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# What the sources say about the Giant Isopod (*Bathynomus giganteus*)

> 43 claims from the Giant Isopod profile, each beside the words of the source that backs it. A "..." marks a cut in a quote and [brackets] an insertion.

Profile: [Giant Isopod](https://animaltracks.wiki/animals/giant-isopod/)

## McClain et al. (2015). Sizing ocean giants: patterns of intraspecific size variation in marine megafauna. PeerJ.

https://doi.org/10.7717/peerj.715

| The page says | The source says |
| :--- | :--- |
| has been reported to survive eight weeks between meals in an aquarium | Specimens in aquaria have survived 8 weeks between feedings ( Cocke, 1986 ) (note: The figure comes from Cocke (1986), an article in the hobby magazine Tropical Fish Hobbyist, cited by McClain et al.; 'has been reported' carries that attribution.) |
| Continental slopes of the Gulf of Mexico and Caribbean Sea, typically 310 to 1,800 meters down, less commonly the US Atlantic coast as far north as Georgia | Bathynomus giganteus are abundant scavengers distributed throughout the Gulf of Mexico and Caribbean Sea on upper- and mid-continental slopes at depths typically ranging from 310 to 1800 m ... Though less abundant, giant isopods are also found along the eastern coast of the United States as far north as Georgia ( Lowry & Dempsey, 2006 ). |
| A scavenger that can also hunt live prey | Bathynomus giganteus is a scavenger ( Holthuis & Mikulka, 1972 ; Cocke, 1986 ; Briones-Fourzán & Lozano-Álvarez, 1991 ) or facultative predator ( Holthuis & Mikulka, 1972 ; Briones-Fourzán & Lozano-Álvarez, 1991 ). (note: 'facultative predator' rendered as 'can also hunt live prey'.) |
| A big body that can hold large fat reserves, which may help it fast when food is scarce and sporadic. | Thus, the large size of B. giganteus may serve as an adaptation to low and sporadic food availability by increasing fasting potential because greater fat reserves can be maintained |
| Not Evaluated | The giant deep-sea isopod Bathynomus giganteus is the largest known isopod species. (note: No IUCN Red List assessment exists for Bathynomus giganteus: GBIF's copy of the Red List has no category for the name and Crossref has no assessment DOI, checked 2026-09-16. Boos et al. (2021) assessed its extinction risk as Least Concern, but that is the authors' own assessment, not a Red List one.) |
| A 2015 study of ocean giants called it the largest known isopod species. | The giant deep-sea isopod Bathynomus giganteus is the largest known isopod species. |
| It lives on the continental slopes of the Gulf of Mexico and the Caribbean Sea, typically 310 to 1,800 meters down | Bathynomus giganteus are abundant scavengers distributed throughout the Gulf of Mexico and Caribbean Sea on upper- and mid-continental slopes at depths typically ranging from 310 to 1800 m ... Though less abundant, giant isopods are also found along the eastern coast of the United States as far north as Georgia ( Lowry & Dempsey, 2006 ). (note: The closing clause 'where the seafloor drops away from the edge of the land' defines a continental slope and states nothing about the species.) |
| It is less common along the US Atlantic coast, as far north as Georgia. | Bathynomus giganteus are abundant scavengers distributed throughout the Gulf of Mexico and Caribbean Sea on upper- and mid-continental slopes at depths typically ranging from 310 to 1800 m ... Though less abundant, giant isopods are also found along the eastern coast of the United States as far north as Georgia ( Lowry & Dempsey, 2006 ). |
| As of that 2015 study, the largest giant isopod documented in the scientific literature measured 50 centimeters (about 20 inches). | The largest giant isopod documented in the scientific literature is a more conservative 50 cm ( Lowry & Dempsey, 2006 ). (note: 50 cm converted to about 20 inches (19.7 in). Dated to the study because it is a record.) |
| A 76-centimeter giant was reported in the popular media, but it could not be confirmed with an actual measurement. | An individual measuring 76 cm in length was reported in the popular media but cannot be confirmed with actual measurements ( Daily Mail Reporter, 2010 ). |
