---
title: "What the sources say about the Cookiecutter Shark | AnimalTracks.wiki"
description: "41 claims from the Cookiecutter Shark profile, each beside the words of the source that backs it."
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# What the sources say about the Cookiecutter Shark (*Isistius brasiliensis*)

> 41 claims from the Cookiecutter Shark profile, each beside the words of the source that backs it. A "..." marks a cut in a quote and [brackets] an insertion.

Profile: [Cookiecutter Shark](https://animaltracks.wiki/animals/cookiecutter-shark/)

## Kyne (2018). Isistius brasiliensis. The IUCN Red List of Threatened Species 2018: e.T41830A2956761.

https://doi.org/10.2305/iucn.uk.2018-2.rlts.t41830a2956761.en

| The page says | The source says |
| :--- | :--- |
| The IUCN Red List rates the species Least Concern. | IUCN Red List category: Least Concern (LC). |
| Least Concern | IUCN Red List category: Least Concern (LC). (note: stats.conservationStatus) |

## Carlisle et al. (2021). Integrating multiple chemical tracers to elucidate the diet and habitat of Cookiecutter Sharks. Scientific Reports.

https://doi.org/10.1038/s41598-021-89903-z

| The page says | The source says |
| :--- | :--- |
| Tropical and subtropical oceans worldwide | widely distributed throughout the world’s tropical and subtropical oceanic waters |
| plus squid | In terms of general prey types, stomachs included ~ 49% cephalopods (beaks, tissues) |
| It also eats squid, and many squid remains found in cookiecutter stomachs were estimated to come from squid often as large as the sharks themselves. | it appears that sharks will consume small squid whole, many of the squid remains were estimated to be from relatively large squid, often as large as the sharks themselves |
| Cookiecutter sharks live in tropical and subtropical oceans around the world. | widely distributed throughout the world’s tropical and subtropical oceanic waters |
| Fifteen caught off Hawaii in 2013 weighed 213 g on average. | Cookiecutter sharks (n = 15; 9 M, 6 F; mean TL = 33.5 cm ± 6.6 SD; min TL = 17.1 cm, max TL = 43.1 cm, mean mass = 213 g ± 113 SD) were collected off Hawaii in August and September of 2013 |
| weightKg: 0.213 | mean mass = 213 g (note: battleStats.weightKg) |

## Minaglia & Liegl (2024). Moonless night sky increases Isistius species (cookiecutter shark) and live human contact. PLOS ONE.

https://doi.org/10.1371/journal.pone.0291852

| The page says | The source says |
| :--- | :--- |
| Of the six bites by cookiecutter sharks (genus Isistius) on live people in Hawaiian waters, five came with the moon set and after dark. | 5 of the 6 Isistius spp . bites on live humans in Hawaiʻian waters occurred with the moon set and after nautical twilight end and before nautical twilight start. (note: 'after dark' paraphrases after nautical twilight end and before nautical twilight start; genus scope carried in the sentence) |
| A 2024 study counted seven confirmed attacks on live people ever documented, six of them in Hawaiian waters between 2009 and 2023. | Out of 7 ever-documented and confirmed attacks on live humans, 6 occurred in Hawaiʻian waters between the years 2009 and 2023 |
| Very rarely. | contact with live humans is exceedingly rare |
| dangerLevel: Medium | Out of 7 ever-documented and confirmed attacks on live humans (note: stats.dangerLevel) |

## Cookiecutter Shark (Isistius brasiliensis). Florida Museum of Natural History.

https://www.floridamuseum.ufl.edu/discover-fish/species-profiles/isistius-brasiliensis/

