K's Kreature Feature is an educational presentation at our monthly general staff meetings here at the Two Oceans Aquarium, but it’s only right that we extend the knowledge and fun to our readers here on our website. Every month Education Operations Co-ordinator Katja Laingui presents a different animal that we have here at the Aquarium and tells our colleagues more about it. Usually she uncovers some rather interesting facts about the various animals she researches. She also makes sure to entertain her co-workers…

Before you get too excited, we do not have a Greenland shark at the Two Oceans Aquarium, but if we did, how awesome would that be?

The reasons we do not have one are the following: as the name suggests, they live in cold Arctic waters, such as those around Greenland, and they are absolutely massive. We simply do not have the space to keep such a large animal and feeding it would become troublesome, but more about that later.  

This 3.8m giant is only a sub-adult! Upon dissection, the remains of a polar bear were found in her stomach. Image source: @juniel85

The Greenland shark is also known as the gurry shark or the grey shark. It also has an Inuit name, since it plays an important role in the Inuit culture. They call the Greenland shark "Eqalussuaq". In terms of its taxonomic name, Somniosus microcephalus, the genus name Somniosus means "to sleep". The Greenland shark actually belongs to a group of sharks called the "sleeper sharks", which all have similar characteristics. The species name, microcephalus, is directly translatable to "small head". Considering that the Greenland shark is one of the largest shark species around, growing up to 6.4m, the ‘small head’ possibly refers to a small brain, relative to body size.  

I like to talk about the people behind the names of the animals I research. And by people I mean men, since there weren’t many female scientists back then. The Greenland shark was described by two people: Marcus Elieser Bloch and Johann Gottlob Theaenus Schneider.

The remarkable thing about Marcus Bloch was that he was illiterate until the age of 19. He ended up learning to read and write German and Latin. He became a medical doctor and has been heralded as one of the most important ichthyologists (a fish scientist) of the 18th Century. He described a total of 176 species of fish.

Johann Schneider, also a German like Bloch, was a naturalist and classicist. He wrote a Greek-German dictionary, which has been used as a basis for more recent works. He also re-worked and expanded Bloch’s Systema Ichtiyologiae iconibus cx illustratum, Bloch’s major piece of literary work. A cool qualification that Schneider had was Professor of Ancient Languages and Eloquence.

The Greenland shark has a wider distribution than its name suggests.

This Greenland shark was found with discarded nylon cord, cutting 2cm into its flesh. Poor guy! Glad these researchers found him. Image source: @juniel85

Interestingly you can find this shark along the cold-current coastlines of France and Portugal as well as on the other side of the Atlantic along the coast of Canada.

This small bycatch Greenland shark is less than 50 years old. It is the only one ever seen to have white spots. Image source: @juniel85

They are also found in the waters of Iceland and have a traditional significance there in the form of hàkarl, which is the national dish. Hàkarl is fermented Greenland shark. The process of making this dish is rather extensive, mainly because eating raw Greenland shark is toxic to most beings.

Hàkarl drying process.  

The tissues of this shark are full of urea and trimethylamine N-oxide (or TMAO for short). The TMAO actually acts as a natural anti-freeze, which allows the shark to live in cold temperatures, from -1 to 10 °C, but it has some unpleasant side effects if consumed. Because of this, the meat of a Greenland shark has to undergo a fermentation process. The cleaned carcass is buried with stones and other weights pressed onto it so that the fluids are pressed out. It will stay in this "grave" for six to 12 weeks. The meat is then hung to dry for another few months and only then is it considered safe to eat.

A giant Greenland shark, waking up after a tag-and-release programme. Image source: @juniel85

There are more modern techniques now, which no longer involve the burying of the carcass. However, one wonders why the Icelandic people go through all of this effort, as the dish apparently tastes absolutely awful. Chef Gordon Ramsay challenged James May (from Top Gear) to eat three different "delicacies" on his show The F Word - snake whiskey, bull penis and hàkarl. Here is that section of the episode; a fair warning though, it is Gordon Ramsay, so expect swearing.

Apart from being poisonous, the Greenland shark has other physiological peculiarities. It has an extremely slow metabolism, due to living in such cold environments. This has allowed the shark to be extremely long-lived. One specimen is believed to be 400 years old. That is a long time!

Not all Greenland sharks are giants - these little ones are closer to the average. Image source: @juniel85

This shark was around when the Taj Mahal was built in 1643; when Napoleon took over Europe in 1796; when Haiti was the first black nation to become independent from colonial rule in 1804; when women were allowed to vote in New Zealand in 1893; two world wars in the 20th Century; and when that volcano (Eyjafjalljökull ) that nobody can pronounce, except for Icelandic people, erupted in 2010. This shark has been through a lot. 

Image source: @juniel85

They can also dive down to 2 200 metres and are called the "sloths of the ocean" since they are so slow. You might wonder what these giant sloths eat to get so big. Well, pretty much anything. They eat normal sharky stuff, like fish and seals and sometimes dead things they find on the ocean floor. But some Greenland sharks have been caught with reindeer in their stomachs. A whole reindeer. Some also opportunistically hunt sheep that are too close to the water’s edge as well as man’s best friend, the dog. There are also reports of horses disappearing and one Greenland shark was found with polar bear remnants in its stomach. So anything goes, says the Greenland shark.

Greenland sharks' unique teeth act as knives and forks, enabling them to chew up large carcasses. Big ones like this can swallow a seal whole. Image source: @juniel85

Another interesting feature of this animal is that it is never alone, in the cold, dark depths of the ocean. It is said that up to 90% of these sharks have a BFF (Best Friend Forever) attached to their eye (or both) for their whole lives. This creature is a copepod (shrimp-like animal) called Ommatokoita elongata. It burrows into the eye of the Greenland shark and pretty much renders it blind. Luckily the shark can still distinguish between light and dark, but technically the shark doesn’t need to see much anyway in the depths that it lives in, so it is a win-win situation.

To get over the fact that the Greenland shark has to swim around with another animal burrowed into its eye, here is a peaceful video of one Greenland shark swimming around, without a worry in the world.

We may not have a Greenland shark at the Aquarium, but we have our fair share of gentle giants - Yoshi the loggerhead sea turtle and our fintastic shiver of ragged-tooth sharks to name a few. Or perhaps you're more interested in meeting the Greenland shark's cutest little cousin...

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