The head and mantle are only slightly separated, so the bulb that looks like a big head is mostly the mantle, which holds the organs. The arms meet in a ring with the mouth and its beak at the center, and in a typical octopus a web of skin joins the arms at their bases.
- True of
- all octopuses; the web as described for the typical octopus
- Corrects
- The big rounded part is not the head: it is the mantle, the body sac behind the head.
- First fold
- Fold 1
3 sources
- Encyclopaedia Britannica Octopus encyclopedia
- Encyclopaedia Britannica Cephalopod encyclopedia
- National Geographic Octopuses, facts and information news
Two branchial hearts, one at the base of each gill, push blood through the gills, where it picks up oxygen. The third, the systemic heart, then pumps that oxygen-rich blood around the rest of the body. The two branchial hearts are smaller than the systemic heart, which is the largest and most muscular of the three.
- True of
- all octopuses
- First fold
- Fold 1
4 sources
- Encyclopaedia Britannica How Many Hearts Does an Octopus Have? encyclopedia
- Encyclopaedia Britannica Cephalopod encyclopedia
- Natural History Museum, London Octopuses keep surprising us - here are eight examples how museum
- Live Science How many hearts does an octopus have? news, 2023
Muscle does the work a skeleton does in other animals: the body and arms keep their shape and move by muscle alone. A few firm parts remain: the hard beak, a case of cartilage around the brain, and in many octopuses two small internal rods where head muscles anchor, all that is left of an ancestral shell.
- True of
- all octopuses
- Corrects
- Boneless does not mean without any firm parts: the beak is hard and the brain sits in a cartilage case.
- First fold
- Fold 1
3 sources
- Monterey Bay Aquarium Giant Pacific octopus aquarium
- Encyclopaedia Britannica Cephalopod encyclopedia
- Field Museum Cephalopods to Wrap Your Head Around museum
With no bones, the rest of the body can flatten and stretch to follow the beak through an opening, so aquarium keepers work on the rule that if the beak fits, the octopus fits. A fully grown giant Pacific octopus can get through a hole about the size of a lemon.
- True of
- all octopuses
- Must keep
than its beak
- First fold
- Fold 1
3 sources
- National Geographic Common Octopus news
- Seattle Aquarium Giant Pacific octopus aquarium
- CBC News Octopus makes daring escape from aquarium to Pacific Ocean news, 2016
An octopus has no bones, so its soft body can flatten and stretch through openings far smaller than it looks. Only the hard beak sets the limit: aquarium keepers work on the rule that if the beak fits, the octopus fits.
- True of
- all octopuses
- Must keep
can
- First fold
- Fold 1
3 sources
- National Geographic Common Octopus news
- Seattle Aquarium Giant Pacific octopus aquarium
- CBC News Octopus makes daring escape from aquarium to Pacific Ocean news, 2016
Zoologists use the two words for different limbs. All eight of an octopus's suckered limbs are arms, while squid and cuttlefish add a separate pair of tentacles to their eight arms. Calling octopus arms tentacles is a common slip.
- True of
- all octopuses; squid and cuttlefish for the comparison
- Corrects
- Octopus limbs are often called tentacles; they are arms.
- First fold
- Fold 1
2 sources
- Encyclopaedia Britannica Cephalopod encyclopedia
- National Geographic Octopuses, facts and information news
The parrot-like beak sits at the center of the ring of arms and bites into prey. In squid beaks, the best-studied kind, chitin is toughened with proteins and stiffens gradually from a soft base to a very hard tip, with no minerals at all. The radula behind the beak carries tiny teeth, but nothing else in the body is as big and rigid.
- True of
- all octopuses; beak chemistry measured in detail in the Humboldt squid
- Must keep
hard part
- First fold
- Fold 3
3 sources
- National Geographic Common Octopus news
- Seattle Aquarium Giant Pacific octopus aquarium
- Science (author manuscript, PubMed Central) The Transition from Stiff to Compliant Materials in Squid Beaks journal, 2008
The wound starts closing within hours, and a bud of unspecialized cells forms at the stump and grows out, rebuilding muscle, nerves and suckers into a working arm over the following months. An octopus can lose an arm to a predator and grow it back without lasting harm.
- True of
- octopuses (studied mostly in the common octopus, Octopus vulgaris)
- First fold
- Fold 3
3 sources
- Zoological Letters (PubMed record) Mechanisms of wound closure following acute arm injury in Octopus vulgaris journal, 2016
- National Geographic Common Octopus news
- Mental Floss On a Limb: How an Octopus Regrows Its Arms news, 2021
The suckers run in two rows along each arm. Counts are specific to species and sex, so this figure should not be given for octopuses in general.
- True of
- giant Pacific octopus (Enteroctopus dofleini), adults
- Must keep
about
- Numbers
- about 2,240 suckers on an adult female giant Pacific octopus
- about 100 fewer than a female suckers on an adult male giant Pacific octopusAlaska Dept. of Fish and Game gives 2,140 to 2,240 for adults
- First fold
- Fold 3
3 sources
- Monterey Bay Aquarium Giant Pacific octopus aquarium
- Alaska Department of Fish and Game Giant Pacific Octopus (Enteroctopus dofleini) Species Profile government
- Encyclopaedia Britannica Octopus encyclopedia
Our blood carries oxygen on iron-based hemoglobin; an octopus uses hemocyanin, which is not held inside cells but dissolved in the blood plasma. The copper is what gives oxygen-rich octopus blood its blue color, and blood that has lost its oxygen turns almost clear.
- True of
- all octopuses
- Must keep
oxygen
- Corrects
- Octopus blood is not blue all the time: without oxygen it is nearly colorless.
- First fold
- Fold 4
3 sources
- Encyclopaedia Britannica Cephalopod encyclopedia
- Natural History Museum, London Octopuses keep surprising us - here are eight examples how museum
- Frontiers in Zoology (PubMed record) Blue blood on ice: modulated blood oxygen transport facilitates cold compensation and eurythermy in an Antarctic octopod journal, 2015
A hard jet raises the pressure inside the mantle above anything the veins can push against, so blood stops flowing back to the hearts, and the systemic heart, which beats only when it fills, stalls. Octopuses can run up only a small oxygen debt, so the researchers who measured this concluded that jet-propelled travel is impossible for more than a few meters. Everyday movement is crawling on the arms.
- True of
- common octopus (Octopus vulgaris), measured in freely moving animals
- Must keep
jet
- First fold
- Fold 4
3 sources
- Journal of Experimental Biology (Internet Archive copy of the PDF) Blood flow and pressure changes in exercising octopuses (Octopus vulgaris) journal, 1987
- Smithsonian Magazine Ten Wild Facts About Octopuses: They Have Three Hearts, Big Brains and Blue Blood news
- Encyclopaedia Britannica Octopus encyclopedia
Water drawn into the mantle cavity bathes the gills and leaves through the siphon. When the mantle squeezes hard, the same tube works as a nozzle, and because it can be turned in different directions the octopus chooses which way the jet pushes it. Ink also leaves the body through the siphon.
- True of
- all octopuses
- First fold
- Fold 4
3 sources
- Encyclopaedia Britannica Octopus encyclopedia
- Encyclopaedia Britannica Cephalopod encyclopedia
- Monterey Bay Aquarium Giant Pacific octopus aquarium
The mantle's steady squeezing and relaxing pumps seawater through the cavity, and oxygen passes from the water into the blood as it flows through the gills. Each gill has its own branchial heart at its base to push blood through it.
- True of
- all octopuses
- First fold
- Fold 4
2 sources
- Encyclopaedia Britannica Cephalopod encyclopedia
- Encyclopaedia Britannica How Many Hearts Does an Octopus Have? encyclopedia
The mantle wraps the gut, hearts and other organs. Its underside is open to form the mantle cavity, which the octopus fills with water and then squeezes out through the siphon, both to breathe and, with a hard squeeze, to jet.
- True of
- all octopuses
- First fold
- Fold 4
2 sources
- Encyclopaedia Britannica Cephalopod encyclopedia
- Monterey Bay Aquarium Giant Pacific octopus aquarium
In an open system, such as a snail's or a clam's, the heart pumps blood into a body cavity where it washes loosely around the organs. A closed system keeps blood in arteries, capillaries and veins, so it can be pushed under pressure to where it is needed, which suits an active predator. The octopus's three hearts drive that closed loop.
- True of
- octopuses, squid and cuttlefish (coleoid cephalopods)
- First fold
- Fold 5
3 sources
- Encyclopaedia Britannica Cephalopod encyclopedia
- LibreTexts Biology Reading: Mollusks university
- Lumen Learning (SUNY Biology II) Overview of the Circulatory System book
Muscle is mostly water and barely changes volume, so when one set of fibers makes the arm thinner, the arm has to get longer. By working transverse, longitudinal and oblique muscles against one another, an octopus can bend, shorten, lengthen or twist an arm at any point along it.
- True of
- octopus arms
- First fold
- Fold 5
2 sources
- Frontiers in Cell and Developmental Biology The Musculature of Coleoid Cephalopod Arms and Tentacles journal, 2016
- Florida Atlantic University The ultimate multi-taskers: how octopuses use their 8 arms university
Most mollusks other than clams and their relatives have a radula; snails use theirs to rasp food. An octopus uses its radula to scrape flesh and, after its saliva has softened a shell, to rasp a small hole through it. Teeth worn away at the front are replaced by new rows growing from behind.
- True of
- most octopuses (reduced or missing in some deep-sea finned octopods)
- First fold
- Fold 5
3 sources
- Encyclopaedia Britannica Radula encyclopedia
- Encyclopaedia Britannica Octopus encyclopedia
- Monterey Bay Aquarium Giant Pacific octopus aquarium
A gland in the ink sac makes the ink, which gets its dark color from melanin; as it is released it mixes with mucus from a gland in the funnel. Some deep-sea octopuses have no ink sac at all.