| Giant isopods kept in aquariums have survived eight weeks between feedings | Specimens in aquaria have survived 8 weeks between feedings ( Cocke, 1986 ) |
| according to a 1986 aquarium magazine article. | Cocke (1986) Cocke BT. Deep-sea isopods in aquaria. Tropical Fish Hobbyist. (note: Cocke (1986), the source McClain et al. cite for the 8-week figure, is an article in Tropical Fish Hobbyist, an aquarium hobby magazine.) |
| Scientists think their large size may be an adaptation to food that is scarce and sporadic: a bigger body can hold bigger fat reserves, so it can fast for longer. | Thus, the large size of B. giganteus may serve as an adaptation to low and sporadic food availability by increasing fasting potential because greater fat reserves can be maintained |
| Giant isopods do store large amounts of fat in their hepatopancreas | Further support for this hypothesis is the large quantities of lipid reserves in the hepatopancreas ( Steves, 1969 ) and fat bodies ( Biesot et al., 1999 ) of this isopod. (note: 'lipid' rendered as 'fat'. 'a digestive gland' glosses the term; Biesot et al. (1999) in the same reference list call it the midgut gland.) |
| A bigger body also lets an animal search a larger area for food, which matters to scavengers and predators alike. | Larger size also confers a greater foraging area, which is important for both scavengers and predators. |
| Giant isopods are scavengers, feeding on animals that are already dead, and facultative predators, which means they can hunt live prey but do not depend on it. | Bathynomus giganteus is a scavenger ( Holthuis & Mikulka, 1972 ; Cocke, 1986 ; Briones-Fourzán & Lozano-Álvarez, 1991 ) or facultative predator ( Holthuis & Mikulka, 1972 ; Briones-Fourzán & Lozano-Álvarez, 1991 ). (note: 'feeding on animals that are already dead' and 'can hunt live prey but do not depend on it' define scavenger and facultative predator.) |
| Giant isopods (Bathynomus giganteus) kept in aquariums have survived eight weeks between feedings | Specimens in aquaria have survived 8 weeks between feedings ( Cocke, 1986 ) |
| according to a 1986 aquarium magazine article. | Cocke (1986) Cocke BT. Deep-sea isopods in aquaria. Tropical Fish Hobbyist. (note: Cocke (1986), the source McClain et al. cite for the 8-week figure, is an article in Tropical Fish Hobbyist, an aquarium hobby magazine.) |
| Scientists think their large size may help them fast when food is scarce and sporadic, because a bigger body can hold bigger fat reserves. | Thus, the large size of B. giganteus may serve as an adaptation to low and sporadic food availability by increasing fasting potential because greater fat reserves can be maintained |
| As of a 2015 study, the largest giant isopod documented in the scientific literature measured 50 centimeters (about 20 inches). | The largest giant isopod documented in the scientific literature is a more conservative 50 cm ( Lowry & Dempsey, 2006 ). (note: 50 cm converted to about 20 inches (19.7 in).) |
| A 76-centimeter giant was reported in the popular media, but it could not be confirmed with an actual measurement. | An individual measuring 76 cm in length was reported in the popular media but cannot be confirmed with actual measurements ( Daily Mail Reporter, 2010 ). |
| Giant isopods are scavengers, which means they feed on animals that are already dead. | Bathynomus giganteus is a scavenger ( Holthuis & Mikulka, 1972 ; Cocke, 1986 ; Briones-Fourzán & Lozano-Álvarez, 1991 ) or facultative predator ( Holthuis & Mikulka, 1972 ; Briones-Fourzán & Lozano-Álvarez, 1991 ). (note: The second clause defines scavenger.) |
| They are also facultative predators: they can hunt live prey, but they do not depend on it. | Bathynomus giganteus is a scavenger ( Holthuis & Mikulka, 1972 ; Cocke, 1986 ; Briones-Fourzán & Lozano-Álvarez, 1991 ) or facultative predator ( Holthuis & Mikulka, 1972 ; Briones-Fourzán & Lozano-Álvarez, 1991 ). (note: The clause after the colon defines facultative predator.) |
| said to last eight weeks between meals in aquariums | Specimens in aquaria have survived 8 weeks between feedings ( Cocke, 1986 ) (note: From Cocke (1986), a hobby-magazine article cited by McClain et al.; 'said to' carries that attribution.) |

