10 narwhal facts: tusks, diet, habitat, and more
Though narwhals are one of the least common whale species we see during our expedition cruises, a trip to the Arctic (specifically Greenland and Svalbard) always offers us the possibility of encountering these elusive whales.
The name “narwhal” comes from Old Norse: nár means “corpse” and refers to the whale's mottled gray appearance, which was thought to resemble the pallor of drowned sailors. In Inuit, however, the narwhal is called qilalugaq qernertag, meaning “one that is good at curving itself toward the sky.” This name refers to the narwhal habit of curving its back downward when diving, then curving its head upward when lying on its back, pointing its tusk to the sky. Meanwhile, the narwhal's scientific name, Monodon monoceros, translates to “one-tooth one-horn,” which is accurate for reasons we'll discuss later.
Like the beluga whales to whom they are related, narwhals seldom appear during our cruises - which makes seeing them all the more special. So if you decide to embark on an Arctic cruise, keep the following narwhal facts in mind should you be lucky enough to spot this beloved aquatic unicorn.
1. Narwhals are rare to see but easy to spot
We might rarely encounter narwhals, but when we do they're not hard to identify. Narwhals have small rounded heads and short flippers with upturned tips. Males are larger than females, with the largest of the species reaching around five meters (16 feet) long. Their skin color changes with age, which we will explain below. Newborn narwhals, juveniles, adults, and old narwhals are all distinctly colored. Narwhals live between 30 – 40 years, and their chief predators are orcas (killer whales).
2. You can determine a narwhal’s age by its color
If you spot a narwhal during your Arctic trip, you will be able to make a relatively educated guess about its age simply by looking at the color of its skin. Newborn narwhals are blue-gray, but they turn blue-black as they advance into their juvenile years. Adult narwhals have spotted gray skin, and older narwhals become almost completely white.
3. Suction feeding is the narwhal way
Some people think the narwhal uses its tusk as a way to spear or snare food, but this is not the case. The narwhal is a suction feeder, like most whales, swallowing its food whole. Narwhals live primarily on squid, rockfish, Greenland halibut, shrimp, crab, polar cod, flounder, and Arctic cod.
4. Narwhals are closely related to beluga whales
As mentioned above, the beluga is a relative of the narwhal - the closest relative, in fact, and they have adapted similarly for the harsh Arctic conditions. Narwhals and belugas do not have dorsal fins, which makes it possible for them to break through thin patches of sea ice to breathe. In some cases, narwhals and belugas have even bred together, leading to at least one documented beluga-narwhal hybrid.
5. Sonar is a narwhal specialty
A narwhal's tusk enables it to see like few other animals on Earth, giving it some of the most precise sonar ever recorded. Narwhals make clicking sounds (up to 1,000 per second), using the echoes to reconstruct their surroundings in the water. The narwhal tusk, sensitive to even the slightest stimuli, is thought to further aid echolocation by letting sea water in through pores in the tusk’s tip. Sound waves travel through the tusk, touch nerve endings at the base, and produce signals in the narwhal's brain that help it determine its surroundings.
6. Narwhals prefer pack ice
Like all whales, narwhals have to regularly return to the surface of the sea to breathe. But because narwhals live predominantly below the pack ice, they have to be well accustomed to utilizing the few areas of open water available to them during the Arctic winter. This is impressive when you consider that only about five percent of the Arctic pack ice might have sufficient breathing holes between February and April.
7. Diving deep is no problem for narwhals
In summer, narwhals typically dive to depths between 30 and 300 meters (100 – 1,000 feet), but the majority of the time they live between the surface and 50 meters (165 feet) of it. During the autumn, narwhal dive depths and durations increase when migrating to their wintering grounds. At these wintering grounds, narwhals stay in a limited area for about six months and make small movements with the cracking of the pack ice.
Narwhals take some of the deepest dives known for a marine mammal at this time: up to 800 meters (2,600 feet), sometimes even 1,500 meters (4,900 feet). Over this winter period, narwhals dive to these depths around 18 – 25 times per day. The duration of these deep dives is around 25 minutes. At these depths, the conditions are life threatening, as pressure exceeds 2,200 PSI in the pitch-black water.
8. Narwhals are natives of the far north
In case it's not already clear, narwhals are a distinctly northern species. We do not see them in Antarctica, the Falklands, South Georgia, or any other region of the Southern Hemisphere. And while we only encounter narwhals in eastern Greenland and around Svalbard during our summer voyages, scientists have found winter home ranges for narwhals in Baffin Bay and many other areas around the globe.
9. Deep water adaptations aid the narwhal
Due to some key adaptations, narwhals can survive at truly staggering depths. They have a flexible rib cage, enabling their bodies to be highly compressed. Once their rib cage compresses, their lungs “collapse,” and the air inside is channelled into their trachea system. Narwhals also have a high concentration of myoglobin, twice as much as some seals and eight times as much as terrestrial mammals. In fact, the typical narwhal can carry 70 liters, or 18.5 gallons, of oxygen in its lungs, blood, and muscles.
Additionally, narwhals have muscles designed for endurance swimming, demanding less oxygen than species like dolphins, which have fast-twitch muscle fibers. Narwhals also have streamlined bodies, enabling them to glide effortlessly through the water. Furthermore, narwhals exhale before dives, limiting the gas exchange in their blood. This also limits the chance of decompression sickness.
10. The narwhal tusk is actually a tooth
Perhaps the most discussed (and definitely the most distinguishable) narwhal feature is its tusk, which is actually not a tusk at all. If our verbiage in previous paragraphs misled you, allow us to set the record straight: The long ivory protrusion spiraling counter-clockwise out of a narwhal's head is actually a large canine tooth. Some male narwhals have two of them, while only 15 percent of females have this tooth at all.