The Somniosidae family. Another group of shark found in the deep sea are the sleeper sharks, so named because basically they move really slowly. These bizarre creatures are possibly the world's saddest shark. Unusually for sharks, sleepers can live in polar regions. The Pacific and Greenland shark can be found in Arctic waters while the Southern sleeper shark is found in the Antarctic. This means they have to contend with the much colder temperatures of these waters as well as the deep sea. In fact their main issue is flat out freezing. Their livers, which keep them buoyant, contain different molecules to stop them from freezing solid in the colder temperatures as well maintain the function of their muscles and digestive systems. Because of their super-slow metabolism, they are thought to live incredibly long lives - somewhere in the region of 200 years. They spend most of this alone, apart from the tiny parasites that have evolved to latch onto their eyes and eat their corneas. What a life. They are still highly successful predators however. They are known to hunt fish, crabs, sea birds (when near the surface), other sharks, seals, whales and even giant squid (which, *spoiler alert*, well get to later). Their choice of prey appears to be decided mainly on whats available. A jack of all trades they may be, but in nature thats often the best strategy for survival. Oh, and their flesh is toxic as part of its not-freezing-solid system. Definitely an alien.
