---
title: "What the sources say about the Common Octopus | AnimalTracks.wiki"
description: "56 claims from the Common Octopus profile, each beside the words of the source that backs it."
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canonical: "https://animaltracks.wiki/animals/common-octopus/sources/"
---

# What the sources say about the Common Octopus (*Octopus vulgaris*)

> 56 claims from the Common Octopus profile, each beside the words of the source that backs it. A "..." marks a cut in a quote and [brackets] an insertion.

Profile: [Common Octopus](https://animaltracks.wiki/animals/common-octopus/)

## Allcock, Headlam & Allen (2018). Octopus vulgaris. The IUCN Red List of Threatened Species 2018: e.T162571A918906.

https://doi.org/10.2305/iucn.uk.2018-2.rlts.t162571a918906.en

| The page says | The source says |
| :--- | :--- |
| Least Concern | Least Concern (note: stats.conservationStatus; assessed 2016 (published in the 2018 release); category read through GBIF's copy of the Red List) |
| The IUCN Red List assessment published in 2018 rates Octopus vulgaris as Least Concern. | Least Concern (note: faq; published in the 2018 release (per the DOI); the assessment year is not in the cached text, so it was cut; category read through GBIF's copy of the Red List) |

## Messenger (2001). Cephalopod chromatophores: neurobiology and natural history. Biological Reviews.

https://doi.org/10.1017/s1464793101005772

| The page says | The source says |
| :--- | :--- |
| whose colour-changing skin is run by over half a million neurons | In Octopus vulgaris there are over half a million neurons in the chromatophore lobes (note: tagline; stats.superpower) |
| Skin patterns carried out by over half a million neurons in the chromatophore lobes of its brain | at the lowest level, motoneurons in the chromatophore lobes execute the programmes, their activity or inactivity producing the patterning seen in the skin. In Octopus vulgaris there are over half a million neurons in the chromatophore lobes (note: stats.superpower) |
| Cephalopods (the octopus and squid group) change their appearance with chromatophores. | Neural control of the chromatophores enables a cephalopod to change its appearance almost instantaneously |
| Each one is an organ in the skin: an elastic sac of pigment with muscles attached. | they are neuromuscular organs rather than cells ... Each chromatophore organ comprises an elastic sacculus containing pigment, to which is attached a set of obliquely striated radial muscles |
| When the muscles contract, the sac expands. When they relax, the sac springs back using the energy it stored. | When excited the muscles contract, expanding the chromatophore; when they relax, energy stored in the elastic sacculus retracts it. |
| the optic lobes of the brain, which work largely on visual information, choose a body pattern | At the highest level, the optic lobes, acting largely on visual information, select specific motor programmes (i.e. body patterns) |
| That plan is carried out by the chromatophore lobes, which in Octopus vulgaris hold over half a million neurons. | at the lowest level, motoneurons in the chromatophore lobes execute the programmes ... In Octopus vulgaris there are over half a million neurons in the chromatophore lobes |
| Skin Run by Half a Million Neurons | In Octopus vulgaris there are over half a million neurons in the chromatophore lobes (note: heading) |

## Cephalopods of the world, Volume 3: Octopods and vampire squids. FAO Species Catalogue for Fishery Purposes No. 4, Vol. 3.

