---
title: "What the sources say about the Greenland Shark | AnimalTracks.wiki"
description: "62 claims from the Greenland Shark profile, each beside the words of the source that backs it."
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# What the sources say about the Greenland Shark (*Somniosus microcephalus*)

> 62 claims from the Greenland Shark profile, each beside the words of the source that backs it. A "..." marks a cut in a quote and [brackets] an insertion.

Profile: [Greenland Shark](https://animaltracks.wiki/animals/greenland-shark/)

## Somniosus microcephalus (Greenland shark). Animal Diversity Web, University of Michigan.

https://animaldiversity.org/accounts/Somniosus_microcephalus/

| The page says | The source says |
| :--- | :--- |
| lives in water as cold as 1 degree Celsius | in waters from 1 to 12 degrees Celsius |
| it eats cod, herring, skates, seals, and small whales | Fish include herring (Clupeinae), salmon (Salmonidae), smelt (Osmeridae), cod (Gadidae), pollock (Theragra), haddock (Melanogrammus), halibut (Hippoglossus), redfish (Hoplostethus), sculpins (Cottoidei), lumpfish (Cyclopterus), and skates (Rajiformes). Seals (Phocidae) and small whales (Delphinidae) are also common food items. |
| drowned horses and reindeer have turned up in the stomachs of captured sharks | Drowned horses and reindeer have also been found in the stomachs of captured specimens. |
| Many Greenland sharks have a copepod, Ommatokoita elongata, attached to the cornea of one eye | Many of these sharks have copepod parasites ... attached to the corneas of their eyes. A single, female copepod will attach itself to one of the corneas |
| but that does not seem to harm the shark, since it does not rely on its vision | This does not seem to negatively effect the shark, as they do not rely on their vision. |
| Cod, herring, skates | herring (Clupeinae), salmon (Salmonidae), smelt (Osmeridae), cod (Gadidae) ... and skates (Rajiformes) (note: stats.diet) |
| seals, and small whales, plus carrion such as reindeer and horse carcasses | Seals (Phocidae) and small whales (Delphinidae) are also common food items ... Drowned horses and reindeer have also been found in the stomachs of captured specimens. (note: stats.diet) |
| Many Greenland sharks have a parasitic copepod, Ommatokoita elongata, attached to one eye | Many of these sharks have copepod parasites ... attached to the corneas of their eyes. A single, female copepod will attach itself to one of the corneas (note: faq 3; replaces 'On most Greenland sharks ... usually', which read Florida's one-eye-per-shark sentence as a prevalence figure) |
| no attack on a person has been confirmed | However, no attacks on humans by this species have been confirmed. (note: body; the sentence stats.dangerLevel: Medium rests on) |

## How long do Greenland sharks live? National Ocean Service, NOAA.

https://oceanservice.noaa.gov/facts/greenland-shark.html

| The page says | The source says |
| :--- | :--- |
| growing under a centimeter a year | the sharks grow at a very slow rate (less than 1 cm per year) (note: tagline) |
| cruises the deep, cold water | an adaptation to the deep, cold waters it inhabits |
| Its skeleton has no hard, calcified tissue to grow rings on, the way other sharks are aged | The age of other shark species can be estimated by counting growth bands on fin spines or on the shark's vertebrae ... Greenland sharks, however, have no fin spines and no hard tissues in their bodies. Their vertebrae are too soft to form the growth bands seen in other sharks. |
| proteins formed before birth that do not degrade with age | Inside the shark's eyes, there are proteins that are formed before birth and do not degrade with age |
| The largest shark in the study, a five-meter female, worked out to somewhere between 272 and 512 years old | The largest shark they found, a 5-meter female, was between 272 and 512 years old according to their estimates. (note: matches Nielsen 2016's own figure for its largest specimen (502 cm, 392 ± 120 years = 272-512 years)) |
| A Greenland shark grows less than a centimeter a year | the sharks grow at a very slow rate (less than 1 cm per year) |
| is known to dive as deep as 2,200 meters | these sharks are known to dive as deep as 2,200 meters |
| It grows less than a centimeter a year | the sharks grow at a very slow rate (less than 1 cm per year) (note: stats.superpower) |
| known to dive as deep as 2,200 meters | these sharks are known to dive as deep as 2,200 meters (note: stats.habitat) |
| that other sharks are aged by, so there are no growth rings to count | The age of other shark species can be estimated by counting growth bands on fin spines or on the shark's vertebrae ... Their vertebrae are too soft to form the growth bands seen in other sharks. (note: faq 1; replaces 'because Greenland sharks have no bones', a cause no source gives (no shark has bones, yet other sharks are aged)) |
| The largest shark in the study, a five-meter female, worked out to somewhere between 272 and 512 years old | The largest shark they found, a 5-meter female, was between 272 and 512 years old according to their estimates. (note: faq 1; the FAQ's ref states it too: 'the largest animal (502 cm) to be 392 ± 120 years old') |

