fin. The male reaches a length of about 20 feet (6 m) from head to tail and weighs up to 3,900 pounds (1,800 kg); the female is slightly smaller.

Narwhals live in groups of 3 to 20 individuals. They communicate by emitting a variety of sounds. Like other toothed whales, they use echolocation, which is similar in principle to sonar, to avoid obstacles and to locate food. Narwhals feed mainly on fish, squid, and shrimp.

Which Toothed Whale Has the Fewest Teeth?

The honor of being the whale with the fewest teeth goes to the narwhal. The male narwhal’s tooth, or tusk, grows to about 8 feet (2.4 meters) long. It is made of ivory. But no one is sure what the tusk is for. It may be used in fighting. Or, it may be just for show.

All narwhals lack teeth inside their mouths. They probably capture prey by sucking. And, since they can’t chew, they must then swallow the prey whole. Their prey includes fish, shrimps, and squid.

Although narwhals don’t have teeth inside their mouths, they do have teeth. Both males and females have two teeth buried in their upper jaws. Only one tooth—the left tooth of the male—ever grows so that it can be seen. But what a tooth it is!

The narwhal is Monodon monoceros of the family Monodontidae.