in summer to the deeps or even farther south. The species has been observed at a depth of by a submersible investigating the wreck of the SS Central America that lies about east of Cape Hatteras, North Carolina. Daily vertical migration between shallower and deeper waters has also been recorded. In August 2013, researchers from Florida State University caught a Greenland shark in the Gulf of Mexico at a depth of , where the water temperature was . Four previous records of Greenland shark were reported from Cuba and the northern Gulf of Mexico. A more typical depth range is , with the species often occurring in relatively shallow waters in the far north and deeper in the southern part of its range. In April 2022, a large Somniosus shark was caught and subsequently released on Glover's Reef off the coast of Belize. This shark was identified as being either a Greenland shark or a Greenland/Pacific sleeper shark hybrid. This observation is notable for being the first possible record of a Greenland shark from the Western Caribbean, and being caught on a nearshore coral reef (the only other record of this species from the Caribbean was made from a deep-water habitat off the Caribbean coast of Colombia). The discovery indicates that Greenland sharks may have a wider distribution in the tropics, primarily at greater depths, than previously believed. Other behaviours The shark is often infested by the copepod Ommatokoita elongata, a crustacean which attaches itself to the shark's eyes. It was speculated that the copepod may display bioluminescence and thus attract prey for the shark in a mutualistic relationship, but this hypothesis has not been verified. These parasites also damage the eyeball in a number of ways, leading to almost complete blindness. 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 shark occupies what tends to be a very deep environment seeking its preferred cold water () habitat. Longevity The Greenland shark has the longest known lifespan of all vertebrate species. One Greenland shark was tagged off the coast of Greenland in 1936 and recaptured in 1952. Its measurements suggest that Greenland sharks grow at a rate of per year. In 2016, a study based on 28 specimens that ranged from in length used radiocarbon dating of crystals within the lenses of their eyes