Narwhal
A group of male narwhals surfacing in the arctic circle. (Source)

Narwhals (Monodon monoceros) are a species of whale found in Arctic waters (Canada, Greenland and Russia) all year round. The name Monodon monoceros means “one tooth one horn” however their mouth contains no teeth, their tusk/horn (only found in males) is a spiralled tooth that protrudes from the upper jaw and can be between 2-3 metres long. They are carnivorous whales that feed on Arctic cod (Arctogadus glacialis) during the summer and predominantly flatfish in the winter. Narwhals are commonly found at a depth of 50 metres but they are capable of diving up to 300 metres to feed during the summer. Though there is not much known about the narwhal, they have been greatly discussed for centuries by biologists and sailors, leading to many myths being written and artists depictions of them.

Mythology

The narwhal has been the centre of a few tales of myth from the 19th century, cementing itself as a cultural figure to sailors and the Inuit people that inhabit the arctic regions of Canada, Russia and Greenland. The Inuits believed that the narwhal originated from a boy who managed to convince his mother to tie a harpoon around her waist and then threw her into the ocean. The harpoon hit a whale and it and the whale merged with the woman’s hair forming the tusk.

Ancient depiction of narwhals (source)
Ancient depiction of narwhals (source)

Narwhals are also believed to be the origin of the unicorn. This could be due to many fishermen capturing the narwhals by mistake or as by-catch. They would cut off their tusks and take it back to give to the family or sell to the public with either a lack of description of where the tusk came from, or with legend of unicorns in faraway lands, as sailors used to tell lots of over exaggerated stories of their fishing ventures.

 

How have narwhals adapted to these extreme cold conditions found in the arctic circle?

Just like most other whales narwhals posses thick layers of blubber under their skin which acts as a form of insulation from the cold temperatures. The average weights for narwhals are 900 kg for females and 1,600kg for males, and one third of this weight is blubber. This blubber is often consumed by the Inuits and the Chuckchi, in a form known as “muktuk” an important source of vitamins C and D.

Narwhal Muktuk. The fatty blubber can be seen clearly, showing the way narwhals insulate themselves. (source)
Narwhal Muktuk. The fatty blubber can be seen clearly, showing the way narwhals insulate themselves. (source)

Another form of adaptation seen, is their greyish skin colouring, which is a good form of camouflage next to underwater sea ice, making it very hard to be seen by potential predators, it is said to represent a drowned body due to the “lifeless” grey colour.

When it comes to surviving throughout the seasons narwhals use migration in order to ensure they are able to feed all year round, they communicate with their group in order to find rich areas of food, to survive the harsh winter conditions found in the arctic circle. Their necks are flexible allowing their field of view to be much greater than that of other marine animals, this makes searching for food much more efficient when they are feeding on flatfish on the seabed. When submersed they are able to hold their breath for up to 25 minutes, allowing them to dive down to 300m. Narwhals only feed on the flatfish during the summer as they tend to be obstructed by masses of sea ice during the winter, this is when they typically migrate south whilst remaining in the arctic circle to feed on the arctic cod in the water column away from the sea bed.  Narwhals are able to preserve their oxygen usage due to their very finetuned muscles that are specifically designed for endurance swimming and cutting off blood flow to non-major organs and body parts.

Finally, the most unique part of the narwhal that fetches the most attention is the tusk, however very little has been discovered in the actual function of it, and why it is a prominent appendage. There are a few theories of what the tusk is used for and although none have been proven, they are assumed to serve the functions mentioned:

A close up of a narwhals tusk, the twisting structure can clearly be seen as can the hole in which in comes out of the head.
A close up of a narwhals tusk, the twisting structure can clearly be seen as can the hole in which in comes out of the head. (source)

They could be used as a form of sensory organ, upon inspection of these tusks there have been nerves and tissues found that could be used for reacting to salinity of the water, this could be to allow the narwhal to determine if the water is likely to freeze in a relatively short amount of time.

They are also believed to be used for digging and creating holes. This could be used when searching for flatfish, using their tusk as a method of disturbance on the seafloor to alarm the flatfish making them lose their camouflage and cause them to move into the water column for an easier catch. They also could be used for breaking sea ice allowing them to reach the surface to breath if their resurface is blocked or they become trapped under ice.

Finally, is the theory of hierarchy, just like stags the horn could be used as a sign of male dominance and used for fighting other males in order to compete over mates. This is one of the most believed theories. However, there have been no witnessing of these fights or demonstrations of any aggressive behaviour in general.

The tusks are not an integral part and appear to not be needed for survival as they are not present in females who tend to live much longer even though they inhabit the exact same areas.

The main cause of death is suffocation and drowning when they become trapped under sea ice, meaning knowledge about using their tusks to make holes is insufficient as it is unknown if they are able to break the sea ice or if the death is caused due to the ice being too thick.

More research is needed to fully understand these creatures and the roles they have on our planet and in order to determine the true function of the world’s most unique tooth.

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