## Boos, Scalco & Araujo (2021). Biological and ecological traits of Bathynomus giganteus and Bathynomus miyarei (Crustacea: Isopoda): Contribution to the conservation of deep-sea in southern Brazil. Aquatic Conservation: Marine and Freshwater Ecosystems.

https://doi.org/10.1002/aqc.3583

| The page says | The source says |
| :--- | :--- |
| deep water off southern Brazil | Bathynomus giganteus (663 specimens) and B. miyarei (649 specimens) were collected during five research cruises involving 265 h of sampling effort during 32 fishing operations of circular pots, baited traps, ranging from 400 and 1,000 m deep, between 26 and 29°S adjacent to the Brazilian coast. ... Bathynomus giganteus were collected between 600 m and 1,000 m depth |
| A 2021 study caught 663 giant isopods in baited traps off southern Brazil, between 600 and 1,000 meters deep. | Bathynomus giganteus (663 specimens) and B. miyarei (649 specimens) were collected during five research cruises involving 265 h of sampling effort during 32 fishing operations of circular pots, baited traps, ranging from 400 and 1,000 m deep, between 26 and 29°S adjacent to the Brazilian coast. ... Bathynomus giganteus were collected between 600 m and 1,000 m depth |
| It estimated that males there mature at about 34 centimeters long and live about 6 years | The sexual maturity of B. giganteus was estimated at 340–345 mm total length for males and between 280–290 mm for females. ... The longevity of B. giganteus was estimated at 6 years for males and 7.7 years for females. (note: 340-345 mm rounded to about 34 cm. Scope kept to the southern Brazil sample the study estimated from.) |
| while females mature at 28 to 29 centimeters and live about 7.7 years | The sexual maturity of B. giganteus was estimated at 340–345 mm total length for males and between 280–290 mm for females. ... The longevity of B. giganteus was estimated at 6 years for males and 7.7 years for females. (note: 280-290 mm converted to 28 to 29 cm. 'estimated' in the preceding clause governs this one.) |

## Chamberlain, Meyer-Rochow & Dossert (1986). Morphology of the compound eye of the giant deep-sea isopod Bathynomus giganteus. Journal of Morphology.

https://doi.org/10.1002/jmor.1051890205

| The page says | The source says |
| :--- | :--- |
| with about 3,500 lenses in each eye | Each eye contains about 3,500 ommatidia in animals of body lengths from 22.5 cm to 37.5 cm. ... The dioptric elements in each ommatidium consist of a laminar cornea (note: An ommatidium's dioptric (light-focusing) elements, its cornea and crystalline cone, rendered as a lens. Measured in animals 22.5 to 37.5 cm long.) |
| A 1986 study described the eyes of four giant isopods kept alive in a lab. | The structural organization of the compound eye of the largest known isopod, Bathynomus giganteus, is described from four specimens maintained in the laboratory for as long as two months. |
| In animals 22.5 to 37.5 centimeters long, each of the two compound eyes held about 3,500 ommatidia | Each eye contains about 3,500 ommatidia in animals of body lengths from 22.5 cm to 37.5 cm. |
| tiny units that each have their own lens and light-sensing cells | The dioptric elements in each ommatidium consist of a laminar cornea, which is flat externally and convex internally, and a bipartite crystalline cone. Sometimes seven and sometimes eight retinular cells closely appose the proximal tip of the cone and bear the microvilli of the rhabdom. (note: The cornea and cone (dioptric elements) rendered as a lens; the retinular cells are the photoreceptors the abstract's last sentence names.) |
| Being brought up from the deep into daylight appeared to cause permanent damage to the light-sensing cells of these animals. | Animals were fixed both in light within a week of being brought from depth into daylight ... Exposure to natural daylight appears to cause irreversible structural damage to the photoreceptors of these animals. (note: 'photoreceptors' rendered as 'light-sensing cells', 'irreversible' as 'permanent'.) |

