[2] Inhabiting the North Atlantic and Arctic Oceans, they are notable for their exceptional longevity, although they are poorly studied due to the depth and remoteness of their natural habitat.

[4] They are among the largest extant species of shark, reaching a maximum confirmed length of 6.4 m (21 ft) long and weighing over 1,000 kg (2,200 lb).

[6] Greenland shark meat is toxic to mammals due to its high levels of trimethylamine N-oxide,[7] although a treated form of it is eaten in Iceland as a delicacy known as kæstur hákarl.

This does not seem to reduce the life expectancy or predatory ability of Greenland sharks, due to their strong reliance on smell and hearing.

The 48 to 52 lower teeth are interlocking, broad and square in shape, containing short, smooth cusps that point outward.

[21] Small Greenland sharks eat predominantly squid, as well as sea birds, crabs, amphipods, marine snails, brittle stars, sea urchins, and jellyfish, while the larger sharks that are greater than 200 cm (79 in) were discovered eating prey such as epibenthic and benthic fishes, as well as seals and small cetaceans such as oceanic dolphins and porpoises.

[27] Although such a large shark could easily consume a human swimmer, the frigid waters it typically inhabits make the likelihood of attacks on people very low.

Around 1859 in Pond Inlet, Canada, it was reported that a Greenland shark was caught containing a human leg in its stomach.

During the winter, the sharks congregate in the shallows (up to 80° north) for warmth but migrate separately in summer to the deeps or even farther south.

The species has been observed at a depth of 2,200 metres (7,200 ft) by a submersible investigating the wreck of the SS Central America that lies about 160 nautical miles (180 mi; 300 km) east of Cape Hatteras, North Carolina.

[34] In August 2013, researchers from Florida State University caught a Greenland shark in the Gulf of Mexico at a depth of 1,749 m (5,738 ft), where the water temperature was 4.1 °C (39.4 °F).

The discovery indicates that Greenland sharks may have a wider distribution in the tropics, primarily at greater depths, than previously believed.

And, if we are to believe Crantz, this motion is to be observed three days after, if the part is trod on or struck.The Greenland shark has the longest known lifespan of all vertebrate species.

[15] Like other elasmobranchii, Greenland sharks have high concentrations of the two nitrogenous compounds urea and trimethylamine N-oxide (TMAO) in their tissues, which increase their buoyancy[47] and function as osmoprotectants.

These three types show very similar oxygenation and carbonylation properties, which are unaffected by urea, an important compound in marine elasmobranchii physiology.

[56] The rate of projected loss of sea ice will continue to negatively influence the abundance, distribution and availability of prey, while, at the same time, providing greater access for fishing fleets.

[56] There is greater potential for new fisheries to develop as more productive and abundant southerly species invade the warming Arctic waters.

They have a slow growth rate, late maturity period, and low fecundity, making the management and conservation of this species very important.

Therefore, Greenland sharks' longevity and conservative life history traits, in tandem with their vulnerability to accidental catching and commercial fishing, promotes a growing concern for the sustainability of this species.

[56] The flesh of the Greenland shark is toxic because of the presence of high concentrations of urea and trimethylamine oxide (TMAO).

[62] The legend says that an old woman washed her hair in urine (a common practice to kill head lice) and dried it with a cloth.

Igloolik Inuit believe that the shark lives within the urine pot of Sedna, goddess of the sea, and consequently, its flesh has a urine-like smell and acts as a helping spirit to shamans.