## Somniosus microcephalus. Florida Museum of Natural History, Discover Fishes.

https://www.floridamuseum.ufl.edu/discover-fish/species-profiles/greenland-shark/

| The page says | The source says |
| :--- | :--- |
| of the North Atlantic and Arctic Ocean | The shark is typically found in the Northern Atlantic and Arctic regions. |
| swims slowly | it is a slow swimmer |
| Greenland sharks average roughly 2.4 to 4.3 meters long | Greenland sharks average in size from 244 to 427 cm (note: 244 cm = 2.44 m, 427 cm = 4.27 m, rounded to 2.4 and 4.3; ADW gives the same 'Average length 244 to 427 cm') |
| the biggest reach about 6.4 meters | This shark reaches a maximum length of about 640 cm (21 feet) (note: 640 cm = 6.4 m; replaces 'the largest confirmed Greenland shark stretched 6.4 meters', which turned the top of ADW's length range into a confirmed record) |
| Females are the larger sex | with females being the larger sex |
| plus eels, flounders, and other small sharks | The shark's most common food consists of a large variety of ocean dwellers such as other small sharks, skates, eels, herring, capelin, char, various gadoids, redfish, sculpins, lumpfish, wolfish, and flounders. |
| It is a slow swimmer that likely ambushes its prey, and it eats carrion too | it is a slow swimmer, and likely ambushes its prey and scavenges for carrion |
| Cold North Atlantic and Arctic Ocean waters | The shark is typically found in the Northern Atlantic and Arctic regions. (note: stats.habitat) |
| from the surface to about 1,200 meters, in water between 1 and 12 degrees Celsius | The shark ranges in depths of 0-3,937 feet (0 to 1,200 m) and temperatures of 34-68°F (1 to 12°C). (note: stats.habitat; Florida states the range for the species, where ADW's identical figures are scoped to 'northern parts of their range') |
| eels | other small sharks, skates, eels, herring (note: stats.diet) |
| the International Shark Attack File lists only one reported attack | According to the International Shark Attack File (ISAF) there has only been one reported attack of the Greenland shark on a human. (note: body; stats.dangerLevel) |
| swims slowly | it is a slow swimmer (note: vibe.reason (women artists, round 2)) |

## Nielsen et al. (2016). Eye lens radiocarbon reveals centuries of longevity in the Greenland shark (Somniosus microcephalus). Science.

https://doi.org/10.1126/science.aaf1703

| The page says | The source says |
| :--- | :--- |
| The longest-lived vertebrate known to science | the Greenland shark is the longest-lived vertebrate known |
| with females not sexually mature until at least 156 years old, give or take 22 | as females are reported to reach sexual maturity at lengths >400 cm ... the corresponding age would be at least 156 ± 22 (note: tagline; female scope and the ± 22 restored (the estimate is for females, whose maturity length is >400 cm)) |
| it grows slowly | grows slowly and reaches >500 centimeters (cm) in total length |
| lives longer than any other backboned animal known | the Greenland shark is the longest-lived vertebrate known |
| no hard, calcified tissue | Conventional growth zone chronologies cannot be used to age Greenland shark due to the lack of calcified tissues |
| In 2016, researchers found a workaround | The definitive version was published in Science on vol. 353, issue 6300. Aug. 12, 2016 (note: body; sources the bare '2016' figure to the paper's publication date) |
| the center of a shark's eye lens is made of proteins formed before birth | the eye lens nucleus is composed of metabolically inert crystalline proteins, which in the center (i.e., the embryonic nucleus) is formed during prenatal development |
| By radiocarbon-dating the eye lenses of 28 female Greenland sharks, a team calculated a lifespan of at least 272 years, making it the longest-lived vertebrate known | Radiocarbon dating of eye lens nuclei from 28 female Greenland sharks (81 to 502 cm in total length) revealed a life span of at least 272 years ... Our results show that the Greenland shark is the longest-lived vertebrate known |
| the same data put sexual maturity in females at no younger than 156 years old, give or take 22 | as females are reported to reach sexual maturity at lengths >400 cm ... the corresponding age would be at least 156 ± 22 (note: scope: females only, from the same 28-shark chronology; '± 22' restored) |
| females aren't sexually mature until at least 156 years old, give or take 22 | as females are reported to reach sexual maturity at lengths >400 cm ... the corresponding age would be at least 156 ± 22 (note: stats.superpower) |
| its lifespan runs to at least 272 years, the longest of any known vertebrate | revealed a life span of at least 272 years ... the Greenland shark is the longest-lived vertebrate known (note: stats.superpower; replaces 'can live past 272 years' ('past' for 'at least') and the unsourced 'A metabolism so slow' cause (NOAA offers slow metabolism only as 'one theory')) |
| Greenland sharks lack the calcified tissue | Conventional growth zone chronologies cannot be used to age Greenland shark due to the lack of calcified tissues (note: faq 1) |
| In a 2016 study | The definitive version was published in Science on vol. 353, issue 6300. Aug. 12, 2016 (note: faq 1; sources the bare '2016' figure to the paper's publication date) |
| scientists radiocarbon-dated the eye lenses of 28 female sharks | Radiocarbon dating of eye lens nuclei from 28 female Greenland sharks (81 to 502 cm in total length) |
| the center of the lens is made of proteins formed before birth | the eye lens nucleus is composed of metabolically inert crystalline proteins, which in the center (i.e., the embryonic nucleus) is formed during prenatal development (note: faq 1 parenthetical) |
| calculated a lifespan of at least 272 years, making it the longest-lived vertebrate known | revealed a life span of at least 272 years ... Our results show that the Greenland shark is the longest-lived vertebrate known (note: faq 1) |
| grows slowly | grows slowly and reaches >500 centimeters (cm) in total length (note: vibe.reason (women artists, round 2)) |
| has a lifespan of at least 272 years | revealed a life span of at least 272 years (note: vibe.reason (women artists, round 2)) |