## Pless et al. (2003). Latent phenoloxidase activity and N-terminal amino acid sequence of hemocyanin from Bathynomus giganteus, a primitive crustacean. Archives of Biochemistry and Biophysics.

https://doi.org/10.1016/s0003-9861(02)00615-x

| The page says | The source says |
| :--- | :--- |
| Hemocyanin is the protein that carries oxygen in a giant isopod's blood. | The hemocyanin of this primitive crustacean may fulfill dual functions, both as oxygen carrier and as the phenoloxidase crucial for host defense. (note: The abstract's hedge ('may') applies to the dual role; hemocyanin as oxygen carrier is the premise. 'blood' stands for hemolymph.) |
| In a 2003 lab study, purified hemocyanin from giant isopods worked as phenoloxidase, an enzyme, once a chemical was added to switch it on. | purified hemocyanin from B. giganteus exhibited phenoloxidase activity in the presence of sodium dodecyl sulfate. Although a natural activator has not yet been identified (note: Sodium dodecyl sulfate rendered as 'a chemical ... to switch it on', since the abstract contrasts it with a natural activator.) |
| Early measurements of the enzyme were consistent with an important role in the animal's immune system, though the natural switch had not been found. | Although a natural activator has not yet been identified, a preliminary study of the enzyme indicated a K(m) of 5mM for dopamine and an initial rate of 0.1 micromol per min per mg protein, values consistent with a significant role for this enzyme in the innate immune system of B. giganteus. |
| The researchers suggested one molecule may do two jobs: carrying oxygen and defending the body. | The hemocyanin of this primitive crustacean may fulfill dual functions, both as oxygen carrier and as the phenoloxidase crucial for host defense. |
| One Molecule, Maybe Two Jobs | The hemocyanin of this primitive crustacean may fulfill dual functions, both as oxygen carrier and as the phenoloxidase crucial for host defense. |

## Chaves-Aguilar et al. (2025). Caracterización biológica del isópodo gigante (Bathynomus giganteus) en aguas profundas del Caribe colombiano. Revista de la Academia Colombiana de Ciencias Exactas, Físicas y Naturales.

https://doi.org/10.18257/raccefyn.3090

| The page says | The source says |
| :--- | :--- |
| tags: benthic | Este isópodo habita fondos blandos ... El cuerpo de B. giganteus es aplanado dorsoventralmente, lo que le permite moverse con facilidad sobre el sedimento del fondo marino y enterrarse en él. (note: Benthic is "living on the bottom of aquatic bodies, crawling over sediments": the source has B. giganteus living on soft bottoms and moving over seafloor sediment. Replaces the abyssal tag removed in #470, which the 310-1,800 m continental-slope range contradicted.) |

## Giant Isopod. NOAA Ocean Exploration.

https://oceanexplorer.noaa.gov/multimedia/daily-image-media-20210816/

| The page says | The source says |
| :--- | :--- |
| one was seen snacking on a fish head | The other giant isopod we encountered was observed snacking on a fish head . |
| is a deep-sea scavenger and a close relative of the pill bugs, roly-polies and sowbugs found in houses and gardens, but much, much larger | These deep-sea scavengers are close relatives of the pill bugs, rolly pollies, and sowbugs found in houses and gardens, but Bathynomus giganteus is much, much larger |
| A NOAA expedition about 65 kilometers southeast of Key West, Florida, saw one snacking on a fish head in 2019. | This was one of two giant isopods ( Bathynomous giganteus ) seen while exploring a site about 65 kilometers (40 miles) southeast of Key West, Florida, as part of the 2019 Southeastern U.S. Deep-sea Exploration . The other giant isopod we encountered was observed snacking on a fish head . |
| Giant isopods are deep-sea scavengers and close relatives of the pill bugs, roly-polies and sowbugs found in houses and gardens, but much, much larger. | These deep-sea scavengers are close relatives of the pill bugs, rolly pollies, and sowbugs found in houses and gardens, but Bathynomus giganteus is much, much larger |