https://www.fao.org/3/i3489e/i3489e.pdf

| The page says | The source says |
| :--- | :--- |
| estimated to live one to two years | Longevity of this species has been estimated in the range of one to two years. (note: tagline) |
| Rocky, sandy and muddy seabeds | lives on the continental shelf on rocky, sandy or muddy substrates (note: stats.habitat) |
| from the shore down to 250 m | This species has been reported from depths ranging from 0 to 250 m (note: stats.habitat) |
| in the Mediterranean and north-east Atlantic | Octopus vulgaris sensu stricto Mediterranean Sea, central and north - east Atlantic Ocean (note: stats.habitat) |
| Crustaceans (typically crabs and lobsters), fish and shelled molluscs | from crustaceans (typically crabs and lobsters), to fish (when they can be caught), to a range of shelled molluscs (note: stats.diet) |
| The FAO catalogue lists its living colours as yellow brown, red brown, dark brown or grey. | Colour in life variable from yellow brown, to red brown, dark brown or grey. |
| The name Octopus vulgaris has covered look-alike forms in several oceans, which the FAO catalogue calls a species complex in urgent need of revision. | The geographically disjunct forms (Fig. 39) are treated here under the following names ... This species complex is in urgent need of revision |
| treats Octopus vulgaris in the strict sense as the form of the Mediterranean and the central and north-east Atlantic | Octopus vulgaris sensu stricto Mediterranean Sea, central and north - east Atlantic Ocean |
| the south coast of England, north-west and west Africa, the Azores, the Canary Islands and the Cape Verde Islands | South coast of England; north - west and west coast of Africa; Azores, Canary Islands and Cape Verde Islands. |
| a mantle (body sac) 400 mm long, a total length of around 1.8 m and a weight of over 20 kg | * Based on Mediterranean and north - east Atlantic material (see Remarks above). Size: Mantle length to 400 mm; total length to around 1.8 m; body weight to over 20 kg. |
| A common size is a mantle of 250 mm. | Common at smaller size (250 mm ML). Geographical Distribution : Mediterranean Sea (note: body) |
| Its arms are 4 to 5.5 times the mantle length, each with two rows of suckers | Arms long (4 to 5.5 times mantle length) |
| two rows of suckers | Two rows of suckers on each arm. |
| in larger animals each normal arm carries around 220 to 320 of them | In larger animals, around 220 to 320 suckers on each normal arm. |
| Its longevity is estimated at one to two years. | Longevity of this species has been estimated in the range of one to two years. |
| on the continental shelf | lives on the continental shelf on rocky, sandy or muddy substrates |
| It has been recorded from the shoreline to 250 m deep, but typically lives shallower than 100 m. | reported from depths ranging from 0 to 250 m, but typically occurs shallower than 100 m |
| primarily active at night and typically spends the day in a den | This species is primarily night active, typically spending daylight hours within a den. |
| a crevice in a reef or one the octopus builds in soft sediment, sometimes using loose rocks or shells | Dens can consist of pre - existing crevices in rocky reefs and rubble or can be constructed by the octopus in softer sediments, sometimes incorporating loose rocks or shells. |
| probes for prey by touch with its upper arm pairs, or wraps its arm crown around a rock and uses the arm tips to detect and flush prey out | This species feeds by tactile probing for prey by the dorsal arm pairs or by enveloping rocks within the arm crown and webs and using the arm tips to detect and flush prey. |
| Crabs and lobsters are typical meals, fish when it can catch them, and shelled molluscs | from crustaceans (typically crabs and lobsters), to fish (when they can be caught), to a range of shelled molluscs |
| which it typically gets into by boring a hole with its toothed salivary papillae, paralysing or relaxing the animal inside | The latter group typically are extracted by drilling through the shell with the toothed salivary papillae to paralyse/relax the occupant |
| Cannibalism has been recorded. | Cannibalism also has been recorded for this species. |
| Its predators include sharks and many fishes, among them groupers, wrasses and eels. | A wide range of predators prey on this species including many fishes such as serranid groupers, wrasses and eels, as well as sharks |
| A female lays 100,000 to 500,000 eggs in strings cemented to her den roof | They produce between 100 000 and 500 000 eggs, which are bound together in strings (festoons) and cemented to the roof of the den. (note: 100 000 to 500 000 in the source) |
| then stays, stroking and ventilating them | The female then remains with the eggs, constantly ventilating and stroking the eggs |
| She usually goes without food, burns her own muscle for energy and can shed a third or more of her body weight. | She typically does not feed during this entire period ... the female digests her own musculature as an energy source and can lose a third or more of her body weight. |
| When the hatchlings emerge she weakens and dies. | As the hatchlings emerge, the female weakens and dies. |
| In cool waters the brooding can take up to 4 to 5 months. | which can take up to 4 - 5 months in cool waters |
| The hatchlings, called paralarvae, are 1 to 2 mm long and transparent. | Hatchlings emerge at around 1 - 2 mm in length ... The hatchlings are known as paralarvae and are transparent |
| They swim straight into open water, where the FAO catalogue says the planktonic (drifting) phase is estimated at weeks to months, depending on temperature and conditions. | immediately swim into the water column to commence a planktonic phase ... estimated to be in the order of weeks to months, again dependent on the temperature and other environmental conditions |
| On settling, the young change into a form closer to the adults. | On settlement, juveniles metamorphose into a form more typical of the adults |
| the FAO catalogue puts the biggest at around 1.8 m in total length and over 20 kg, with a mantle (body sac) of up to 400 mm | * Based on Mediterranean and north - east Atlantic material (see Remarks above). Size: Mantle length to 400 mm; total length to around 1.8 m; body weight to over 20 kg. (note: faq) |
| The FAO catalogue says shelled prey are typically extracted by drilling: toothed salivary papillae bore through the shell to paralyse or relax the mollusc inside. | The latter group typically are extracted by drilling through the shell with the toothed salivary papillae to paralyse/relax the occupant (note: faq) |
| The FAO catalogue estimates its longevity at one to two years | Longevity of this species has been estimated in the range of one to two years. (note: faq; the claim says estimated) |
| every female dies after a single brooding of her eggs | All females die after a single brooding event. (note: faq) |
| It is commonly found smaller, with a 250 mm mantle. | Common at smaller size (250 mm ML). Geographical Distribution : Mediterranean Sea (note: faq) |
| Long Arms, Short Life | Arms long (4 to 5.5 times mantle length) (note: heading; "Short Life" rests on the longevity claim (estimated one to two years) in the same section) |
| Night Shift on the Seabed | This species is primarily night active, typically spending daylight hours within a den. (note: heading) |
| One Brood, Then the End | All females die after a single brooding event. (note: heading; the section is about the female) |
| A mother's last job | As the hatchlings emerge, the female weakens and dies. (note: blockquote lead) |

## Fiorito & Scotto (1992). Observational Learning in Octopus vulgaris. Science.

https://doi.org/10.1126/science.256.5056.545

| The page says | The source says |
| :--- | :--- |
| It can learn by watching. | These results show that observational learning can occur in invertebrates. |
| In a 1992 experiment, untrained octopuses watched trained ones pick one of two objects that differed only in colour. | Untrained Octopus vulgaris (observers) were allowed to watch conditioned Octopus(demonstrators) perform the task of selecting one of two objects that were presented simultaneously and differed only in color. |
| Tested alone afterwards, the watchers consistently chose the same object as the trained animals had | After being placed in isolation, the observers, in a similar test, consistently selected the same object as did the demonstrators. |
| they learned faster than the trained animals did during their own conditioning | was more rapid than the learning that occurred during the conditioning of animals |
| tags: intelligent | These results show that observational learning can occur in invertebrates. (note: tagMetadata: learned behaviour; the elephant's tag rests on a learned task the same way) |