| The page says | The source says |
| :--- | :--- |
| glows underneath to lure big animals close | The light underside glows, attracting fish, whales, and sharks. |
| then spins to cut a round plug out of them | the small shark spins its body removing a cookie-shaped plug from the flesh of its prey |
| deep by day and near the surface at night | Found in deep water at depths below 3,281 feet (1000 m) during the day, cookiecutter sharks migrate vertically to surface waters at night to feed |
| Plugs of flesh cut from large fish, whales and seals | Common prey items include large fishes such as marlin, wahoo, dolphin, tuna, sharks, and stingrays as well as marine mammals including seals, whales, and dolphins. |
| A glowing underside that lures big animals in, then a spin that carves out a cookie-shaped plug | The light underside glows, attracting fish, whales, and sharks. It attaches itself to the prey and uses its serrated bottom teeth to cut out a perfectly circular chunk of flesh. |
| Its underside is covered in photophores, tiny light-producing organs that give off a greenish glow | network of tiny light-producing organs called photophores (Klimley. 2013). Photophores produce an even greenish colored glow on the underside of this shark. |
| The only gap on the underside is a dark collar around the gill region. | There is a distinct dark brown collar around the gill region. The entire ventral surface of the cookiecutter shark with the exception of the dark collar contains a network of tiny light-producing organs |
| The glow attracts fish, whales and sharks, and it appears similar to a small fish. | The glowing area appears similar to a small fish from the depths, prompting larger fish to approach in search of their next meal. |
| The glow attracts fish, whales and sharks | The light underside glows, attracting fish, whales, and sharks. |
| The shark bites when they come close. | Just prior to biting the cookiecutter shark, the large fish is unexpectedly bitten by the shark. |
| It grips with sucking lips and upper teeth, then spins its body to cut a cookie-shaped plug out of its prey with its larger lower teeth. | attaches itself to its prey with its sucking lips and sharp pointy upper teeth. Once it is attached, the small shark spins its body removing a cookie-shaped plug from the flesh of its prey with its larger serrated bottom teeth (note: 'serrated' left out: the 2018 PLOS ONE genus paper says the lower teeth are not serrated) |
| The prey is left with a perfectly round, cookie-cutter-shaped hole in its side. | The prey is left with a perfectly round cookie cutter-shaped hole in the side of its body |
| The Florida Museum lists marlin, wahoo, tuna, sharks, stingrays, seals, whales and dolphins among its prey. | Common prey items include large fishes such as marlin, wahoo, dolphin, tuna, sharks, and stingrays as well as marine mammals including seals, whales, and dolphins. |
| There are even reports of crater marks on the sonar domes of nuclear submarines. | There are reports of this shark leaving crater marks on the sonar domes of nuclear submarines. |
| They are found from the Bahamas to southern Brazil in the western Atlantic, and from Mauritius to New Guinea, New Zealand, Japan and the Hawaiian Islands in the Indo-Pacific. | found in the western Atlantic Ocean from the Bahamas south to the coast of southern Brazil ... the Indo-Pacific from Mauritius to New Guinea, Lord Howe Island, and New Zealand north to Japan and east to the Hawaiian Islands |
| By day they stay below 1,000 m. At night they rise to the surface waters to feed, a daily trip scientists call vertical migration. | Found in deep water at depths below 3,281 feet (1000 m) during the day, cookiecutter sharks migrate vertically to surface waters at night to feed |
| the Florida Museum considers the shark harmless to humans because of its size and deep-water habits | Because of its size and deep water habits, it is considered harmless to humans. |
| The teeth are connected at the base and lost as one complete unit, rather than one at a time like most sharks. | The teeth are interconnected at the bases, allowing the entire row of teeth to move if one tooth is touched (Compagno. 2005). The teeth are lost as a complete unit rather than individual teeth common to most sharks. |
| It swallows its shed lower teeth, which is thought to help maintain the calcium in its body. | As the lower teeth are shed, they are ingested by the shark. This is thought to aid in maintaining the calcium levels in the body |
| A litter holds 6 to 12 live young. | There are 6-12 live young born per litter |
| It sheds its lower teeth as one complete set and swallows them. The Florida Museum says this is thought to help the shark keep up its calcium levels. | As the lower teeth are shed, they are ingested by the shark. This is thought to aid in maintaining the calcium levels in the body |
| The small, cigar-shaped shark can be called a parasite, because it feeds on larger animals without killing them. | It can be considered a parasite due to its nature to feed on larger animals without killing them |
| The cookiecutter shark turns its own belly into a lure. | Prey items are attracted to the ventral surface of the cookiecutter shark due to the light given off by the glowing photophores |
| A cookiecutter shark grips with its lips and upper teeth, then spins its body to cut a round plug out of its prey | the small shark spins its body removing a cookie-shaped plug from the flesh of its prey (note: vibe.reason) |
| A cookiecutter shark grips with its lips and upper teeth, then spins its body to cut a round plug out of its prey | attaches itself to its prey with its sucking lips and sharp pointy upper teeth (note: vibe.reason) |

## Isistius brasiliensis (Quoy & Gaimard, 1824) Cookie cutter shark. FishBase.

https://www.fishbase.se/summary/Isistius-brasiliensis.html

| The page says | The source says |
| :--- | :--- |
| A shark up to 56 cm long that glows underneath to lure big animals close | females mature at 39 cm, with a maximum length of 56 cm |
| Males grow to a maximum of 42 cm and females to 56 cm. | Males mature at about 36 cm, with a maximum length of 42 cm; females mature at 39 cm, with a maximum length of 56 cm. |
| FishBase gives a maximum total length of 56 cm for a female and 42 cm for a male. | Males mature at about 36 cm, with a maximum length of 42 cm; females mature at 39 cm, with a maximum length of 56 cm. |
| Females are the larger sex. | Males mature at about 36 cm, with a maximum length of 42 cm; females mature at 39 cm, with a maximum length of 56 cm. |