- True of
- most octopuses (absent in some deep-sea species)
- Must keep
most
- First fold
- Fold 5
3 sources
- Encyclopaedia Britannica Octopus encyclopedia
- Encyclopaedia Britannica Cephalopod encyclopedia
- Marine Drugs (PubMed Central) Cephalopod Ink: Production, Chemistry, Functions and Applications journal, 2014
Sensory cells in the suckers detect chemicals as well as touch, so an arm can tell what it is holding without the octopus seeing it. A 2020 study in the California two-spot octopus found a family of chemotactile receptors, found only in cephalopods, that respond to poorly soluble chemicals on the surfaces of prey and other animals.
- True of
- octopuses; the receptor family was identified in the California two-spot octopus (Octopus bimaculoides)
- First fold
- Fold 1
3 sources
- Cell (PubMed record) Molecular Basis of Chemotactile Sensation in Octopus journal, 2020
- Harvard University, Department of Molecular and Cellular Biology Investigating How the Octopus 'Tastes' by Touch [Bellono Lab] university, 2020
- Monterey Bay Aquarium Giant Pacific octopus aquarium
The slit lines up with a horizontal band of densely packed light-sensitive cells across the retina, and the pupil reacts quickly when the light changes. Signals from the balance organs turn the eyes to keep them level as the body tilts, so the slit stays horizontal.
- True of
- common octopus (Octopus vulgaris)
- First fold
- Fold 4
3 sources
- Frontiers in Physiology (PubMed Central) The Eye of the Common Octopus (Octopus vulgaris) journal, 2020
- Frontiers in Physiology (PubMed record) The Pupillary Response of the Common Octopus (Octopus vulgaris) journal, 2020
- Current Biology (author manuscript, PubMed Central) The neural basis of visual processing and behavior in cephalopods journal, 2023
Like our eyes, an octopus eye has a lens that focuses an image onto a retina. But its light-sensitive cells face the incoming light and send their fibers straight out of the back of the eye to the brain, so no nerve bundle has to pass through the retina; in our eyes, that crossing point is the blind spot. The last common ancestor of octopuses and vertebrates had no such eye, so the two designs arose independently.
- True of
- octopuses (shared with squid and cuttlefish)
- First fold
- Fold 5
3 sources
- Current Biology (author manuscript, PubMed Central) The neural basis of visual processing and behavior in cephalopods journal, 2023
- Glaucoma UK Why is a squid eye "better evolved" than a human eye? ngo, 2023
- Frontiers in Physiology (PubMed Central) The Eye of the Common Octopus (Octopus vulgaris) journal, 2020
That sits oddly with how well octopuses match colored backgrounds, and scientists are still testing explanations, including reflective skin cells that take on the color of the surrounding light, light-sensitive proteins in the skin, and a 2016 proposal that their off-center pupils could recover color from the way different colors blur. The one-pigment finding is solid; whether octopuses get color information some other way is still open.
- True of
- most octopuses (a few deep-sea cephalopods have more than one visual pigment)
- Must keep
probably
- Corrects
- It is not proven beyond doubt either way: say octopuses are probably color-blind, not that they definitely are or that they see in color.
- First fold
- Fold 5
3 sources
- Current Biology (author manuscript, PubMed Central) The neural basis of visual processing and behavior in cephalopods journal, 2023
- PNAS (PubMed record) Spectral discrimination in color blind animals via chromatic aberration and pupil shape journal, 2016
- Monterey Bay Aquarium Giant Pacific octopus aquarium
The light-catching parts of their photoreceptors are lined up in two directions at right angles, so the eye can compare horizontally and vertically polarized light. Trained octopuses pick out patterns made only of differences in polarization, and this sense may help them spot transparent objects and see contrast in murky water.
- True of
- octopuses (shared with squid and cuttlefish)
- First fold
- Fold 5
3 sources
- Journal of Experimental Biology (PubMed record) Polarization contrast vision in Octopus journal, 1996
- Journal of Experimental Biology (PubMed record) Thresholds of polarization vision in octopuses journal, 2021
- Current Biology (author manuscript, PubMed Central) The neural basis of visual processing and behavior in cephalopods journal, 2023
Inside each statocyst a small dense mass rests on the sensory hairs and shifts as the animal tilts or moves, bending different hairs. Signals from the statocysts drive eye movements that keep the eyes level when the head turns, and damaging them makes octopuses worse at telling shapes apart.
- True of
- all octopuses
- First fold
- Fold 5
3 sources
- Encyclopaedia Britannica Cephalopod encyclopedia
- Encyclopaedia Britannica Statocyst encyclopedia
- Current Biology (author manuscript, PubMed Central) The neural basis of visual processing and behavior in cephalopods journal, 2023
Researchers found that light makes chromatophores expand in isolated pieces of skin, fastest under blue light, and that sensory cells in the skin carry the same light-detecting protein, opsin, that the eyes use. Scientists do not yet know how, or how much, the living animal uses this skin sense.
- True of
- California two-spot octopus (Octopus bimaculoides)
- Must keep
two-spot
- Corrects
- Light-sensitive skin is not the same as seeing with the skin; there is no evidence the skin forms images.
- First fold
- Fold 6 (not for young readers)
3 sources
- Journal of Experimental Biology (PubMed record) Eye-independent, light-activated chromatophore expansion (LACE) and expression of phototransduction genes in the skin of Octopus bimaculoides journal, 2015
- Current Biology (author manuscript, PubMed Central) The neural basis of visual processing and behavior in cephalopods journal, 2023
- National Geographic Adaptive Colour-Changing Sheet Inspired By Octopus Skin news, 2014
That is about as many neurons as a dog, but where a dog's are mostly in its brain, most of an octopus's run down the nerve cords of its arms, which handle much of the sensing and movement locally. The rest are in the brain in the head.
- True of
- common octopus (Octopus vulgaris)
- Must keep
about
roughly two-thirds
- Numbers
- about 500 million neurons in the common octopusclassic estimate from J. Z. Young's counts in the 1960s
- about two-thirds share of those neurons outside the brain, mostly in the arms
- First fold
- Fold 4
3 sources
- Natural History Museum, London Octopuses keep surprising us - here are eight examples how museum
- Frontiers in Physiology Embodied Organization of Octopus vulgaris Morphology, Vision, and Locomotion journal, 2017
- ScienceDaily (Okinawa Institute of Science and Technology release) Do octopuses' arms have a mind of their own? news, 2020
The brain is a set of nerve lobes fused together around the food tube that runs from the mouth to the stomach. Because food travels through it, a sharp piece of swallowed prey can injure the brain.
- True of
- all octopuses (shared with other cephalopods)
- First fold
- Fold 4
3 sources
- Natural History Museum, London Octopuses keep surprising us - here are eight examples how museum
- Field Museum Cephalopods to Wrap Your Head Around museum
- Current Biology (author manuscript, PubMed Central) The neural basis of visual processing and behavior in cephalopods journal, 2023
Its brain-to-body ratio is also higher than that of many vertebrates, though not mammals. The ratio is only a rough guide to intelligence, but it shows how much an animal invests in its brain.
- True of
- octopuses
- Must keep
size
- First fold
- Fold 4
3 sources
- Natural History Museum, London Octopuses keep surprising us - here are eight examples how museum
- Current Biology (author manuscript, PubMed Central) The neural basis of visual processing and behavior in cephalopods journal, 2023
- Encyclopaedia Britannica Cephalopod encyclopedia
This shows the program for reaching is built into the arm's nerve circuitry, so the brain can send a simple go signal and leave the details to the arm. The arms are not independent, though. Octopuses can learn to steer a single arm to food by sight, and a 2020 study showed arms passing sensory information back to the brain, which does the learning.
- True of
- common octopus (Octopus vulgaris)
- Must keep
some
- Corrects
- Arms that run their own movements are not arms with their own minds: the central brain still steers them and learns from them.
- First fold
- Fold 5 (not for young readers)
3 sources
- Science (PubMed record) Control of octopus arm extension by a peripheral motor program journal, 2001
- Natural History Museum, London Octopuses keep surprising us - here are eight examples how museum
- ScienceDaily (Okinawa Institute of Science and Technology release) Do octopuses' arms have a mind of their own? news, 2020
The octopus retina contains almost nothing but light-sensitive cells, which send their signals straight to the optic lobes. Much of the image processing that our retinas do therefore happens inside the octopus's brain instead.
- True of
- octopuses (shared with squid and cuttlefish)
- Must keep
most of
- First fold
- Fold 5
2 sources
- Current Biology (author manuscript, PubMed Central) The neural basis of visual processing and behavior in cephalopods journal, 2023
- Natural History Museum, London Octopuses keep surprising us - here are eight examples how museum
RNA editing swaps single letters in a gene's message after it is copied from DNA, so one gene can yield slightly different proteins. When researchers cooled the water of California two-spot octopuses, editing changed at more than 13,000 sites in their nervous systems, altering proteins used in nerve signaling. Scientists are still finding out how much this flexibility matters to the living animal.
- True of
- octopuses, squid and cuttlefish (coleoid cephalopods); temperature study in Octopus bimaculoides
- Must keep
still finding out
- Numbers
- more than 13,000 sites where RNA editing changed after cooling, California two-spot octopus
- First fold
- Fold 6
3 sources
- Cell (PubMed record) Trade-off between Transcriptome Plasticity and Genome Evolution in Cephalopods journal, 2017
- Cell (PubMed record) Temperature-dependent RNA editing in octopus extensively recodes the neural proteome journal, 2023
- Marine Biological Laboratory Masters of Acclimation: Octopuses Adjust to Cold by Editing their RNA university, 2023
Each papilla is a patch of skin with muscle fibers running in rings and in lines radiating outwards. Tightening them pushes the skin up into a bump or point, and relaxing them lets it lie flat again, a little like goosebumps.
