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Giant Pacific Octopus

Enteroctopus dofleini (Wülker 1910)

Behavior

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Each pair of arms of giant Pacific octopuses has up to 280 suckers, which have thousands of chemical receptors. These provide an acute sense of touch and taste, which this species use to help detect prey. Typically calm animals, giant Pacific octopuses are unusually adept at navigating by using landmarks in the wild and at adapting objects as tools. They are the only invertebrate known to use their well-developed vision to learn through observation. Giant Pacific octopuses are considered extremely intelligent, partially do to their larger-than-average brain-to-body weight ratio. Individuals in captivity are known for having having unique temperaments and personalities, ranging from playful to destructive. Their high level of intelligence and desire to interact with human caretakers have earned captive members of this spices a reputation as notorious escape artists.

Perception Channels: visual ; tactile ; chemical

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Hartis, C. 2011. "Enteroctopus dofleini" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Enteroctopus_dofleini.html
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Colleen Hartis, Radford University
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Karen Francl, Radford University
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Gail McCormick, Special Projects
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Conservation Status

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Giant Pacific octopuses are not considered at risk by the IUCN Red List, CITES, or the US Federal List of Endangered Species. Although this spices is commercially fished in some areas, this does not appear to be greatly affecting population sizes.

US Federal List: no special status

CITES: no special status

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Hartis, C. 2011. "Enteroctopus dofleini" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Enteroctopus_dofleini.html
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Colleen Hartis, Radford University
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Karen Francl, Radford University
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Gail McCormick, Special Projects
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Life Cycle

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The lifespan of giant Pacific octopuses is characterized by a fast growth period that continues throughout its entire life of 4 to 5 years. Larvae hatch from a cluster of eggs and are on average 9.5 to 10.1 mm in length. The larvae, with limited swimming ability, move to the surface to begin a planktonic existence that lasts 1 to 3 months. At the end of the planktonic stage, juveniles descend to the benthos where they undergo rapid growth. Giant Pacific octopuses continue to grow until they reproduce. Within 3 months of breeding, males normally undergo a period of senescence and die. Symptoms of senescence in this species include reduced food intake, retraction of skin around the eyes, aimless movement (wandering) and lesions that do not heal. Females that survive brooding undergo a similar period of senescence and die within weeks of the eggs hatching.

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Hartis, C. 2011. "Enteroctopus dofleini" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Enteroctopus_dofleini.html
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Colleen Hartis, Radford University
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Karen Francl, Radford University
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Gail McCormick, Special Projects
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Benefits

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There are no known adverse effects of giant Pacific octopuses on humans.

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Hartis, C. 2011. "Enteroctopus dofleini" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Enteroctopus_dofleini.html
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Colleen Hartis, Radford University
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Karen Francl, Radford University
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Gail McCormick, Special Projects
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Benefits

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Giant Pacific octopuses were commonly used as bait for Pacific halibut during the late 1950s and 1960s, though this is no longer a common practice. In some ares, this species is commercially fished and is eaten in some countries in the Pacific.

Positive Impacts: food

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Hartis, C. 2011. "Enteroctopus dofleini" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Enteroctopus_dofleini.html
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Colleen Hartis, Radford University
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Karen Francl, Radford University
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Gail McCormick, Special Projects
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Associations

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Giant Pacific octopuses do not specialize on any one particular species of prey and are not the main source of food for any particular predator. They do, however, serve as host to some dicyemid mesozoans. Dicyemennea nouveli is a large, conical-shaped species that reaches up to 12,000 um in length. Dicyemennea nouveli inserts the pointed anterior end of its body into the folds of the renal appendages of giant Pacific octopuses. Other members of g. Dicyemennea are also found in shallow-water cephalopods.

