The Greenland shark (Somniosus microcephalus), also known as the gurry shark, or grey shark, or by the Inuit name eqalussuaq, is a large shark of the family Somniosidae ("sleeper sharks") native to the waters of the North Atlantic Ocean around Canada, Greenland, Norway, and Iceland. These sharks live farther north than any other shark species. Many of the species' adaptations are due to it being the only truly sub-Arctic species of shark. They are closely related to the Pacific sleeper shark. The species has the most toxic meat of any shark.