- True of
- octopuses
- First fold
- Fold 3
3 sources
- Two Oceans Aquarium Foundation How does an octopus change its colour and shape? aquarium
- Natural History Museum, London Octopuses keep surprising us - here are eight examples how museum
- Seattle Aquarium Giant Pacific octopus aquarium
Each chromatophore is a small organ rather than a single cell: a pigment sac ringed by radial muscles, each muscle wired to nerves from the brain. When the muscles contract the sac is stretched wide and its red, yellow, brown or black pigment shows; when they relax, the elastic sac shrinks back to a dot. In the usual layering, iridophores lie just beneath the chromatophores and reflect light as shimmering blues and greens, and leucophores lie deepest, scattering white light as a bright backdrop.
- True of
- octopuses (shared with other cephalopods)
- First fold
- Fold 4
3 sources
- Biological Reviews (PubMed record) Cephalopod chromatophores: neurobiology and natural history journal, 2001
- National Geographic Adaptive Colour-Changing Sheet Inspired By Octopus Skin news, 2014
- Journal of the Royal Society Interface (PubMed Central) Mechanisms and behavioural functions of structural coloration in cephalopods journal, 2009
An octopus can go pale, dark, blotchy or striped to match what is around it, which hides it from predators and from the animals it hunts. The day octopus, for example, can flash orange, red and brown along corals. The same skill works the other way too: color changes can show mood or intent, warn off a rival or startle an attacker. The giant Pacific octopus, for example, changes color in ways that show its mood and intentions.
- True of
- most octopuses
- Must keep
can
- First fold
- Fold 1
3 sources
- National Geographic These are the weird and wonderful reasons octopuses change shape and color news, 2024
- Seattle Aquarium Giant Pacific octopus aquarium
- Encyclopaedia Britannica Cephalopod encyclopedia
Octopus color change is quicker than the blink of an eye. It can be this fast because each chromatophore (color sac) in the skin is wired to nerves from the brain, so the brain can switch patterns almost at once.
- True of
- octopuses (fastest figures reported for giant Pacific octopus and from octopus researchers)
- Must keep
can
- Numbers
- about one tenth of a second (100 milliseconds) time for the fastest color changesLive Science quotes researcher Leila Deravi: the fastest transitions are under 100 ms; Britannica: the giant Pacific octopus can reportedly change color in one-tenth of a second
- First fold
- Fold 3
3 sources
- Live Science How do octopuses change color? news, 2022
- Encyclopaedia Britannica Octopus encyclopedia
- Vision (via PubMed Central) The Colours of Octopus: Using Spectral Data to Measure Octopus Camouflage journal, 2022
Small muscles under the skin push up soft bumps called papillae, so a smooth octopus can turn lumpy or spiky in moments. Paired with a color change, this lets an octopus look like part of the seabed instead of an animal sitting on it. The day octopus, which hunts in daylight, can turn its skin into long lumpy ridges that mimic nearby corals, rocks or algae.
- True of
- most octopuses; day octopus (Octopus cyanea) as a well-documented example
- Must keep
can
- First fold
- Fold 3
3 sources
- Encyclopaedia Britannica Cephalopod encyclopedia
- Cornell Chronicle (Cornell University) Octopus inspires 3-D texture morphing project university, 2017
- Monterey Bay Aquarium Day octopus aquarium
Instead of hiding, this long-armed octopus forages over open sand in daylight. Scientists filming it in Sulawesi and Bali saw it swim flat like a banded sole, trail its banded arms like the spines of a lionfish, and hide six arms in a hole while waving two banded arms like a sea snake. Several of the animals it copies are venomous or toxic, so looking like them may keep fish predators away.
- True of
- mimic octopus (Thaumoctopus mimicus) only, Indo-Malayan region
- Must keep
can
- First fold
- Fold 3
3 sources
- Proceedings of the Royal Society B (author copy, White Rose Research Online) Dynamic mimicry in an Indo-Malayan octopus journal, 2001
- American Museum of Natural History The Talented Mimic Octopus museum, 2015
- Smithsonian Magazine The Mimic Octopus news, 2010
Uniform and mottle patterns work by matching the background, such as plain sand or speckled gravel. Disruptive patterns use strong contrasting patches so a predator does not see the octopus's outline as one animal. Researchers use the same three groups to describe camouflage in octopuses and cuttlefish.
- True of
- octopuses and other cephalopods (studied in Octopus cyanea, Octopus vulgaris and cuttlefish)
- First fold
- Fold 5
2 sources
- PLoS ONE (via PubMed Central) Camouflaging in a Complex Environment—Octopuses Use Specific Features of Their Surroundings for Background Matching journal, 2012
- Proceedings of the Royal Society B (via PubMed Central) Cuttlefish dynamic camouflage: responses to substrate choice and integration of multiple visual cues journal, 2009
Filming wild gloomy octopuses at a crowded site in Jervis Bay, researchers found that when an approaching dark octopus was met by an equally dark one, the encounter was more likely to turn into grappling, while a paler octopus facing a dark one tended to retreat. Octopuses also stood tall on high ground with their web spread. It was the first study to show octopuses using signals systematically in contests.
- True of
- gloomy octopus (Octopus tetricus), one site in Jervis Bay, Australia
- Must keep
usually
- First fold
- Fold 5
2 sources
- Current Biology (via PubMed) Signal Use by Octopuses in Agonistic Interactions journal, 2016
- The University of Sydney Octopuses shed their asocial reputation university, 2016
The dark band sweeps out from the head over the body and arms and then fades, and it has been filmed in several species, including the common octopus, the day octopus and Octopus laqueus. Scientists are still testing what it is for: one idea is that it makes a still octopus look as if it is moving, tricking prey into leaving its hiding spot.
- True of
- some octopus species, including common octopus (Octopus vulgaris) and day octopus (Octopus cyanea)
- Must keep
some
scientists are still finding out
- First fold
- Fold 5
2 sources
- Frontiers in Physiology (via PubMed Central) Dynamic Skin Patterns in Cephalopods journal, 2017
- National Geographic These are the weird and wonderful reasons octopuses change shape and color news, 2024
The ink is made in an ink sac inside the body and is mostly dark melanin pigment mixed with mucus; it leaves through the siphon, usually as the octopus jets off. Octopuses often pale, ink and jet all at once, so the attacker is left facing a dark cloud while a hard-to-see octopus shoots away. A few octopuses, mainly deep-sea finned species, have little or no ink.
- True of
- most octopuses (deep-sea finned octopuses and a few shallow-water species have little or no ink)
- Must keep
can
- First fold
- Fold 1
3 sources
- Marine Drugs (via PubMed Central) Cephalopod Ink: Production, Chemistry, Functions and Applications journal, 2014
- Monterey Bay Aquarium Giant Pacific octopus aquarium
- Pacific Science (University of Hawai'i ScholarSpace) An Observation of Inking Behavior Protecting Adult Octopus bocki from Predation by Green Turtle (Chelonia mydas) Hatchlings journal, 2005
Water drawn into the muscular mantle is squeezed out through the narrow siphon, pushing the octopus the other way; it usually travels with its rounded mantle in front, so it can look as if it swims backwards. Octopuses can point the siphon to steer. Most of the time they crawl on their arms and save jetting for a quick escape.
- True of
- most octopuses
- Must keep
can
- First fold
- Fold 1
3 sources
- Monterey Bay Aquarium Giant Pacific octopus aquarium
- Science Friday Jet Propulsion Locomotion Of Squid And Octopus news, 2015
- Encyclopaedia Britannica Cephalopod encyclopedia
A survey of 38 scientists and aquarists who had kept 25 octopus species found that the tendency to escape depends on the species. Many aquariums have stories of octopuses leaving their tanks, even visiting neighboring tanks for food at night. Escaping is dangerous for an octopus, so the study also gave keepers ways to keep octopuses safely in their tanks.
- True of
- octopuses in captivity; how often varies by species
- Must keep
can
- First fold
- Fold 3
2 sources
- Journal of Applied Animal Welfare Science (via PubMed) Interspecific evaluation of octopus escape behavior journal, 2004
- The Guardian Alien intelligence: the extraordinary minds of octopuses and other cephalopods news, 2017
Scientists call such a blob a pseudomorph, meaning "false body". How much mucus is mixed in changes the result, from a spreading cloud to a blob that hangs in the water. In one small test, green turtle hatchlings chasing Bock's pygmy octopus snapped at the ink blobs, then gave up the chase while the octopus escaped.
- True of
- some octopuses (seen in Bock's pygmy octopus, Octopus bocki) and many squid
- Must keep
some
- First fold
- Fold 4
3 sources
- Pacific Science (University of Hawai'i ScholarSpace) An Observation of Inking Behavior Protecting Adult Octopus bocki from Predation by Green Turtle (Chelonia mydas) Hatchlings journal, 2005
- Marine Drugs (via PubMed Central) Cephalopod Ink: Production, Chemistry, Functions and Applications journal, 2014
- Australian Museum Squid museum
Camouflage only works until a predator spots the octopus. Then a sudden change to a high-contrast or much darker look, with the body stretched tall and wide, can make a predator hesitate long enough for the octopus to jet away. Scientists call this a deimatic (startle) display; in cephalopods such alarm patterns use strong light-and-dark contrast, dark outlines or eye-like spots.