Commensal/Parasitic Species:

  • Dicyemennea nouveli
  • g. Dicyemennea
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Hartis, C. 2011. "Enteroctopus dofleini" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Enteroctopus_dofleini.html
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Colleen Hartis, Radford University
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Karen Francl, Radford University
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Gail McCormick, Special Projects
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Trophic Strategy

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Giant Pacific octopuses are considered generalist foragers. They return to their den in order to consume their prey, and they deposit the prey's remains at the entrance of their den. This collection of skeletal remains is known as a middens. Examination of middens indicates that the diet of giant Pacific octopuses is primarily composed of clams, crabs, fish, and squid. Giant Pacific octopuses are visual hunters that utilize a variety of hunting strategies including stalking, chasing, and camouflaging themselves in order to ambush prey. They possesses a well-developed sense of vision, allowing them to coordinate the use of all eight arms to attack their victim. Members of this species also use different methods to prepare meals for consumption. One method includes pulling the protective shell apart in order to reach the meat contained inside. Another method involves crushing prey with their strong beak located in the center of its appendages. The most common method of obtaining food, however, involves drilling a hole in the prey's shell, in which an octopus injects its toxic saliva.

Animal Foods: fish; mollusks; aquatic crustaceans

Primary Diet: carnivore (Molluscivore )

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Hartis, C. 2011. "Enteroctopus dofleini" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Enteroctopus_dofleini.html
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Colleen Hartis, Radford University
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Karen Francl, Radford University
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Gail McCormick, Special Projects
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Distribution

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Giant Pacific octopuses, Enteroctopus dofleini, are found throughout the Pacific Ocean. They have been documented as far north as the Alaskan Aleutian Islands and as far south as the Baja California region of Mexico. This species ranges as far northeast as Japan.

Biogeographic Regions: pacific ocean (Native )

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Hartis, C. 2011. "Enteroctopus dofleini" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Enteroctopus_dofleini.html
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Colleen Hartis, Radford University
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Karen Francl, Radford University
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Gail McCormick, Special Projects
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Habitat

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Giant Pacific octopuses are generally found in tidal pools and up to depths of 110 m, although they can also reside in deeper waters of up to 1,500 m. They often live in dens or lairs, under boulders, and in rock crevices. Ideal habitat for this species includes a soft substrate of mud, sand or gravel that includes large boulders for creating dens. Giant Pacific octopuses are found in greater densities near dense kelp fields. Members of this species are ectothermic, and their metabolism is dependent upon water temperature. Optimal water temperatures for giant Pacific octopuses range between 7 and 9.5 degrees Celsius.

Range depth: 0 to 1500 m.

Habitat Regions: saltwater or marine

Aquatic Biomes: benthic ; coastal

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Hartis, C. 2011. "Enteroctopus dofleini" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Enteroctopus_dofleini.html
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Colleen Hartis, Radford University
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Karen Francl, Radford University
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Gail McCormick, Special Projects
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Life Expectancy

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Giant Pacific octopuses on average live 4.5 to 5 years in the wild. A similar lifespan has been observed for members this species held in public aquariums.

Average lifespan
Status: wild:
4.5 to 5 years.

Average lifespan
Status: captivity:
4.5 to 5 years.

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Hartis, C. 2011. "Enteroctopus dofleini" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Enteroctopus_dofleini.html
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Colleen Hartis, Radford University
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Karen Francl, Radford University
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Gail McCormick, Special Projects
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Morphology

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Giant Pacific octopuses are larger than any other species of octopus. Specimens have weighed as much as 272 kg and measured 9.6 m in radius. However, most reach an average weight of 60 kg with a dorsal mantle length of 50 to 60 cm. Giant Pacific octopuses are usually reddish in color but are able to change color and texture when threatened or for camouflage. The dorsal mantle is shaped like a sack and contains the brain, reproductive organs, digestive organs, and eyes. Giant Pacific octopuses have two eyes, one on each side of their head, which provide extremely acute vision. Giant Pacific octopuses also have four pairs of arms that extend from the mantle. Each pair is covered with up to 280 suckers, which contain thousands of chemical receptors.

Average mass: 60 kg.