## Nielsen et al. (2020). Assessing the reproductive biology of the Greenland shark (Somniosus microcephalus). PLOS ONE.

https://doi.org/10.1371/journal.pone.0238986

| The page says | The source says |
| :--- | :--- |
| two in one study weighed 1,100 and 1,367 kilograms | two Stage 3 females in our study weighed 1,100 kg and 1,367 kg (note: replaces ADW's 'Range mass 700 to 1000 kg', which cannot cover ADW's own 40-640 cm length range and sits below both of these weighed females) |
| Researchers estimate a litter could hold up to 200 to 324 pups, depending on the mother's size, each about 35 to 45 centimeters long at birth | we estimate up to 200–324 pups per pregnancy (depending on maternal size) with a body length-at-birth of 35–45 cm |
| though that estimate is still waiting to be checked against a pregnant shark | These estimates remain to be verified by future observations from gravid Greenland sharks. |

## Anthoni et al. (1991). Poisonings from flesh of the Greenland shark Somniosus microcephalus may be due to trimethylamine. Toxicon.

https://doi.org/10.1016/0041-0101(91)90193-u

| The page says | The source says |
| :--- | :--- |
| Greenland shark flesh, especially fresh, is toxic to both dogs and people | The flesh of the Greenland shark, Somniosus microcephalus, especially in fresh condition, is toxic to both dog and man. |
| It carries large amounts of trimethylamine oxide, and the poisoning symptoms appear to come from that chemical breaking down in the gut into trimethylamine | the presence of large amounts of trimethylamine oxide (TMAO) but no other substances that could be directly responsible for the poisoning. The symptoms appear to be due to an acute trimethylamine (TMA) poisoning arising from intestinal reduction of TMAO to TMA. |
| Its flesh carries large amounts of trimethylamine oxide (TMAO). The poisoning appears to come from TMAO breaking down in the gut into trimethylamine (TMA), and the fresh flesh is toxic to both dogs and people | the flesh of the Greenland shark ... is toxic to both dog and man ... the presence of large amounts of trimethylamine oxide (TMAO) ... The symptoms appear to be due to an acute trimethylamine (TMA) poisoning arising from intestinal reduction of TMAO to TMA. |

## Borucinska, Benz & Whiteley (1998). Ocular lesions associated with attachment of the parasitic copepod Ommatokoita elongata (Grant) to corneas of Greenland sharks, Somniosus microcephalus (Bloch & Schneider). Journal of Fish Diseases.

https://doi.org/10.1046/j.1365-2761.1998.00122.x

| The page says | The source says |
| :--- | :--- |
| It can scar the cornea and could lead to severe vision loss, possibly blindness | fibrosis of the corneal substantia propria ... parasitism by O. elongata could lead to severe vision impairment (possibly including blindness) in Greenland sharks |
| Researchers who examined infected eyes found corneal ulcers and scarring, and concluded the parasite could lead to severe vision impairment, possibly including blindness | corneal epithelial ulceration and heterophilic keratitis ... fibrosis of the corneal substantia propria ... parasitism by O. elongata could lead to severe vision impairment (possibly including blindness) in Greenland sharks |
| Yet the infected sharks looked otherwise healthy, and the infection doesn't seem to seriously weaken them | the otherwise healthy appearance of the infected sharks studied and the information contained in the literature suggests that O. elongata infections do not significantly debilitate the hosts |

## Osimani et al. (2019). Unveiling hákarl: A study of the microbiota of the traditional Icelandic fermented fish. Food Microbiology.

https://doi.org/10.1016/j.fm.2019.03.027

| The page says | The source says |
| :--- | :--- |
| In Iceland, the flesh is traditionally cured into a fermented dish called hákarl instead of eaten fresh | Hákarl is produced by curing of the Greenland shark (Somniosus microcephalus) flesh, which before fermentation is toxic due to the high content of trimethylamine (TMA) or trimethylamine N-oxide (TMAO). |
| Icelanders traditionally cure the meat into a fermented dish called hákarl instead of eating it fresh | Hákarl is produced by curing of the Greenland shark (Somniosus microcephalus) flesh |

## Kulka et al. (2020). Somniosus microcephalus. The IUCN Red List of Threatened Species 2020: e.T60213A124452872.

https://doi.org/10.2305/iucn.uk.2020-3.rlts.t60213a124452872.en

| The page says | The source says |
| :--- | :--- |
| Vulnerable | IUCN Red List category: Vulnerable (VU). (note: stats.conservationStatus) |