- True of
- many octopus species
- Must keep
may
- First fold
- Fold 4
2 sources
- National Geographic These are the weird and wonderful reasons octopuses change shape and color news, 2024
- Encyclopaedia Britannica Cephalopod encyclopedia
The veined (coconut) octopus wraps six arms tightly around its body so it looks like a coconut tiptoeing along, and the algae octopus holds its arms like drifting seaweed, while the two back arms roll along the sand like tank treads. Each arm stays on the sand for more than half of each stride, so scientists count it as true walking. Walking in disguise lets the octopus move away from danger while staying hidden.
- True of
- veined octopus (Amphioctopus marginatus) and algae octopus (Abdopus aculeatus) only
- Must keep
can
- First fold
- Fold 4
2 sources
- Science (via PubMed) Underwater bipedal locomotion by octopuses in disguise journal, 2005
- UC Berkeley News Octopuses occasionally stroll around on two arms, UC Berkeley biologists report university, 2005
Crabs are a favorite of many octopuses; the giant Pacific octopus also eats clams, scallops, abalone, fish and even other octopuses. An octopus often carries its catch back to its den to eat. A few kinds of octopus feed on plankton, tiny drifting animals, instead.
- True of
- most octopuses; diet varies by species and place
- First fold
- Fold 1
3 sources
- Monterey Bay Aquarium Giant Pacific octopus aquarium
- Seattle Aquarium Giant Pacific octopus aquarium
- Encyclopaedia Britannica Octopus encyclopedia
Octopuses can also pull shells apart or bite them open, but prey that is hard to open is drilled. Saliva softens the shell, and the octopus scrapes a small hole with a rough, toothy tongue called the radula and a small drilling organ called the salivary papilla. Saliva sent through the hole then loosens the animal inside.
- True of
- many octopuses, well studied in the common octopus (Octopus vulgaris) and giant Pacific octopus
- Must keep
can
- First fold
- Fold 3
3 sources
- Monterey Bay Aquarium Giant Pacific octopus aquarium
- Vita Malacologica (Naturalis Biodiversity Center repository) Recognizing cephalopod boreholes in shells and the northward spread of Octopus vulgaris Cuvier, 1797 journal, 2015
- Frontiers in Physiology (via PubMed Central) Cephalopods as Predators: A Short Journey among Behavioral Flexibilities, Adaptions, and Feeding Habits journal, 2017
A hunting day octopus may pounce every meter or two, covering a rock, a clump of seaweed or a patch of seabed with its web, then pausing a few seconds to feel underneath before moving on. Aquarium staff describe a giant Pacific octopus billowing out like a parachute to envelop a crab.
- True of
- some octopuses, including the day octopus (Octopus cyanea) and giant Pacific octopus
- Must keep
some
- First fold
- Fold 4
2 sources
- Frontiers in Physiology (via PubMed Central) Cephalopods as Predators: A Short Journey among Behavioral Flexibilities, Adaptions, and Feeding Habits journal, 2017
- NOAA Ocean Today How to Feed a Giant Octopus government, 2011
Fish such as the blue goatfish scout crevices and show the octopus where prey is hiding, while the octopus decides whether and when the group moves on. Sometimes the octopus punches a fish, which is then pushed to the edge of the group or leaves. Only a few hunts have been filmed (eight punches in the first study, 13 hunting scenes in the second), so scientists are still finding out how common this is and why octopuses punch.
- True of
- day octopus (Octopus cyanea), Red Sea (Israel and Egypt)
- Must keep
sometimes
scientists are still finding out
- First fold
- Fold 4
3 sources
- Smithsonian Magazine Watch Octopuses Sucker-Punch Fish news, 2020
- Nature Ecology & Evolution (via PubMed) Multidimensional social influence drives leadership and composition-dependent success in octopus-fish hunting groups journal, 2024
- Smithsonian Magazine Watch Octopuses Team Up With Fish to Hunt—and Punch Those That Don't Contribute news, 2024
Toxins and enzymes from the salivary glands paralyze a crab or clam and begin dissolving its tissues, so the meat comes away from the shell more easily. Fry and colleagues (2009) found the venom proteins share a single early origin across octopuses, cuttlefish and some squid. Of all octopuses, only the blue-ringed octopuses are known to be dangerous to people.
- True of
- all octopuses (and cuttlefish and some squid), according to venom-gland studies
- First fold
- Fold 5 (not for young readers)
3 sources
- National Geographic All Octopuses Are Venomous, Study Says news, 2009
- Journal of Molecular Evolution (via PubMed) Tentacles of venom: toxic protein convergence in the Kingdom Animalia journal, 2009
- Monterey Bay Aquarium Giant Pacific octopus aquarium
In a 1990 lab study in Naples, common octopuses learned to pull the plug out of a glass jar holding a live crab, and got faster with practice. In captivity octopuses have also learned to open screw-top jars, and aquariums describe their giant Pacific octopuses learning to open jars and solve puzzles.
- True of
- octopuses in captivity: common octopus (Octopus vulgaris) in a lab study; giant Pacific and other octopuses in aquariums
- Must keep
can
- First fold
- Fold 3
3 sources
- Behavioral and Neural Biology (via PubMed) Problem solving ability of Octopus vulgaris Lamarck (Mollusca, Cephalopoda) journal, 1990
- The Guardian Alien intelligence: the extraordinary minds of octopuses and other cephalopods news, 2017
- Monterey Bay Aquarium Giant Pacific octopus aquarium
Over two weeks, eight octopuses were visited separately by both people, who wore the same aquarium T-shirt. By the end the octopuses reacted differently to each person: reaching towards or away, where they pointed their siphon, and whether they showed a dark bar across the eye. The researchers did not work out which cues the octopuses used, and the study does not show that octopuses recognize faces.
- True of
- giant Pacific octopus (Enteroctopus dofleini), one study of 8 captive animals at the Seattle Aquarium
- First fold
- Fold 3
3 sources
- Journal of Applied Animal Welfare Science (via PubMed) Octopuses (Enteroctopus dofleini) recognize individual humans journal, 2010
- American Psychological Association (Speaking of Psychology podcast) Inside the mind of an octopus ngo
- The Guardian Alien intelligence: the extraordinary minds of octopuses and other cephalopods news, 2017
Much of this work was done with common octopuses at the zoological station in Naples, where octopuses learned to tell apart shapes that meant a reward from shapes that did not, and worked through maze tasks. Aquariums also report octopuses solving mazes and puzzles.
- True of
- octopuses in lab studies, mainly the common octopus (Octopus vulgaris)
- Must keep
can
- First fold
- Fold 4
3 sources
- Encyclopaedia Britannica Cephalopod encyclopedia
- The Guardian Alien intelligence: the extraordinary minds of octopuses and other cephalopods news, 2017
- Monterey Bay Aquarium Giant Pacific octopus exhibit aquarium
Eight giant Pacific octopuses were each given only a floating pill bottle; after exploring it, two repeatedly aimed water jets to send it to the far end of the tank, where the circulating water carried it back to them. In another study, nine of fourteen common octopuses given Lego objects showed play-like handling after a few days of exploring them. Scientists say "play-like" because they cannot ask an octopus whether it is having fun.
- True of
- giant Pacific octopus and common octopus in lab and aquarium experiments
- Must keep
play-like
- First fold
- Fold 4
3 sources
- Journal of Comparative Psychology (APA PsycNet) Exploration, play and habituation in octopuses (Octopus dofleini) journal, 1999
- Journal of Comparative Psychology (via PubMed) When do octopuses play? Effects of repeated testing, object type, age, and food deprivation on object play in Octopus vulgaris journal, 2006
- American Psychological Association (Speaking of Psychology podcast) Inside the mind of an octopus ngo
In quiet sleep the octopus is pale and still; every half hour to an hour it switches for about a minute into active sleep, with fast changes in skin color and texture, eye movements and twitches, while still hard to wake. Brain recordings in Octopus laqueus show active sleep looks like waking brain activity, and its skin patterns resemble ones used while awake. Scientists are still working out what active sleep is for.
- True of
- octopuses studied in labs: Octopus insularis (Brazil) and Octopus laqueus (Japan)
- Must keep
scientists are still finding out
- Numbers
- about 1 minute length of an active-sleep boutmedian 40.8 s in Octopus insularis (Medeiros et al. 2021); roughly 1-minute bouts in Octopus laqueus (Pophale et al. 2023)
- roughly every 30 to 60 minutes time between active-sleep bouts60% of recurrences 26–39 min in Octopus insularis; roughly every 60 min in Octopus laqueus
- First fold
- Fold 4
3 sources
- iScience (via PubMed Central) Cyclic alternation of quiet and active sleep states in the octopus journal, 2021
- Nature Wake-like skin patterning and neural activity during octopus sleep journal, 2023
- Okinawa Institute of Science and Technology (OIST) Octopus sleep is surprisingly similar to humans and contains a wake-like stage university, 2023
The octopuses first learned to open the container, then had to steer it through the hole, which only works if the octopus pulls, releases and pushes at the right moments. All seven learned it, and each coped when the container was turned a new way, put behind an opaque barrier or presented at random angles, though they slowed down briefly at each change.
- True of
- common octopus (Octopus vulgaris), one lab study of 7 animals
- First fold
- Fold 5
2 sources
- PLoS ONE (via PubMed Central) Pull or Push? Octopuses Solve a Puzzle Problem journal, 2016
- Monterey Bay Aquarium Giant Pacific octopus aquarium
Researchers filming the site in Jervis Bay counted 102 throws in their 2015 videos. Some happened while the octopuses were clearing out their dens, others during encounters with other octopuses, and 17 throws hit another octopus. The team found evidence that some throws may have been aimed, but that is still being tested; it is the first report of throwing by any octopus.
