Recent news has emerged of a Greenland shark to have been aged at over 500 years old. This of course is most likely false, since Henry the VIII could have shared a birthday with the shark. In the same article they state that their estimate ranges over 300 years. Meaning the individual was most likely round the 200 year mark. A known age that Greenland sharks can live past. This shark gets so old that its flesh turns toxic, thus preventing it being eaten by killer whales and other larger species. But its still a delicacy in some parts of the world. Growing up to 20 feet long its the largest shark in the Arctic ocean.

 

An old Greenland shark with copepods attached to its eyes Source – Flickr

Slow Times in the Cold

Living at depths of around 800m and known to go far deeper, in the most northern location a shark habits, The Arctic ocean. Warmth is not something this shark is likely to experience. This ocean consists of temperatures just over zero degrees, the only chance of us surviving in these conditions for 200 years is to be frozen and stumbled upon by the future human race. Pretty unlikely for many reasons. It’s known in biology that metabolic rates are directly affected by temperature, an optimal temperature for every species exists, but not all are similar. The optimal temperature is where the entire metabolic rate of the species is at the most efficient, not just one reaction happening inside the species.

It’s thought that the low temperature and high pressure acts strongly against the Greenland sharks metabolism, thus reducing efficiency. Since the shark is so cold and under high amounts of pressure, more time will be needed to produce the end products of its metabolic reactions in useful quantities, some leading to slow maturity and slow growth, but since everything is slowed down the shark will take time to go through each stage of development leading to a longer life. Another result of having a low optimal temperature which produces low rates, is lack of energy. A direct result of this can be seen in the Greenland shark, being that the shark only moves at speeds of around 0.3 m/s making it the slowest shark known to man. Without the conditions to produce high amounts of energy this shark is set to live a slow chilled life.

A Slow Predator?

The Greenland shark as various adaptation to do with feeding. Although there can be long periods of time where the shark won’t eat, the spine is adapted to be mainly cartilage. Thus requiring less energy to move the tail then when compared to a boney spine. The huge nostrils seen in the above image of the shark are able to smell a drop of blood from over a mile away, this sense is so sensitive due to most Greenland sharks being blind. This is not natural, the sharks are born with vision but a copepod is known to attach to the cornea and eat it, these can be seen in the first image. Since the sharks live so long its likely this will occur. Some of these copepods possess the ability of bioluminescence which leads prey right to the sharks head. Perfect for the slow moving vertebrate. Then with the use of its electro sensory the shark is able to detect prey and feed.

This shark is also fairly smart, by using its nose to detect blood in areas with fast moving prey, it is able to pick out injured individuals that may have little chance of escaping. Meaning the shark can slowly swim to its prey for consumption. Without this smart ability it would take a substantial amount of time for the shark to catch its prey. Luckily theres lights attached to its head signalling prey to come and be eaten.

 

Here you can see an illistration of the wide open jaw a Greenland shark possess. Source – Wikipedia

The shark is also known to simply swim through areas abundant in prey, with its wide jaw located under the body open fully to catch prey. Greenland sharks have been found to contain horses in their stomachs, leading to the thought they will scavenge on dead material since there isn’t many horses in the Arctic ocean.

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