Narwhal Facts

The narwhal inspired unicorn legends with its unique tusk—a spiraled, elongated tooth reaching up to 3.0 meters (10 feet). Traditionally thought to aid in male dominance displays or jousting, recent studies suggest the tusk is highly sensitive, with millions of nerve endings. Narwhals may use it to sense water salinity, which is crucial for survival in icy environments. The tusk’s asymmetric growth, unique morphology, and placement remain enigmatic, blending scientific intrigue with Inuit myths. 

Males weigh 1,600 kg (3,500 lbs) at maturity; females weigh 1,000 kg (2,200 lbs) at maturity.

At birth, 160 cm. Females: 360 cm at sexual maturity, 400 cm at physical maturity. Males: 420 cm at sexual maturity, 475 cm at physical maturity.

Infant narwhal are grey or grayish brown.  After two years, the skin becomes more mottled with overlapping white patches, and the grey becomes more blackened.  Adults are white on the ventral (belly) side, and white and mottled on the dorsal (back) side.  Older adults have only a narrow, dark triangular band extending from the back of the neck at its widest portion to a point ending on the midline of the back.

Monodon monoceros by Linnaeus in 1758 from the Greek: “one-tooth one-horn.” The word narwhal in Western culture is derived from the Old Norse “naar,” meaning cadaver or corpse. In Inuktuit, narwhal is described as “Qilalugaq gernertaq,” which translates to “the one that is pointing to the sky.”

Narwhals use sound to communicate, hunt, navigate, and see. Narwhals use their melon to focus sounds reflected off the front of their skull. They can also adjust the pitch and duration of their calls to maximize sound propagation in different environments.

Narwhals have a wide variation of clicks and whistles. Click amplitudes range from 19 to 48 kHz.  Click rates vary from 3-150 clicks per second. Whistle amplitudes range from 300 to 18 kHz.

Narwhal are most closely related to the beluga whale; they are the only two members of the family Monodontidae. Together with dolphins (Delphinoidea) and porpoises (Phocoenidae), they comprise the Superfamily Delphinoidea.

Narwhals feed on Greenland halibut, Arctic cod, polar cod, squid, and shrimp, hunting along the ice floe edge and in ice-free waters during the summer. Since they do not have teeth in their mouth, narwhals are suction feeders that swallow their prey whole.

The narwhal gestation period is estimated at 14 months. Though many scientific references indicate that mating occurs primarily in the spring, Inuit traditional knowledge interviews suggest that mating occurs throughout the year, “ like us.”  Narwhal of differing ages are present during the same summer migration, indicating that births occur throughout the year. Hunters know how many births have occurred over the life of a harvested female by anatomical markings in the female uterine tract.

Calves stay with their mother up to 20 months.

Do narwhal use their tusk aggressively to establish dominance? According to scientific findings by Silverman and Dunbar (1980), perhaps yes, as evidenced by head scarring and the prevalence of broken tusks.  Inuit hunters have not witnessed any aggressive encounters between males and account for broken tusks occurring during their hunt by killer whales or humans.  Narwhals may break their tusks during shallow dives to escape.

Age determination has been estimated by isotope analysis of differentiating growth layers of teeth formed by seasonal variability of nitrogen levels (levels are high in red rings, low in white rings). Other techniques use aspartic acid racemization, which mathematically compares eye lens nuclei and growth rings of teeth.  The oldest documented female narwhal was found to be 115 years old, although the average lifespan of the narwhal is closer to 50 years.

Narwhals do not have a dorsal fin, possibly an evolutionary adaptation to swimming easily under ice. In addition, the neck vertebrae of the narwhal are not fused together, but are jointed, like those of land mammals. According to Inuit traditional knowledge, the thickness of skin on mattak is characteristically different in the spring compared to the fall. Spring mattak is thicker and slightly softer than a thinner, firmer mattak in the fall, partially due to summer molting.

The differences in fluke form for males and females may account for females making deeper dives at a faster speed than males, and for the ability of males to increase their thrust as a means to compensate for the increased drag that their tusk exerts while swimming

Narwhals commonly dive to 500 meters, though they can dive in excess of 1,500 meters for more than a 25-minute period. Inuit hunters have documented dive times up to 40 minutes. Though one may intuitively associate deeper diving with colder water, the Arctic Ocean has beneath it sub-Atlantic waters which are warmer.  These two oceans are separated by a dense salt layer referred to as the halocline layer.

The reason why narwhals don't fare well in captivity is not perfectly clear. It's fairly common to see their closest living relative, the beluga whale, in aquarium tanks where they appear to live (relatively) happy and long lives. However, it is evident that narwhals are exceptionally sensitive animals.

Narwhals have endured periods of extreme environmental variability, including glaciations that once covered their entire habitat with ice. However, rising sea ice levels may now limit the winter habitats available to them. This shift could increase their vulnerability to mortality, as they risk entrapment within the expanding ice.

Underwater noise pollution from shipping, industrial extraction, marine construction, and military activities disrupts the acoustic environment that whales rely on for communication. This interference can hinder their ability to locate food, find mates, navigate, avoid predators, and care for their young, potentially harming their survival and well-being.