A few weeks ago I watched a YouTube video about greenland sharks on the Real Science channel. I'd neve even heard about this kind of sharks and I was very surprised by the way of living and lifespan of this animals.

Greenland sharks live in below freezing deep waters but can also come up to the surface. They swim very slowly and are basically blind due to a type of parasite that attaches to their eyeballs - almost every individual have at least one of these parasites. The parasites are spaghetti-like worms that dangle from the shark's eyes as it swims - it's pretty disturbing.

One of the most impressive aspects of these sharks are their lifespan. Scientists don't have a precise number, but it's estimated - through carbon dating of eye cells from living specimens - that the greenland sharks can live up to almost 500 years (carbon dating is not very precise, so the sharks studied could be between 270 and 500 years old).