Other Physical Features: ectothermic ; bilateral symmetry

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Hartis, C. 2011. "Enteroctopus dofleini" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Enteroctopus_dofleini.html
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Colleen Hartis, Radford University
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Karen Francl, Radford University
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Gail McCormick, Special Projects
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Associations

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Giant Pacific octopuses avoid predation by remaining in a protective den, camouflaging itself, or hiding among kelp. Although juveniles are eaten by a variety marine life, adult giant Pacific octopuses have few predators other than humans, which have hunted this species to use as food and as bait for Pacific halibut. Giant Pacific octopuses are known for their ability to release an ink cloud, although they rarely do so as a direct form of defense. Instead, they tend to fight off predators with their arms. Once released, they use their propulsion abilities to jet away. As giant Pacific octopuses escape, they then expel a cloud of ink as a screen, allowing them to seek safe refuge.

Known Predators:

  • humans Homo sapiens

Anti-predator Adaptations: cryptic

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Hartis, C. 2011. "Enteroctopus dofleini" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Enteroctopus_dofleini.html
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Colleen Hartis, Radford University
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Karen Francl, Radford University
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Gail McCormick, Special Projects
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Reproduction

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Male reproductive organs of great Pacific octopuses are enclosed inside the mantle cavity within a genital bag. Spermatozoa are encapsulated in a spindle-shaped spermatophoric sac. Males utilizes a hectocotylized arm, a specialized tentacle used for the transfer of sperm, to insert the two spermatophores (each 1 m in length) into an oviduct located in the mantle of the female. The balloon part of the spermatophore remains inside the oviduct while the remainder of the sac hangs from the female. Eventually, the sac bursts and releases millions of spermatozoa. The entire mating process takes 2 to 3 hours. Giant Pacific octopuses are polygynous.

Mating System: polygynous

Giant Pacific octopuses breed throughout the year, though spawning peaks in winter. Males may breed with several females, but females mate only once in their lifetime. Over several days, females lay 20,000 to 100,000 rice-shaped eggs (avg. 50,000) in grape-like clusters of 200 to 300 eggs each. These clusters are hung from the ceiling of the den. Females remain with the eggs throughout the entire brooding period, guarding them from predators and using her syphon to aerate and clean the clusters. Hatching can take anywhere from 150 days to almost 1 year depending on water temperature. Cooler temperatures delay the development of the embryo and therefore lengthen incubation time.

Breeding interval: Male giant Pacific octopuses may breed with several females once reaching maturity, but females mate only once in their lifetime.

Breeding season: Giant Pacific octopuses breed year-round.

Range number of offspring: 20,000 to 100,000.

Average number of offspring: 50,000.

Average time to independence: 0 minutes.

Range age at sexual or reproductive maturity (female): 3 to 5 years.

Range age at sexual or reproductive maturity (male): 3 to 5 years.

Key Reproductive Features: semelparous ; year-round breeding ; sexual ; fertilization (Internal ); broadcast (group) spawning; oviparous

Female giant Pacific octopuses remain with their eggs throughout the entire brooding period, guarding them from predators and using their syphon to aerate and clean the clusters. Females do not leave the den during this period, not even to eat. Females die during the brooding period or shortly thereafter, and males die within three months of breeding. Therefore, there is no post-hatching parental investment evident in giant Pacific octopuses.

Parental Investment: pre-hatching/birth (Provisioning: Female, Protecting: Female)

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Hartis, C. 2011. "Enteroctopus dofleini" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Enteroctopus_dofleini.html
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Colleen Hartis, Radford University
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Karen Francl, Radford University
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Gail McCormick, Special Projects
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Look Alikes

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How to Distinguish from Similar Species: Octopus rubescens is smaller, with mantle length less than 10 cm and weight less than 200 g; its skin has small, pointed papillae but not the large skin folds found on O. dofleini.
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Habitat

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Primarily rocky subtidal; occasionally low intertidal or on sand
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Comprehensive Description

