The narwhal (Monodon monoceros) is a medium sized toothed whale that’s only found in Arctic waters. As it lives in remote places, in a habitat that’s dark for half the year and covered in ice, the narwhal is not easy to access in order to study. This means there’s still a lot we have to learn about this cetacean.

Narwhals are best known for the unusual tusk that comes out of their heads, giving them the name ‘unicorns of the sea’ and lending them an often mythical status (Inuits in Greenland call them by a name which means “the one that points to the sky”).  

They’ve adapted to become one of the deepest diving marine mammals, capable of diving to depths of more than 1,800 metres and spending lengthy periods of time below 800 metres, a feat not many marine creatures can sustain.  

Born as blue-grey, narwhals change colour during their lives – to black-blue as juveniles and then to a mottled grey colour as adults. And finally to a white colour as they reach old age.  

They have a robust (some would call it sausage-shaped!) body with a small bulbous head and little to no beak. They have short flippers and don’t have a dorsal fin (they do have a ridge on their back though). Even though they are toothed whales, people say narwhals sometimes look more like dolphins or porpoises, save for the tusk on their head and their bigger size.  

The narwhal’s colouration contributed to its name, which comes from the old Norse language. The prefix ‘nar’ means ‘corpse’ and ‘hval’ means whale. The name ‘corpse whale’ refers to how its skin colour resembles that of a drowned sailor.  

Length-wise, a narwhal generally measures anywhere between 4 and 5.5 metres and it weighs in at 1.5 to 1.9 tonnes. The species has a single blow hole, which is typical of toothed whales. We know that narwhals live to at least 25 years of age and can live up to 50.  

What’s commonly referred to as the tusk on its head is actually an enlarged tooth with millions of nerve endings inside it. This tusk is most commonly found on males (only three per cent of females grow one and they’re not as prominent as the males’ tusks). Some whales actually have two tusks.  

The tusk is spiralled to the left and can grow up to three metres long. It had been thought that the tusk helps males with their dominance but new drone footage from 2017 in Canada revealed narwhals stunning fish with their tusks before eating them.  

Take a look at the clip below:  

Where do narwhals live? 

Narwhals are year-round inhabitants of the Arctic Ocean and are spotted in Canada, Greenland, Alaska, Norway and Russia.  

The majority of the world’s population spend the winter under the sea ice in the Baffin Bay – Davis Strait area (which is between Canada and western Greenland). This area is also a habitat for bowhead whales, belugas, fish and seabirds.   

While they live all year in the Arctic Circle, they do move around – to ensure they don’t get trapped by pack ice at the height of winter, and to spend time in coastal waters and fjords in the summer.  

Narwhals travel in groups, usually between 15 to 20 individuals although larger gatherings of hundreds have been observed.  

When they travel together, the whales swim fast and close to the surface. Sometimes they float together motionless at the top of the ocean or they leap out of the water and then dive underneath in unison. 


The species is difficult to study, meaning population figures are very firmly estimates. It’s thought that there around 80,000 narwhals though other reports estimate there are 120,000.  

The species was last assessed in 2017 for the IUCN Red List of Threatened Species and was deemed to have ‘Least concern’ conservation status 

However, there are concerns about their population levels in specific regions (see ‘Threats to narwhals’ section below).  

What do they eat? 

Narwhals dive down deep to get their food, often to the bottom of the ocean. They’ve been known to dive to as deep as 1,800 metres and stay down there for 30 minutes. They feed intensely during the winter period and eat very little during the summer season.  

Their primary prey includes halibut, shrimp, cod, squid and crab (when they find them on the seabed). They’ve an unusual way of eating – first finding their food through echolocation and then creating a kind of vacuum with their mouth to suck them up. As mentioned, researchers have observed narwhals using their tusks to stun their prey before eating them.  


Threats to narwhals 

Climate change/pollution 

As their life cycle and habitat is so closely connected to life in the Arctic Circle, narwhals are thought to be the whale species most affected globally by climate change and the melting of the polar caps.  

Interestingly, a study in October 2022 shows that narwhals are adapting to the climate crisis by delaying migration. It’s positive that they’ve developed an ability to adapt to the changing Arctic environment but unfortunately this change in their behaviour also involves an increased risk of becoming trapped under ice and drowning. 

A 2021 study of narwhal tusks showed that in the past 20 years, the amount of mercury found in them has increased significantly, without a simultaneous shift in the species’ diet.  

The researchers from McGill University in Canada attributed this rise to on-going fossil fuel combustion in South-East Asia and said it could also be due to changing sea ice conditions as the climate warms and changes the environmental mercury cycle in the Arctic.  

Oil and gas development in this region also poses a threat to the species, with more opportunities for collisions and for increased noise pollution disturbing the narwhal’s normal behaviour.  

Natural predators

The narwhal has few natural predators, due to its large size and its habitat in a remote location. One of its predators is the orca 

Less often, polar bears and walruses have been observed killing narwhals that have become trapped in shallow pools of water near ice, unable to move away. 


Inuit people have hunted narwhal for centuries for their flesh, blubber and tusks.  

In 2004, Greenland’s government introduced, for the first time, quotas for hunting narwhal and banned the exportation of their tusks. Despite this, the population in east Greenland is still of major concern to the Greenland Institute of Natural Resources (a government advisory body that monitors the environment.  

It has warned that narwhals are at high risk of extinction in this region and in 2021, it advised a ban on hunting in three key areas. You can read more in this news article in The Guardian which also explores the tensions between hunters and scientists in the East Greenland region.