- True of
- gloomy octopus (Octopus tetricus), one high-density site in Jervis Bay, Australia
- Must keep
scientists are still finding out
- Numbers
- 102 throws recorded in the 2015 videoscounts from one study (Godfrey-Smith et al. 2022), reported independently by The Guardian
- 17 of 102 (about 17%) throws that hit another octopuscounts from one study (Godfrey-Smith et al. 2022), reported independently by The Guardian
- First fold
- Fold 5
2 sources
- PLOS ONE In the line of fire: Debris throwing by wild octopuses journal, 2022
- The Guardian Octopuses throw objects at one another, researchers observe news, 2022
An octopus spends much of its time tucked in its den and returns to it to eat after hunting. Tight spaces keep a soft-bodied octopus safe from predators. On sandy seabeds, common octopuses dig dens and may line them with shells, and young ones can hide between the halves of an empty clam shell.
- True of
- most bottom-living octopuses
- First fold
- Fold 1
3 sources
- Seattle Aquarium Giant Pacific octopus aquarium
- Monterey Bay Aquarium Giant Pacific octopus aquarium
- Ecology and Evolution (via PubMed Central) Bivalve Shell Utilization by Juvenile Octopus vulgaris in Sandy Substrates journal, 2025
Carrying the shells slows the octopus down, because it has to walk on stiff arms with the shells held underneath, so it gains nothing until it stops somewhere open and needs a hiding place. That delayed payoff is why Finn, Tregenza and Norman (2009) called it tool use. Coconut carrying is known only from this species, in Indonesia.
- True of
- veined octopus (Amphioctopus marginatus) only, Indonesia
- Must keep
some
- Corrects
- Coconut carrying is not something all octopuses do; it has been recorded only in the veined octopus.
- First fold
- Fold 1
3 sources
- Current Biology (via PubMed) Defensive tool use in a coconut-carrying octopus journal, 2009
- National Geographic "Bizarre" Octopuses Carry Coconuts as Instant Shelters news, 2009
- Australian Museum Veined Octopus museum
Octopods occur at all latitudes from the equator to polar waters and from the intertidal zone into the deep sea (FAO); National Geographic describes octopuses from the tropics to the poles, on coral reefs and sand flats, and from tide pools to the abyss. The FAO says cephalopods live in all the world's oceans and names the Black Sea as the exception. The deepest sighting is in dumbo-deep.
- True of
- octopuses as a group
- First fold
- Fold 1
2 sources
- Food and Agriculture Organization of the United Nations (FAO) Cephalopods of the World, Vol. 3: Octopods and Vampire Squids (Jereb, Roper, Norman & Finn, eds.) book, 2016
- National Geographic Why Do Octopuses Remind Us So Much of Ourselves? news
A heap of crab shells and empty clam shells is a telltale sign that an octopus lives nearby. Because the pile is a record of meals, scientists sort through middens to learn what octopuses eat.
- True of
- many den-living octopuses, e.g. giant Pacific octopus and common octopus
- Must keep
often
- First fold
- Fold 3
3 sources
- Monterey Bay Aquarium Giant Pacific octopus aquarium
- Seattle Aquarium Giant Pacific octopus aquarium
- Ecology and Evolution (via PubMed Central) Bivalve Shell Utilization by Juvenile Octopus vulgaris in Sandy Substrates journal, 2025
An octopus usually keeps to its own den, and when two octopuses meet they may fight. That is why the few places where many octopuses live close together surprised scientists.
- True of
- most octopuses
- Must keep
most
- First fold
- Fold 3
3 sources
- Monterey Bay Aquarium Giant Pacific octopus aquarium
- PLOS ONE In the line of fire: Debris throwing by wild octopuses journal, 2022
- Current Biology (via PubMed) Signal Use by Octopuses in Agonistic Interactions journal, 2016
Octopods are exclusively marine: none has colonized fresh water, because, like nearly all cephalopods, they tolerate low salt poorly (FAO). Britannica likewise describes cephalopods as exclusively marine animals. Some intertidal octopuses, such as Abdopus, may cope with rock pools that turn saltier in the sun or fresher after heavy rain (FAO).
- True of
- all octopuses
- Corrects
- That some octopuses live in rivers or lakes.
- First fold
- Fold 3
2 sources
- Food and Agriculture Organization of the United Nations (FAO) Cephalopods of the World, Vol. 3: Octopods and Vampire Squids (Jereb, Roper, Norman & Finn, eds.) book, 2016
- Encyclopaedia Britannica Cephalopod encyclopedia
Young common octopuses in Bermuda were seen removing rocks from inside their dens and bringing objects to block the opening, and wild octopuses have been seen stacking rocks at their den entrances. Gloomy octopuses in Australia sometimes gather collections of objects around the rims of their den holes.
- True of
- some octopuses, e.g. young common octopuses (Bermuda) and gloomy octopus
- Must keep
some
- First fold
- Fold 4
3 sources
- Ecology and Evolution (via PubMed Central) Bivalve Shell Utilization by Juvenile Octopus vulgaris in Sandy Substrates journal, 2025
- The Guardian Alien intelligence: the extraordinary minds of octopuses and other cephalopods news, 2017
- Communicative & Integrative Biology (via PubMed Central) Octopus engineering, intentional and inadvertent journal, 2017
Each site sits on a bed of discarded scallop shells, probably built up over time from the octopuses' own meal leftovers, and the shells make good dens where hiding places are otherwise scarce. There the octopuses signal to each other, mate, fight and even evict one another from dens. The scientists stress these are clusters of separate homes, not planned cities.
- True of
- gloomy octopus (Octopus tetricus), two sites in Jervis Bay, Australia
- Numbers
- up to about 15 gloomy octopuses at the second site (Octlantis)Scheel et al. 2017: up to 15 on visits so far
- First fold
- Fold 5
2 sources
- Communicative & Integrative Biology (via PubMed Central) Octopus engineering, intentional and inadvertent journal, 2017
- Smithsonian Magazine Octopus 'City' Found Off the Coast of Australia news, 2017
Octopus vulgaris has been reported from the shoreline to 250 m but typically lives shallower than 100 m, on rocky, sandy or muddy bottoms of the continental shelf (FAO). Britannica describes it living in holes and crevices on rocky bottoms and as widespread in tropical and temperate seas, and National Geographic gives its range as the tropical and temperate waters of the world's oceans. The FAO catalog is stricter: it treats the true common octopus as a Mediterranean and north-east Atlantic species and says look-alikes elsewhere, long called O. vulgaris, may be separate species awaiting study.
- True of
- common octopus (Octopus vulgaris)
- Must keep
mostly
- Numbers
- shallower than 100 m (recorded to 250 m) usual depthFAO; single source
- Corrects
- That the common octopus is one species found worldwide; its worldwide 'range' likely spans several species.
- First fold
- Fold 5
3 sources
- Food and Agriculture Organization of the United Nations (FAO) Cephalopods of the World, Vol. 3: Octopods and Vampire Squids (Jereb, Roper, Norman & Finn, eds.) book, 2016
- Encyclopaedia Britannica Octopus encyclopedia
- National Geographic Common Octopus news
Female octopuses lay eggs, one by one or in strings, usually fixed to rock or shell; some species carry them in their arms or web instead (FAO). The giant Pacific octopus lays her eggs outside her body and hangs them from the roof of her den (Monterey Bay Aquarium), and the common octopus lays hers under rocks or in holes (Britannica). In one open-ocean octopus, Ocythoe, the eggs hatch inside the mother's long oviducts before the young leave her (FAO).
- True of
- all octopuses
- First fold
- Fold 1
3 sources
- Food and Agriculture Organization of the United Nations (FAO) Cephalopods of the World, Vol. 3: Octopods and Vampire Squids (Jereb, Roper, Norman & Finn, eds.) book, 2016
- Monterey Bay Aquarium Giant Pacific octopus aquarium
- Encyclopaedia Britannica Octopus encyclopedia
All the familiar finless octopods brood their eggs: the female tends, cleans, jets water over and protects them until they hatch (FAO). The flow brings oxygen and stops algae and bacteria growing on the eggs. A giant Pacific octopus mother fans her eggs with her arms or shoots streams of water over them for months and does not eat (Monterey Bay Aquarium). A common octopus mother cleans her eggs with her suckers (Britannica).
- True of
- female octopuses of the familiar finless kind (incirrate octopods)
- First fold
- Fold 1
3 sources
- Food and Agriculture Organization of the United Nations (FAO) Cephalopods of the World, Vol. 3: Octopods and Vampire Squids (Jereb, Roper, Norman & Finn, eds.) book, 2016
- Monterey Bay Aquarium Giant Pacific octopus aquarium
- Encyclopaedia Britannica Octopus encyclopedia
Its hatchling is just over a quarter of an inch (about 6 to 7 mm) long, weighs about 22 milligrams, and already has about 14 tiny suckers on each arm (Monterey Bay Aquarium). Alaska's Department of Fish and Game also describes the young as about the size of a grain of rice, floating as plankton before they settle. The FAO catalog gives the eggs as about 6 to 8 mm long. By age two a young giant Pacific octopus may weigh around 9 kg (20 lb) (Monterey Bay Aquarium).
- True of
- giant Pacific octopus (Enteroctopus dofleini)
- Numbers
- about a rice grain; 6–8 mm long egg sizeMonterey Bay Aquarium (egg the size of a rice grain); FAO (6–8 mm); ADFG gives rice-grain size for the hatchlings
- about 22 mg hatchling weightMonterey Bay Aquarium; single source
- about 14 suckers per arm at hatchingMonterey Bay Aquarium; single source
- First fold
- Fold 1
3 sources
- Monterey Bay Aquarium Giant Pacific octopus aquarium
- Alaska Department of Fish and Game Giant Pacific Octopus (Enteroctopus dofleini) Species Profile government, 2021
- Food and Agriculture Organization of the United Nations (FAO) Cephalopods of the World, Vol. 3: Octopods and Vampire Squids (Jereb, Roper, Norman & Finn, eds.) book, 2016
The FAO catalog estimates that most warmer-water octopods live only 1 to 2 years and gives the same range for the common octopus; National Geographic lists 1 to 2 years for the common octopus in the wild. The giant Pacific octopus lives unusually long for an octopus, about 3 to 5 years, and like most octopuses it breeds once near the end of its life (Monterey Bay Aquarium). Some cold-water and deep-sea species live longer (see lifespan-range).