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The skin of this octopus is not smooth; instead it has extensive skin folds and large, truncate papillae. Color often some shade of dark red or reddish brown but can change color rapidly. May have white spots on the dorsal mantle and on the arm web in front of the eyes, but no "eyespots" as are seen on O. bimaculatus farther south. May grow very large, with a mantle length over 20 cm, body weight to 272 kg, and arm spread to 9 m. This is the world's largest known octopus.
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Comprehensive Description

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Biology/Natural History: The 3rd right arm of the male of this species has a large hectocotylus, about 1/5 the length of the arm. The hectocotylus is used in transferring the male's spermatophore, or package of sperm, which may be up to a meter long, to the female. The hectocotylus may be left within the mantle of the female during the process. Eggs, which look like small whitish grapes, are laid throughout the year but mainly in the winter. When the female has eggs she attaches them to the roof of a cave and guards them until they hatch. She may lay 35,000 to 70,000 eggs in a single clutch. Hatching is mainly in early spring, and the young are pelagic for one to several months before settling. The young are sometime seen swimming near the surface. Lifespan is thought to be 4-5 years. Prey include crustaceans, mollusks, and fish. The octopus are often captured in crab traps, where they are trying to steal the crabs. Females can be cannibalistic. The Seattle Aquarium recently observed an octopus catching the spiny dogfish Squalus acanthias, and in 2005 we found the picked-clean skeleton of a dogfish on the shellheap outside an octopus den. The species accumulates a large pile of shells and crab carapaces outside the den, which is usually under a boulder or in a rocky crevice. They quickly kill crabs by rasping a tiny hole through the carapace, probably with their radula, then presumably injecting poison, perhaps with their beak. Several species may be attracted to their shell pile, including Pycnopodia helianthoides and the snail Amphissa columbiana. Predators include seals, sea otters, dogfish sharks, lingcod, and man. Parasites include the mesozoans Dicyemenna abreida and Conocyema deca, which live in the kidney. This octopus is said to be capable of inflicting a painful bite but I have never seen anyone bitten, even when wrestling them off the rocks. They seem much less ready to bite than is O. rubescens.
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Distribution

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Geographical Range: Bering Sea to California; Northern Asia, Japan
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Habitat

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Depth Range: Intertidal to 100 m
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Giant Pacific octopus

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The giant Pacific octopus (Enteroctopus dofleini, formerly also Octopus apollyon), also known as the North Pacific giant octopus, is a large marine cephalopod belonging to the genus Enteroctopus. Its spatial distribution includes the coastal North Pacific, along California, Oregon, Washington, British Columbia, Alaska, Russia, Japan, and Korean Peninsula.[2] It can be found from the intertidal zone down to 2,000 m (6,600 ft), and is best adapted to cold, oxygen-rich water. It is the largest octopus species, based on a scientific record of a 71-kg (156-lb) individual weighed live.[3]

Description

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Close-up of E. dofleini showing the longitudinal folds on the body and the paddle-like papillae
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Close-up of suckers

Size

E. dofleini is distinguished from other species by its large size. Adults usually weigh around 15 kg (33 lb), with an arm span up to 4.3 m (14 ft).[4] The larger individuals have been measured at 50 kg (110 lb) and have a radial span of 6 m (20 ft)[2] American zoologist G.H. Parker found that the largest suckers on a giant Pacific octopus are about 6.4 cm (2.5 in) and can support 16 kg (35 lb) each.[2] The alternative contender for the largest species of octopus is the seven-arm octopus (Haliphron atlanticus) based on a 61-kg (134-lb) incomplete carcass estimated to have a live mass of 75 kg (165 lb).[5][6] However, a number of questionable size records would suggest E. dofleini is the largest of all octopus species by a considerable margin,[7] including a report of one up to 272 kg (600 lb) in weight with a 9-m (30-ft) arm span.[8] Guinness World Records lists the biggest as 136 kg (300 lb) with an arm span of 9.8 m (32 ft).[2][9] A UN catalog of octopuses sizes E. dofleini at 180 kg (396 lb) with an arm length of 3 m (9.8 ft).[10]

