During my first year of university one of my tasks was to write a series of short blogs. Whilst trying to organise the mess that is currently my desktop, I found one of my favourite and thought I’d share…
It wasn’t until I watched Elf one Christmas (a fair few years ago might I add) that I was aware of the existence of Narwhals Monodon monoceros. As Buddy bid farewell to his friends at the North Pole, a huge unicorn like tusk twist its way out of the water. In reality this does not belong to a mythical creature, but a whale, aptly known as the Artic Unicorn or more commonly, the Narwhal. They are truly remarkable creatures and the memory of this film inspired me to research more into their secretive and illusive behaviour.
Narwhals inhabit Artic waters on Canadian and Greenland borders, congregating here in the summer in fjords and bays. They begin their epic 600 mile journey by navigating their way through the ice, all the while travelling North in search for richer fishing grounds.
They are considered ‘Marathon runners’ of the ocean and are able to be so due to the composition of their muscles. Narwhal swimming muscles’ are composed of 87% slow twitch fibres, which is considerably higher than that of other marine species. Dolphins, for example, require fast twitch fibres, enabling them to move efficiently at high speeds in short bursts. Slow twitch fibres of the Narwhal respond slowly but do not tire easily.
Slow-twitch fibres are adapted to do this by having a good blood supply from a complex capillary network, giving them the name ‘red fibres’. They also have large amounts of myoglobin, an oxygen store. It is the high levels of myoglobin that allows Narwhal to be exceptional divers. Myoglobin is similar to haemoglobin, except it only has one polypeptide chain and a single haem group. It associates readily with oxygen to form oxymyoglobin, it then only dissociates at very low partial pressures of oxygen. This is particularly useful when the partial pressure of oxygen in muscles becomes very low after strenuous exercise, a dive in the case of the Narwhal.
Despite this, it is important that they are aware of breathing holes in the ice and these can be detected using their unicorn like tusk. The tusk is in fact a spiral tooth which can grow to lengths of up to 8 feet and emerges from the left side of the upper jaw. It is thought that it contains hydrodynamic sensor capabilities with around ten million neurones running from the central nerve of the tusk to the outer interface. The outer surface is extremely sensitive and is capable of detecting changes in water temperature, pressure and particle gradients. Detecting particle gradients allows them to determine the salinity of the water, aiding their survival.
Tracking and successfully spotting Narwhals is considered a spectacular yet rare event, however satellite tracking has provided information on the movement of these magnificent mammals. With this new technology we can discover new behaviour such as diet and movement which will aid in the survival of this near threatened species.