- True of
- most octopus species, especially warmer-water ones; giant Pacific octopus named
- Must keep
most
- Numbers
- about 1–2 years typical octopus lifespanFAO (most warmer-water species; common octopus); National Geographic (common octopus)
- about 3–5 years giant Pacific octopus lifespanMonterey Bay Aquarium; Alaska Department of Fish and Game also gives 3–5 years
- Corrects
- That every octopus lives less than a year, or that all species live the same length of time.
- First fold
- Fold 3
3 sources
- Food and Agriculture Organization of the United Nations (FAO) Cephalopods of the World, Vol. 3: Octopods and Vampire Squids (Jereb, Roper, Norman & Finn, eds.) book, 2016
- National Geographic Common Octopus news
- Monterey Bay Aquarium Giant Pacific octopus aquarium
The Monterey Bay Aquarium gives 18,000 to 74,000 eggs, occasionally up to 100,000, hung in hundreds of strands of about 250 eggs each; Alaska's Department of Fish and Game and the FAO catalog both give up to 100,000. The common octopus lays even more, 100,000 to 500,000 (FAO). Species with large eggs lay far fewer: Diguet's pygmy octopus lays 50 to 250 (FAO).
- True of
- giant Pacific octopus (Enteroctopus dofleini); other species named
- Numbers
- up to about 100,000 eggs giant Pacific octopus clutch, maximumMonterey Bay Aquarium; ADFG; FAO
- 18,000–74,000 eggs giant Pacific octopus clutch, usual rangeMonterey Bay Aquarium; single source
- 100,000–500,000 eggs common octopus clutchFAO; single source
- 50–250 eggs Diguet's pygmy octopus clutchFAO; single source
- Corrects
- That every octopus lays many thousands of eggs; big-egged species lay tens or hundreds.
- First fold
- Fold 3
3 sources
- Monterey Bay Aquarium Giant Pacific octopus aquarium
- Alaska Department of Fish and Game Giant Pacific Octopus (Enteroctopus dofleini) Species Profile government, 2021
- Food and Agriculture Organization of the United Nations (FAO) Cephalopods of the World, Vol. 3: Octopods and Vampire Squids (Jereb, Roper, Norman & Finn, eds.) book, 2016
Octopods hatch either as drifting young (paralarvae) or as well-developed young that live like adults from the start; small eggs tend to give drifting young and large eggs crawl-away young (FAO). Giant Pacific octopus hatchlings float near the surface for weeks to several months, depending on water temperature, before settling (ADFG). The deep-sea Graneledone boreopacifica hatches as a virtual miniature adult with no drifting stage (Robison et al. 2014). No octopus parent cares for the young after they hatch (FAO).
- True of
- octopus species in general; the pattern differs by species
- Must keep
many
- First fold
- Fold 3
3 sources
- Food and Agriculture Organization of the United Nations (FAO) Cephalopods of the World, Vol. 3: Octopods and Vampire Squids (Jereb, Roper, Norman & Finn, eds.) book, 2016
- Alaska Department of Fish and Game Giant Pacific Octopus (Enteroctopus dofleini) Species Profile government, 2021
- PLOS ONE Deep-Sea Octopus (Graneledone boreopacifica) Conducts the Longest-Known Egg-Brooding Period of Any Animal (Robison, Seibel & Drazen) journal, 2014
The vast majority of finless octopods appear to lay eggs only once and die around the time the eggs hatch (FAO). While she broods, the mother does not eat, slowly weakens and dies at about the time her young hatch (Alaska Department of Fish and Game); MBARI says the same of most female octopuses. Male giant Pacific octopuses die a few weeks after mating (ADFG). This is the ordinary end of an octopus life; tell it gently, as the mother spending the last part of her life caring for her eggs.
- True of
- females of most octopus species (incirrate octopods)
- Must keep
most
- Corrects
- That the mother is killed by her babies, or that octopus mothers raise their young after hatching.
- First fold
- Fold 4
3 sources
- Food and Agriculture Organization of the United Nations (FAO) Cephalopods of the World, Vol. 3: Octopods and Vampire Squids (Jereb, Roper, Norman & Finn, eds.) book, 2016
- Alaska Department of Fish and Game Giant Pacific Octopus (Enteroctopus dofleini) Species Profile government, 2021
- Monterey Bay Aquarium Research Institute (MBARI) Deep-sea octopus broods eggs for over four years—longer than any known animal university, 2014
MBARI researchers led by Bruce Robison found the female on a rock ledge about 1,400 m deep in Monterey Canyon, California, in May 2007 and returned 18 times; by October 2011 she was gone, leaving about 160 empty egg cases (Robison, Seibel & Drazen 2014, PLOS ONE). She was never seen eating, and her skin grew pale and loose. The water there is about 3 °C, and cold slows the eggs' development; the young hatch large and well developed. The previous octopus record, 14 months, came from a laboratory study.
- True of
- one observed female Graneledone boreopacifica in Monterey Canyon
- Must keep
about
- Numbers
- about 53 months (4.5 years) brooding periodRobison et al. 2014; MBARI; National Geographic (Ed Yong); all from one observed female, one study
- about 1,400 m (1,397 m) depth of brooding siteRobison et al. 2014 (1,397 m); National Geographic (1,400 m); MBARI; all from one observed female, one study
- about 160 eggs (155–165) clutch sizeRobison et al. 2014 (155–165); National Geographic (160); MBARI; all from one observed female, one study
- about 3 °C water temperatureRobison et al. 2014 (2.8–3.4 °C); MBARI (about 3 °C)
- 14 months (lab) previous octopus brooding recordRobison et al. 2014; single source
- First fold
- Fold 5
3 sources
- PLOS ONE Deep-Sea Octopus (Graneledone boreopacifica) Conducts the Longest-Known Egg-Brooding Period of Any Animal (Robison, Seibel & Drazen) journal, 2014
- Monterey Bay Aquarium Research Institute (MBARI) Deep-sea octopus broods eggs for over four years—longer than any known animal university, 2014
- National Geographic Octopus Cares For Her Eggs For 53 Months, Then Dies (Ed Yong) news, 2014
In the laboratory, Diguet's pygmy octopus from Mexico completes its whole life cycle in 125 to 240 days (FAO), and the Two Oceans Aquarium gives the tiny Wolfi octopus a lifespan of roughly six months. Some polar species are estimated to live at least 6 years (FAO). A deep-sea Graneledone boreopacifica mother brooded for 53 months, which suggests that species may be among the longest-lived cephalopods (Robison et al. 2014). How long most deep-sea octopods live is still poorly known.
- True of
- octopus species compared; each figure is for the named species
- Must keep
some
- Numbers
- 125–240 days Diguet's pygmy octopus life cycle (lab)FAO; single source
- about 6 months Wolfi octopus lifespanTwo Oceans Aquarium; single source
- at least 6 years (estimated) some polar speciesFAO; single source
- 53 months Graneledone boreopacifica brooding aloneRobison et al. 2014; also MBARI (see brooding-record)
- First fold
- Fold 5
3 sources
- Food and Agriculture Organization of the United Nations (FAO) Cephalopods of the World, Vol. 3: Octopods and Vampire Squids (Jereb, Roper, Norman & Finn, eds.) book, 2016
- Two Oceans Aquarium Wolfi octopus aquarium
- PLOS ONE Deep-Sea Octopus (Graneledone boreopacifica) Conducts the Longest-Known Egg-Brooding Period of Any Animal (Robison, Seibel & Drazen) journal, 2014
In the familiar octopuses the male's third arm, typically on the right, has a groove along its length ending in a spoon-shaped tip (FAO). During mating he places the tip inside the female's mantle cavity and passes spermatophores, sealed packets of sperm, along the groove (FAO; Britannica). Females can store sperm and use it later to fertilize their eggs. In argonauts it is the third left arm, and the finned deep-sea octopods have no such arm (FAO).
- True of
- males of most octopuses (not the finned deep-sea octopods)
- First fold
- Fold 5
2 sources
- Food and Agriculture Organization of the United Nations (FAO) Cephalopods of the World, Vol. 3: Octopods and Vampire Squids (Jereb, Roper, Norman & Finn, eds.) book, 2016
- Encyclopaedia Britannica Octopus encyclopedia
In 1977 Jerome Wodinsky removed the optic glands from brooding Caribbean two-spot octopus mothers; they abandoned their eggs, began eating again and lived for months longer (University of Chicago). In the California two-spot octopus, Wang and Ragsdale (2018) found the gland switches several signaling pathways up and down, including steroid, insulin, catecholamine and feeding-peptide pathways, rather than releasing one 'self-destruct' hormone. A 2022 Current Biology study found big shifts in the gland's cholesterol and steroid chemistry after reproduction. Some captive mothers injure themselves near the end.
- True of
- female octopuses studied: Octopus hummelincki and Octopus bimaculoides
- Must keep
scientists are still finding out
- Corrects
- That a single 'death hormone' has been identified, or that the mother chooses to die.
