Beluga whales and narwhals are the only two living species in this family. Although they look quite different, these species share certain physical characteristics, including a very small beak and small head. Their neck bones (cervical vertebrae) are not fused or joined together, giving them the ability to turn their head without turning their entire body. Neither species has a dorsal (back) fin, only a ridge where the fin normally is found. The lack of a fin is unusual in whales. Members of this family range in size from 13 to 16 feet (4 to 5 meters) and in weight from 1,500 to 3,500 pounds (680 to 1,600 kg).

Both species change color as they age. Belugas are born gray, but gradually become white by the time they reach maturity at seven to nine years. Narwhals are born gray. As young animals, they become almost completely blue-black. In adulthood they become mottled (spotted) dark gray, with more dense splotches on the back and less dense ones on the belly. In old age, they become white.

The main difference in these species is in their teeth. Belugas have simple teeth in both the upper and lower jaw. Narwhals have only two teeth in the upper jaw. In females, these teeth do not erupt or become visible. In males, one tooth becomes a spiraled tusk that may be 10 feet (3 meters) long.


Both these species live in the Arctic oceans, although their distribution is not continuous.


Narwhals live in deep water farther north than any other whale, following the ice pack as it grows and recedes. Beluga whales live in shallower water and are sometimes found farther south. In the summer, they move into estuaries (places where rivers empty into the ocean). They can survive in fresh water and have occasionally been found swimming hundreds of miles (kilometers) up river from the ocean.


Both these species are bottom feeders, diving deep to eat squid, fish, and shrimp. Narwhals have a more limited diet than belugas.


Both narwhals and beluga whales live in small groups or pods, although these pods may gather in groups of hundreds or thousands of animals during migrations. These species are social and communicate with a wide range of sounds. Both species migrate. The narwhal follows the ice pack, moving north as it melts in summer and south as it grows in winter. The migration of belugas appears to be triggered by day length. Not all groups of belugas migrate. One well-studied group that live at the mouth of the St. Lawrence River in Canada appears to stay there year round.

These whales give birth to a single calf at a time after a pregnancy lasting thirteen to sixteen months. The calf nurses, feeds on breast milk, and remains dependent on its mother for up to two years. Mating usually occurs in late winter or early spring and births occur in the summer of the following year.


The native people of the Arctic, the Inuit, have hunted narwhals and beluga whales for hundreds of years. These animals are an important part of their diet and culture. Both species have also been hunted commercially.


Beluga whales are considered Vulnerable, facing a high risk of extinction, dying out. Not enough is known about the size of the narwhal population to give them a conservation rating. All narwhals that have been taken into captivity have lived only a few months. However, beluga whales do well in captivity and are often exhibited at marine parks.