The weirdest shark in the world

Greenland sharks are the slowest shark that humans have ever known, with a domestic movement speed of only 1.6 km / hour.

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The study, published recently in the September issue of Biology of the Sea, also shows that, even when swimming at full speed, Greenland sharks can only reach a maximum speed of 2.7km.

Greenland sharks are the slowest swimmer of all sharks and fish in general.

The explanation for this peculiarity, said Yuuki Watanabe, a researcher at the National Polar Research Institute, that it is the low temperature of the Arctic Ocean that causes Greenland sharks to be so slow.

Watanabe and colleagues used metering devices to determine the speed of swimming and the tail-swing frequency of 6 Greenland sharks, then compared with other shark and general fish species.

The results showed that both the tail-thrust frequency and the maximum recorded speed of Greenland sharks were the lowest in the table, especially considering the size of the fish.

Because of the slow swimming speed, the hunting methods of Greenland sharks are also different. Many killer sharks can swim like electricity in the water, allowing them to easily attack underwater fish and mammals. But when the gastric surgery of Greenland shark, many young fish were found and the fresh seal was not decomposed.

How is 'Greenland shark hunting seals still a mystery' , Watanabe said. And although very slow, Greenland sharks still have not many enemies thanks to its massive body size. Some individuals can be up to 6.5 meters long and weigh up to 997kg. Killer whales can eat Greenland sharks, Watanabe assumes, but Greenland sharks often live in deep waters where killer whales rarely hover.