Monday, February 3, 2014

Mystery Shark

Most people think of sharks as bloodthirsty predators. They are animals capable of sensing blood from miles away, stopping at nothing to hunt their prey, even if said prey is a human, *gasp*. These preconceived notions come largely from Hollywood films like 'Jaws', where the best way to sell tickets is to create an image of a shark so terrifying you want to stay out of the water for the rest of your life. In reality, sharks don't actually destroy fishing boats or tear apart diving cages. There are sharks of all types, and I happened to stumble across one of the more obscure creatures while browsing Twitter

The Greenland Shark is unique. It lives deep in the ocean, over 2,000 meters deep! Water that far down is very cold, and can even dip below freezing. Of course, due to the high pressure at that depth, the water doesn't turn to ice, even though the temperature is below freezing. To prevent the shark's body from freezing in these waters they have adapted to have high levels of trimethylamine oxide in their skin. This chemical helps them deal with the osmotic pressure and the freezing temperatures. It also comes with an added bonus, it is poisonous when consumed. Any predator that takes a bite out of this shark will undergo neurological distress which can be fatal. This is especially useful for the Greenland Shark because they are very slow moving, making them somewhat easy targets. 

If that wasn't weird enough, many of these sharks exhibit a symbiotic relationship with Ommatokoita elongata, a parasite that latches onto and feeds off of the eyes of the shark. But instead of harming the shark (which most people would think is the primary concern when your eyes are being eaten) the sharks can benefit from this parasite. The parasite is slightly luminescent, and attracts fish to the shark. The shark, being used to living 2,000 meters beneath the sea, is well adapted to the dark and can sense the fish using its other senses. 

I hope my brief description of the Greenland Shark has helped to improve people's conceptions of sharks in general. While there are some sharks that aggressively hunt their prey, the Greenland Shark offers a different perspective. I find this to be an important topic because all around the world sharks are hunted for their fins. Many people aren't concerned because they have negative opinions of sharks, but the truth is that these animals are fascinating and deserve to be respected. The more awareness and interest that is displayed towards sharks the more funding will go into studying them and protecting them, so even if you have a mild interest in these animals, let everyone know!

Posted By: Tim Daly (1)


  1. This type of shark sounds different than most we are used to hearing about. I found it interesting that they are actually slow swimmers and can adapt to such cold environments. Even though its poisonous I've heard people actually eat this type of shark,in Iceland, they just have to process it first so it is no longer harmful.
    Posted by Morgan Matuszko

    1. It is true that this shark is consumed by many people. There is a very specific way the shark must be prepared in order to ensure that it is safe to eat. I believe the process involves the repeated freezing and thawing of the meat for several weeks. Because the process takes so long the final product is considered a delicacy!

      Posted by Tim Daly

  2. This was an excellent read! I do have one question though, which concerns with the parasites that feed off the eyes of the shark. Wouldn't that hurt the shark? What about their eyes make them resist the probable pain that comes with the feeding?

    -Posted by Jacob Geier

    1. Good question Jacob. I'm not actually sure about how much pain would be caused by these parasites. The main reason that the sharks can survive seemingly unbothered by the parasites is that the sharks hardly use their eyesight to begin with. The sharks live in almost complete darkness, so maybe they have co-evolved with the parasites in a way that selects for the least damaging parasites and the most hardened sharks?

  3. Awesome take on this. Sharks are often looked down on because of the fact that they come off as vicious predators when in reality cause very little injuries in the grand scheme. Ive never heard of this shark and it was interesting to learn about it, thanks.

    Alex Sroczynski