- First fold
- Fold 6 (not for young readers)
2 sources
- Journal of Experimental Biology (PubMed) Multiple optic gland signaling pathways implicated in octopus maternal behaviors and death (Wang & Ragsdale) journal, 2018
- University of Chicago News What causes the octopus death spiral? New study points to changes in cholesterol production university, 2022
Alaska's Department of Fish and Game gives adult weights of 10 to 50 kg (22 to 110 lb), averaging 20 to 30 kg, and arm spans up to about 5 m (16 ft); the Monterey Bay Aquarium says a full-grown animal can weigh more than 23 kg (50 lb) and span 2 to 4 m or more. Record claims vary widely: the aquarium's heaviest on record is 91 kg (200 lb) and nearly 6 m (20 ft) across, Canadian researchers recorded a 71 kg (156 lb) animal, and the FAO catalog gives body weight 'greater than 180 kg' without detail. The FAO also names the open-ocean seven-arm octopus (Haliphron atlanticus) as the other giant, with arm spans likely over 3 to 4 m. It lives in the cold North Pacific from Japan to Alaska and Baja California.
- True of
- giant Pacific octopus (Enteroctopus dofleini)
- Numbers
- about 20–30 kg (45–65 lb) average; range 10–50 kg typical adult weightADFG; Monterey Bay Aquarium: full-grown can exceed 23 kg (50 lb)
- about 2–4 m (7–13 ft), up to about 5 m (16 ft) typical arm spanMonterey Bay Aquarium 2–4 m or more; ADFG up to 16 ft
- 71–91 kg (156–200 lb) heaviest well-reported animalsADFG 156 lb (Canadian researchers); Monterey Bay Aquarium 200 lb, nearly 20 ft across
- over 180 kg largest weight claim in referencesFAO catalog, no specimen detail; a record claim, never typical
- Corrects
- Stating record or legendary sizes (180+ kg, 9 m spans) as the normal size of the species.
- First fold
- Fold 1
3 sources
- Monterey Bay Aquarium Giant Pacific octopus aquarium
- Alaska Department of Fish and Game Giant Pacific Octopus (Enteroctopus dofleini) Species Profile government, 2021
- Food and Agriculture Organization of the United Nations (FAO) Cephalopods of the World, Vol. 3: Octopods and Vampire Squids (Jereb, Roper, Norman & Finn, eds.) book, 2016
References disagree on which species is the very smallest. The Two Oceans Aquarium calls the star-sucker pygmy octopus (Octopus wolfi) of the western Pacific the world's smallest, weighing under a gram; the FAO catalog lists it at up to 15 mm mantle length and 45 mm total length, and says pygmy octopuses mature at under one gram. Guinness World Records instead names Octopus arborescens of Sri Lanka, with an average arm span under 5.1 cm (2 in). When naming a species, say 'one of the smallest'.
- True of
- the smallest octopus species, such as Octopus wolfi and Octopus arborescens
- Numbers
- under 1 g adult weight of pygmy octopusesFAO (pygmy octopuses in general); Two Oceans Aquarium (O. wolfi)
- mantle to 15 mm; total length to 45 mm Octopus wolfi sizeFAO catalog; single source
- under 5.1 cm (2 in) on average Octopus arborescens arm spanGuinness World Records; single source here
- Corrects
- Naming one species as the undisputed smallest octopus; Guinness and the Two Oceans Aquarium name different species.
- First fold
- Fold 1
3 sources
- Two Oceans Aquarium Wolfi octopus aquarium
- Food and Agriculture Organization of the United Nations (FAO) Cephalopods of the World, Vol. 3: Octopods and Vampire Squids (Jereb, Roper, Norman & Finn, eds.) book, 2016
- Guinness World Records Smallest species of octopus encyclopedia
National Geographic puts the count at around 300 octopus species. The FAO's world catalog of octopods (2016) covers 280 named species, counting the single vampire squid, and says the family of familiar bottom-living octopuses alone likely holds more than 300 species, over 150 of them still awaiting a formal scientific description. Most of the undescribed ones live in the tropical Indo-West Pacific, where octopus diversity is highest. Any exact count is a snapshot.
- True of
- octopuses as a group (order Octopoda)
- Must keep
about
- Numbers
- about 300 known octopus speciesNational Geographic; FAO: the family Octopodidae alone likely exceeds 300, many undescribed
- 280 named species in the FAO octopod catalogFAO 2016; includes the vampire squid
- more than 150 octopus species awaiting formal descriptionFAO 2016; single source
- Corrects
- Giving an exact, final species count; new species are still being described.
- First fold
- Fold 3
2 sources
- National Geographic Why Do Octopuses Remind Us So Much of Ourselves? news
- Food and Agriculture Organization of the United Nations (FAO) Cephalopods of the World, Vol. 3: Octopods and Vampire Squids (Jereb, Roper, Norman & Finn, eds.) book, 2016
Dumbo octopuses (genus Grimpoteuthis) are named for their large ear-like fins, which with their webbed arms help them swim (NOAA Ocean Today). In a study published in Marine Biology in 2020, Alan Jamieson and Michael Vecchione reported video-lander sightings of Grimpoteuthis at 5,760 m and 6,957 m in the Indian Ocean, extending the known depth range of cephalopods by 1,812 m and giving the first unequivocal sighting of a cephalopod in the hadal zone, deeper than 6,000 m. Guinness World Records lists the 6,957 m animal, in the Java Trench, as the deepest cephalopod.
- True of
- dumbo octopuses (genus Grimpoteuthis)
- Numbers
- 6,957 m (22,825 ft) deepest octopus sightingJamieson & Vecchione 2020; Guinness World Records
- 1,812 m extension of known cephalopod depth rangeJamieson & Vecchione 2020; Guinness World Records
- 5,145 m previous deepest camera recordJamieson & Vecchione 2020; single source
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- Fold 3
3 sources
- NOAA Ocean Today Dance of the Dumbo Octopus government
- Marine Biology (NOAA Institutional Repository) First in situ observation of Cephalopoda at hadal depths (Octopoda: Opisthoteuthidae: Grimpoteuthis sp.), Jamieson & Vecchione journal, 2020
- Guinness World Records Deepest cephalopod encyclopedia, 2020
National Geographic's species card gives 12 to 36 inches and 6.6 to 22 pounds, and says averages are much smaller than the largest animals. The biggest reported sizes differ between sources: National Geographic gives about 1.3 m (4.3 ft) long and up to 10 kg (22 lb); the FAO catalog gives total length to around 1.8 m and body weight over 20 kg, with a mantle (body) length to 40 cm, but says most are smaller, about 25 cm mantle length. Britannica calls it a medium-sized octopus. Use the typical range and label any maximum as a maximum.
- True of
- common octopus (Octopus vulgaris)
- Must keep
usually
- Numbers
- about 30–90 cm (12–36 in) typical total length (arms included)National Geographic species card; single source
- up to about 10 kg (22 lb); averages much smaller adult weightNational Geographic species card (lists 6.6–22 lb and says averages are much smaller); single source
- about 1.3 m (NatGeo) to about 1.8 m (FAO) maximum total lengthsources disagree; a maximum, not typical
- 10 kg (NatGeo) to over 20 kg (FAO) maximum weightsources disagree; a maximum, not typical
- commonly about 25 cm; up to 40 cm mantle (body) lengthFAO; Mediterranean and north-east Atlantic animals; single source
- Corrects
- Drawing or stating the maximum size as the size of an ordinary common octopus.
- First fold
- Fold 4
3 sources
- National Geographic Common Octopus news
- Food and Agriculture Organization of the United Nations (FAO) Cephalopods of the World, Vol. 3: Octopods and Vampire Squids (Jereb, Roper, Norman & Finn, eds.) book, 2016
- Encyclopaedia Britannica Octopus encyclopedia
The finless (incirrate) octopods are muscular, mostly bottom-living, usually carry an ink sac, and include most species, among them all the fished ones. The finned (cirrate) octopods are soft and semi-gelatinous, with a pair of fins, a single row of suckers flanked by finger-like cirri, and no ink sac; they live only in the deep sea and are rarely found shallower than 600 m except at high latitudes (FAO). NOAA describes the dumbo octopus using its ear-like fins and webbed arms to swim, with small sense organs, cirri, on its arms.
- True of
- octopods (order Octopoda)
- First fold
- Fold 5
2 sources
- Food and Agriculture Organization of the United Nations (FAO) Cephalopods of the World, Vol. 3: Octopods and Vampire Squids (Jereb, Roper, Norman & Finn, eds.) book, 2016
- NOAA Ocean Today Dance of the Dumbo Octopus government
The 'paper nautilus' shell is not a true mollusk shell but a brood case, secreted by webs on the tips of the female's first pair of arms, which protects strings of eggs laid inside; a female can repair or rebuild it (FAO). Britannica likewise says argonaut eggs are carried in a special shell secreted by the female. Male argonauts are tiny and never make a shell (FAO). Argonauts live near the surface of the open ocean.
- True of
- argonauts (genus Argonauta), females
- First fold
- Fold 5
2 sources
- Food and Agriculture Organization of the United Nations (FAO) Cephalopods of the World, Vol. 3: Octopods and Vampire Squids (Jereb, Roper, Norman & Finn, eds.) book, 2016
- Encyclopaedia Britannica Cephalopod encyclopedia
The mollusk phylum includes snails, clams and chitons; within it the class Cephalopoda includes squid, cuttlefish, nautilus and octopuses (Alaska Department of Fish and Game). The Monterey Bay Aquarium calls the giant Pacific octopus a mollusk, a boneless invertebrate related to clams, with squid, cuttlefish, nautilus and argonauts as relatives. Britannica notes that cephalopod ancestors seem closest to the ancestors of snails (gastropods).
- True of
- all octopuses
- First fold
- Fold 3
3 sources
- Alaska Department of Fish and Game Giant Pacific Octopus (Enteroctopus dofleini) Species Profile government, 2021
- Monterey Bay Aquarium Giant Pacific octopus aquarium
- Encyclopaedia Britannica Cephalopod encyclopedia
Cephalopods began more than 500 million years ago as small animals with shells (National Geographic). Except for the nautilus, every living cephalopod has a greatly reduced shell, overgrown by the body (Britannica). Cuttlefish keep a thick internal cuttlebone that they use to control buoyancy, squid only a horny 'pen', and in octopods the shell survives as small cartilage-like rods (stylets) or as fin supports in the finned deep-sea kinds (Britannica). In the giant Pacific octopus it is two small plates where head muscles anchor (Monterey Bay Aquarium).
- True of
- living cephalopods; octopuses (Octopoda)
- First fold
- Fold 4
3 sources
- Encyclopaedia Britannica Cephalopod encyclopedia
- Monterey Bay Aquarium Giant Pacific octopus aquarium
- National Geographic Why Do Octopuses Remind Us So Much of Ourselves? news
The first cephalopods, the nautiloids, appeared in the Late Cambrian, over 500 million years ago (FAO). National Geographic describes them evolving from a small animal with a shell like a witch's hat, and notes that 450 million years ago some of the fiercest ocean predators were shelled cephalopods. Octopuses have soft bodies and seldom fossilize; a fossil from Lebanon about 90 million years old is one of the oldest octopuses known (National Geographic).
- True of
- cephalopods (the class that includes octopuses)
- Must keep
more than
- Numbers
- more than 500 million years ago first cephalopods appearedFAO; National Geographic
- about 90 million years age of one of the oldest octopus fossilsNational Geographic; single source
- First fold
- Fold 5
2 sources
- Food and Agriculture Organization of the United Nations (FAO) Cephalopods of the World, Vol. 3: Octopods and Vampire Squids (Jereb, Roper, Norman & Finn, eds.) book, 2016
- National Geographic Why Do Octopuses Remind Us So Much of Ourselves? news
The WHO growth reference gives median heights at exactly 8 years of 127.3 cm for boys and 126.6 cm for girls; the US CDC growth charts give 128.1 cm for boys and 127.8 cm for girls at 96.5 months. Children the same age vary a lot: between the 3rd and 97th percentiles, eight-year-olds span roughly 1.16 to 1.39 m. The books use this as a scale figure beside animals, not as a fact about octopuses.
- True of
- children aged about 8 (WHO and CDC reference medians)
- Must keep
about
- Numbers
- about 1.27 m (4 ft 2 in) median height at 8 yearsWHO 8:0 boys 127.3 cm, girls 126.6 cm; CDC 96.5 months boys 128.1 cm, girls 127.8 cm
- about 1.16–1.39 m 3rd to 97th percentile at 8 yearsWHO boys 116.6–137.9, girls 115.7–137.5; CDC boys 117.5–139.3 cm
- First fold
- Fold 1
3 sources
- US Centers for Disease Control and Prevention CDC growth charts data files: stature-for-age percentiles, ages 2 to 20 (statage.csv) government, 2000
- World Health Organization Height-for-age, boys 5 to 19 years: simplified field tables, percentiles (WHO 2007 growth reference) government, 2007
- World Health Organization Height-for-age, girls 5 to 19 years: simplified field tables, percentiles (WHO 2007 growth reference) government, 2007
Merriam-Webster and Cambridge give the plural as 'octopuses or octopi', and Merriam-Webster also records 'octopodes'. Merriam-Webster's usage guide explains that 'octopi' came from treating the word as Latin, 'octopuses' gives it a normal English ending, and 'octopodes' follows its Greek origin. The FAO's scientific catalog standardizes on 'octopuses', which these books use.
- True of
- the English word octopus
- Corrects
- That 'octopi' is simply wrong, or that 'octopodes' is the only correct plural.
- First fold
- Fold 4
3 sources
- Merriam-Webster Octopus: definition and usage guide encyclopedia
- Cambridge Dictionary OCTOPUS | English meaning encyclopedia
- Food and Agriculture Organization of the United Nations (FAO) Cephalopods of the World, Vol. 3: Octopods and Vampire Squids (Jereb, Roper, Norman & Finn, eds.) book, 2016
The lid of Inky's tank had been left slightly ajar. Staff think he climbed out, crossed the floor during the night and squeezed into a drainpipe that runs to Hawke's Bay; they worked out the route from the wet trail he left (The Guardian; National Geographic). Nobody saw it happen, and the aquarium also floated a second route through a pipe at the top of the tank, so the path is the staff's reconstruction. A fisherman had brought Inky in after finding him in a crayfish pot.
- True of
- Inky, one octopus at the National Aquarium of New Zealand in Napier
- Must keep
believe
- Corrects
- Telling the escape route as witnessed fact; it is the staff's best reconstruction.
- First fold
- Fold 4
2 sources
- The Guardian The great escape: Inky the octopus legs it to freedom from aquarium news, 2016
- National Geographic Inky's Daring Escape Shows How Smart Octopuses Are news, 2016
Members of the genus carry powerful nerve toxins including tetrodotoxin, bites have killed people, and live animals should never be handled (FAO). The Australian Museum records several deaths in Australia: the bite may not be felt, but within minutes the lips and tongue go numb, breathing becomes hard and the breathing muscles can be paralysed, so helpers call for aid and keep the person breathing. The octopuses use the venom on crabs and small fish, hide under ledges, and show their bright blue rings only when disturbed.
- True of
- blue-ringed octopuses (genus Hapalochlaena)
- Must keep
can
- Corrects
- That blue-ringed octopuses attack people, or that octopuses in general are dangerous to people.
- First fold
- Fold 5 (not for young readers)
2 sources
- Food and Agriculture Organization of the United Nations (FAO) Cephalopods of the World, Vol. 3: Octopods and Vampire Squids (Jereb, Roper, Norman & Finn, eds.) book, 2016
- Australian Museum Blue-lined Octopus (Hapalochlaena fasciata) museum, 2021
The Act defines 'animal' as any vertebrate other than humans, any cephalopod mollusk and any decapod crustacean (section 5, in force from 22 May 2023). It sets up an Animal Sentience Committee to report on how government policy weighs animal welfare; it does not itself change fishing or restaurant practice (GOV.UK). Cephalopods and decapods were added in November 2021 after a government-commissioned review led by Jonathan Birch at the London School of Economics concluded there is strong scientific evidence that they are sentient.
- True of
- United Kingdom law
- Corrects
- That the Act bans eating or fishing octopuses; it governs how government policy considers their welfare.
- First fold
- Fold 5
3 sources
- legislation.gov.uk (The National Archives) Animal Welfare (Sentience) Act 2022, section 5: Interpretation government, 2022
- GOV.UK, Department for Environment, Food & Rural Affairs Lobsters, octopus and crabs recognised as sentient beings government, 2021
- London School of Economics and Political Science Octopuses, crabs and lobsters to be recognised as sentient beings under UK law following LSE report findings university, 2021
The Directive, adopted on 22 September 2010 and applied by member states from 1 January 2013, covers live non-human vertebrates and live cephalopods, because there is scientific evidence that cephalopods can experience pain, suffering, distress and lasting harm (Recital 8, Article 1). Bringing this class of about 700 species under the Directive led researchers to write the first guidelines for cephalopod care and welfare in research (Fiorito et al. 2015). A 2024 amendment adds care and humane-killing rules for cephalopods, applying from 4 December 2026 (Norecopa).
- True of
- European Union law on animals used in science
- First fold
- Fold 5
3 sources
- EUR-Lex, Publications Office of the European Union Directive 2010/63/EU on the protection of animals used for scientific purposes government, 2010
- Laboratory Animals (PubMed) Guidelines for the Care and Welfare of Cephalopods in Research: a consensus based on an initiative by CephRes, FELASA and the Boyd Group (Fiorito et al.) journal, 2015
- Norecopa EU Directive 2010/63/EU on the protection of animals used for scientific purposes ngo
Washington's House Bill 1153 prohibits octopus aquaculture in the state; the governor signed it on 13 March 2024 and it took effect on 6 June 2024. California's AB 3162, approved on 27 September 2024, makes it unlawful to farm any species of octopus for human consumption and bars businesses from selling, possessing or transporting farmed octopus. Both laws drew on octopus intelligence and capacity for pain: Washington's through testimony at its hearings (House Bill Report), California's in the law's written findings, which also cite the 2021 LSE review.
- True of
- Washington and California (United States), laws passed in 2024
- Corrects
- That octopus farming is banned across the United States; these are state laws.
- First fold
- Fold 5
3 sources
- Washington State Legislature HB 1153 (2023-24): Prohibiting octopus farming, bill history government, 2024
- Washington State Legislature House Bill Report HB 1153, as passed Legislature government, 2024
- California Legislative Information AB-3162 Octopus: aquaculture: prohibition (Chapter 758, Statutes of 2024) government, 2024
Reported global octopus production rose from 179,042 metric tons in 1980 to 355,239 metric tons in 2014, and more than twenty described species are harvested in some 90 countries (Sauer et al. 2021). The FAO catalog put 2010 world production above 350,710 metric tons and estimates that more than 100 species are taken, although catch statistics name only four; much catch goes unreported. Octopuses are caught by hand, spear, lines, traps and pots, and trawls; the largest single-species fishery is for the common octopus off north-west Africa (FAO).
- True of
- world octopus fisheries (all species combined)
- Must keep
about
- Numbers
- about 350,000 t a year (2010s) reported world octopus catchSauer et al. 2021: 355,239 t in 2014; FAO: over 350,710 t in 2010
- 179,042 t reported catch in 1980Sauer et al. 2021; single source
- First fold
- Fold 5
2 sources
- Reviews in Fisheries Science & Aquaculture World Octopus Fisheries (Sauer et al.) journal, 2021
- Food and Agriculture Organization of the United Nations (FAO) Cephalopods of the World, Vol. 3: Octopods and Vampire Squids (Jereb, Roper, Norman & Finn, eds.) book, 2016
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