9 Pointed Facts About Narwhals

Narwhals were once thought to be unicorns of the sea thanks to their gigantic left teeth.
Not a unicorn.
Not a unicorn. / Dorling Kindersley/Dorling Kindersley RF/Getty Images (narwhal), Rizky Panuntun/Moment/Getty Images (background)

The meme sums it up: Narwhals, swimming in the ocean and causing a commotion, really are awesome. The “unicorns of the sea” have fascinated mariners and royalty for centuries, yet scientists still don’t understand some keys details about the Arctic whales’ life cycle, habits, and unique tusks. Here’s what we do know.

1. Narwhals are well adapted to the cold.

Like their cousins, beluga whales, narwhals spend their whole lives in cold Arctic seas. Most are found in the Davis Strait and Baffin Bay area between Canada and Greenland, as well as in the Greenland Sea between Greenland and Svalbard. These medium-size whales have stubby pectoral flippers and lack a dorsal fin, which allows them to swim underneath ice floes and access the surface for air; adults narwhals’ white coloring with gray and black mottling camouflages them among the sea ice.

2. A narwhal’s tusk is actually a tooth.

The narwhal’s scientific name, Monodon monoceros, refers to their singular characteristic and means “one tooth, one horn.” The narwhal’s tusk appears to be situated in the center of its head, but it is really an exaggerated left front tooth that protrudes from the whale’s upper jaw. The right front tooth remains small and inside the mouth. Though narwhals are classified as odontocetes (toothed whales), they literally have only these two teeth in their mouths. Most males sport tusks, but only about 15 percent of females do.

Narwhals feed on rather large fish, such as cod, halibut, squid, and shrimp, but they don’t grab at the prey with their teeth. Instead, they create a vacuum with their mouths and suck in the fish—though this process, often taking place thousands of feet below the ocean’s surface in total darkness, has never been directly observed or filmed. Scientists have witnessed narwhals using their tusks to stun cod before capturing and eating them.

3. The tusks are flexible.

Narwhal tusks (or teeth) are unique in the animal kingdom: they are the only straight tusks and the only teeth known to grow in a spiral. Stranger still, while most teeth (including human teeth) have a hard exterior and a soft, sensitive interior, narwhal teeth are the opposite. “To find a tooth that is soft on the outside and has its most dense part around the pulp was completely odd,” narwhal expert Martin Nweeia, a dental surgeon and lecturer at the Harvard School of Dental Medicine, told NPR after making this discovery in 2005.

Its tough core and soft outer layer result in a tusk that is both strong and flexible. It can bend significantly without breaking, which is important for one as long as the narwhal’s.

4. Narwhal tusks can grow up to 10 feet long.

A narwhal raises his tusk above the ocean's surface
A narwhal raises his tusk. / Doug Allan/Photodisc/Getty Images

Male narwhals average 15 feet in length and weigh 3500 pounds, not including their tusks, which begin protruding from their mouths at age 3 and continue growing throughout the whales’ lives. Tusks measuring 9 or 10 feet are not uncommon. Female narwhals are smaller than males, averaging 13 feet long and 2000 pounds.

5. Scientists have proposed several theories about the tusks’ purpose.

One theory is that the tusk can be used as a weapon (and not just on cod), though this claim lacks sufficient evidence. Another is that it’s an accessory for finding mates and asserting dominance, much like peacock feathers or deer antlers. Nweeia and his team have proposed that it acts as a sensor for picking up environmental cues.

Nweeia’s research has found that the tusk is porous and full of nerves. It may sense external stimuli like water pressure, temperature, and salinity, and send those signals to the brain. To test this theory, Nweeia fitted narwhals with a “tusk jacket” that insulated the tusk from environmental factors. Then, researchers pumped the jacket full of water samples of varying salinity levels to mimic variations in seawater. They found that different levels of salinity caused the narwhals’ heart rates to fluctuate, indicating they could sense the change and had a physical reaction to it. That suggests narwhal tusks are sensory organs that can measure salt concentrations, and perhaps many more conditions in its environment.

However, if the narwhal tusk is a mechanism for sensing the environment, why wouldn’t more females have evolved to have them as well? The lack of tusks among female narwhals seems to support the theory that the tusk is mainly an accessory for garnering attention and establishing dominance among males. Scientists are still looking for the answer.

6. Their name might mean “corpse whale.”

The mottled flukes of a narwhal.
The mottled flukes of a narwhal. / by wildestanimal/Moment/Getty Images

Narwhal is likely derived from the Old Norse nahvalr, combining the words na (“corpse”) and hvalr (“whale”). It may be a reference to the whale’s speckled gray and white skin and its resemblance to dead bodies that had been floating in the ocean for a while. Or, nahvalr may derive from West Norse and mean “whale distinguished by a long narrow projection.”

7. Narwhal skin is packed with vitamin C.

One ounce of narwhal skin contains as much vitamin C as one ounce of an orange—about 15 milligrams. According to a 1930s survey, narwhal skin and eyes were important sources of the vitamin among Inuit in East Greenland, whose traditional diet was primarily meat. The researchers concluded that this foodstuff, along with algae, prevented scurvy among the population.

8. There are no narwhals in captivity.

Unlike beluga whales, narwhals do not thrive in captivity. In the 1960s, the Vancouver Aquarium launched a program to capture or obtain narwhals from the Arctic and display them in the world’s first (and only) permanent exhibit. Eventually, the museum caught or purchased six wild narwhals, which arrived in Vancouver with much fanfare and interest from the public. Unfortunately, all six died months after their arrival. (A young narwhal sent to the New York Aquarium also died within a month). Like great white sharks, narwhals apparently aren’t meant to be tamed.

9. Narwhals were the source of myths and folklore.

Narwhal Beaker by Jan Vermeyen
A 17th-century goblet made from a narwhal tusk. / Francis G. Mayer/GettyImages

In the Middle Ages, the narwhal’s long, straight, pearly-white tusk was thought to be a unicorn horn with the power to purify water and do other kinds of magic. Numerous tusks were given to royalty. In the 16th century, Queen Elizabeth I received one worth £10,000; she also sipped water from a goblet made from a portion of a tusk. English monarchs were known to chip off a bit of the tusk and imbibe it as a therapeutic drink or in a potion believed to prevent poisoning. The Hapsburg rulers had a tusk made into a scepter and adorned with precious gems, but Denmark really went all out: the Danish monarchs’ anointing throne was built in 1660 and incorporated several “unicorn horns” in its design, which were easily sourced from the Danish territories of Iceland and the Faroe Islands.

A version of this story was published in 2014; it has been updated for 2024.

Read More About Underwater Animals: