The animals who inspired the unicorn legend exist in real life, and they are completely fascinating.

Known fondly throughout the world as the “unicorn of the sea,” the remarkable narwhal is just as unique as it is elusive. Its most defining trait, the long tusk that spirals counterclockwise from its upper lip, has helped earn the narwhal its rightful place among history’s legendary sea creatures.

Along with beluga whales, the narwhal is one of just two species included in the cetacean family monodontidae. These fascinating whales do not migrate, spending all of their lives in cold Arctic waters throughout Canada, Greenland, Norway, and Russia.

From the mysterious purpose of their protruding tusks to the way they survive entire months under sea ice, discover what helps make the narwhal one of the planet’s most mysterious marine mammals.

1. Narwhal Tusks Are Actually Teeth

A narwhal’s tusk, which can grow up to 2.6 meters (8.53 feet) in length, is really a massive canine tooth that grows out of its upper lip in a spiral pattern. Narwhals technically have two tusks, one on the left and another on the right, though it is typically the left side that protrudes fully from the lip. 

Only recently was it discovered that narwhal tusks also have sensory abilities. In 2014, scientists from Harvard Medical School found that a narwhal's heart rate increases and decreases when the tusk is exposed to high or low salt concentrations in ocean water.1

2. They Are Not Endangered

According to the IUCN Red List of Endangered Species, global narwhal populations number around 123,000 mature individuals.2 Currently listed as “Least Concern,” the narwhal is distributed throughout northeastern Canada, Greenland, and northern Russia as far as the East Siberian Sea. There are believed to be 12 subpopulations of narwhals, with 10 that number over 10,000 and two with less than 35,000.

3. Narwhals Are Deep Divers

During the winter months, narwhals are routinely reported to engage in some of the deepest dives among ocean mammals. They dive multiple times a day, preferring deeper areas in Arctic fjords and the continental slope, where depths range from 1,600 feet to almost 5,000 feet. Greenland narwhals are also known to visit deep areas, and biologists have recorded daily dives exceeding 3,000 feet.3

4. Their Diets Consist of Fish, Squid, and Shrimp

Narwhals have a limited variety of prey available to them, doing most of their feeding where open water meets sea ice attached to the shoreline. Their favorites are Greenland halibut, polar and Arctic cod, shrimp, and Gonatus squid.

Since they use their diving skills to catch most of their food in the frigid, dark waters of the Arctic, researchers have limited knowledge about their feeding techniques. The first study of narwhal winter feeding habits didn’t even occur until 2006, when scientists discovered that narwhals have access to an extremely restricted diet across all seasons.4 In the fall, Gonatus squid was the only prey item observed in the stomachs of 121 narwhals.

5. Narwhals Spend Entire Months Under Sea Ice

Most of the narwhal’s mystery stems from the fact that they are so difficult to study. The timid animals live in some of the most remote places on Earth in habitats that are dark and covered in ice for most of the year. The narwhals of Baffin Bay have less than 3% access to open water between the months of January and April, with a minimum of 0.5% open water by the end of March.5 They are able to survive by finding small cracks in the ice to take the occasional breath while remaining hidden.

6. The Purpose Behind Their Tusks Is Still Up for Debate

Scientists continue to disagree on why narwhals evolved to have such a unique feature. Hypotheses range from spearing fish and breaking ice to the theory that tusks create a built-in environmental sensor for feeding.

Recent studies, however, point toward tusks as a means to compete for and attract mates. In 2020, researchers collected biological data on 245 adult male narwhals over the course of 35 years, measuring growth and variation in tusk length.6 The study found that the largest males had longer tusks, suggesting that males with longer tusks are more likely to reproduce.

7. Not All Narwhals Have Tusks

Male narwhals are more likely to have tusks, and only about 15% of female narwhals do.7 The fact that a majority of narwhals with tusks are male is further proof to the theory that tusks are used to compete while mating. There have even been a few rare narwhals observed with two extending tusks, some of which are on display at the Sant Ocean Hall in the Smithsonian National Museum of Natural History.

8. They Are Especially Threatened by Climate Change

Like most arctic predators, narwhals rely heavily on sea ice for survival. They use it to hide from predators like killer whales and feed on prey. Rising sea temperatures have been connected to smaller populations of narwhals in Mideast and Southeast Greenland. In spots where the summer sea temperatures were highest (43 F), narwhal abundance was smallest (less than 2,000 individuals)8 compared to colder waters (33 F), which had the largest narwhal populations (over 40,000 individuals).

9. They Change Color as They Age

Narwhals are white or light gray when they are born and reach a bluish black color when they become juveniles. As they continue to age, their skin coloration becomes darker and more mottled, only to lighten again in old age (older narwhals are almost completely white). This color change comes in handy to researchers, who use the color variants to identify and study baby narwhals in the wild.9

10. Narwhals Can Live a Long Time

Narwhals are believed to be one of the longest living marine mammals, with an average lifespan of 50 years, despite spending their lives in one of the most dangerous environmental conditions on Earth. To prove it, researchers in 2007 measured changes in eye chemistry to determine the ages of 75 deceased narwhals found in Greenland between 1993 and 2004.10 They determined that 20% of the whales were older than 50 years, while the oldest was a female estimated to be between 105 and 125 years old.

11. People Really Used to Believe That Narwhal Tusks Were Unicorn Horns

Back in the 1500s, narwhal tusks were collected and sold as “unicorn horns'' to the wealthy, as they were believed to neutralize poison. Even Mary Queen of Scotts had a personal piece of tusk to help protect her from Queen Elizabeth I. 

Unicorn horns were also thought to ward off disease, so they were often used in jewelry as well. The Imperial Crown Jewels of Austria were made up of a scepter fashioned from a narwhal's tusk surrounded by rubies, sapphires, and pearls, while the Danish Royal Throne used for coronations between 1671 and 1840 was constructed out of ivory and narwhal tusks.11

12. There Are No Narwhals in Captivity

Unlike their beluga cousins, narwhals have never been successfully kept in captivity. For a brief period in the 1960s and 1970s, there were several attempts to capture and keep some of these elusive whales in aquariums and zoos, all of which resulted in the animal’s tragic death. 

In 1970, the New York Aquarium at Coney Island had the only narwhal exhibited at a public aquarium. The narwhal, named Umiak, lived in captivity for just a few days before succumbing to pneumonia.