Ecology

Diet

E. dofleini preys upon shrimp, crabs, scallop, abalone, cockles, snails, clams, lobsters, fish, squid,[11] and other octopuses.[12][13] Food is procured with its suckers and then bitten using its tough beak of chitin. It has also been observed to catch spiny dogfish (Squalus acanthias) up to 1.2 m (4 ft) in length while in captivity.[14] Additionally, consumed carcasses of this same shark species have been found in giant Pacific octopus middens in the wild, providing strong evidence of these octopuses preying on small sharks in their natural habitat.[15] In May 2012, amateur photographer Ginger Morneau was widely reported to have photographed a wild giant Pacific octopus attacking and drowning a seagull, demonstrating that this species is not above eating any available source of food within its size range, even birds.[16]

Predators

Scavengers and other organisms often attempt to eat octopus eggs, even when the female is present to protect them. Giant Pacific octopus paralarvae are preyed upon by many other zooplankton and filter feeders. Marine mammals, such as harbor seals, sea otters, and sperm whales depend upon the giant Pacific octopus as a source of food. Pacific sleeper sharks are also confirmed predators of this species.[17] In addition, the octopus (along with cuttlefish and squid) is a significant source of protein for human consumption. About 3.3 million tons are commercially fished, worth $6 billion annually.[2] Over thousands of years, humans have caught them using lures, spears, pot traps, nets, and bare hands.[18] The octopus is parasitized by the mesozoan Dicyemodeca anthinocephalum, which lives in its renal appendages.[19]

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Takoyaki stall in Nishi-Magome, Tokyo

Lifespan and reproduction

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Enteroctopus dofleini spawning

The giant Pacific octopus is considered to be long-lived compared to other species, with lifespans typically 3–5 years in the wild. Many other octopuses go through a complete life cycle in one year, from egg to end of life.[2] To make up for its relatively short lifespan, the octopus is extremely prolific. It can lay between 120,000 and 400,000 eggs which are coated in chorion, and attached to a hard surface by the female. The spawn is intensively cared for exclusively by the female, who continuously blows water over it and grooms it to remove algae and other growths. While she fulfills her duty of parental care the female stays close to her spawn, never leaving to feed, leading to her death soon after the young have hatched.[20] The female's death is the result of starvation, as she subsists on her own body fats[21] during this period of approximately 6 months.[18] Hatchlings are about the size of a grain of rice,[22] and very few survive to adulthood. Their growth rate is quite rapid: starting from 0.03 g and growing to 20–40 kg (44–88 lb) at adulthood, which is an increase of around 0.9% per day.[2] Because they are cool-blooded, they are able to use most of their consumed energy for body mass, respiration, physical activity, and reproduction.[18]

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Hectocotylus arm of an octopod

During reproduction, the male octopus deposits a spermatophore (or sperm packet) more than 1 m long using his hectocotylus (specialized arm) in the female's mantle. Large spermatophores are characteristic of octopuses in this genus.[7] The female stores the spermatophore in her spermatheca until she is ready to fertilize her eggs. One female at the Seattle Aquarium was observed to retain a spermatophore for seven months before laying fertilized eggs.[18]

Unlike males, only the female giant Pacific octopuses are semelparous, meaning they only breed a single time in their life.[21] After reproduction, they enter a stage called senescence, which involves obvious changes in behavior and appearance, including a reduced appetite, retraction of skin around the eyes giving them a more pronounced appearance, increased activity in uncoordinated patterns, and white lesions all over the body. While the duration of this stage is variable, it typically lasts about one to two months. Death is typically attributed to starvation, as the females have stopped hunting in order to protect their eggs; males often spend more time in the open, making them more likely to be preyed upon.[23]

Intelligence

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Giant Pacific octopus

Octopuses are ranked as the most intelligent invertebrates.[24] Giant Pacific octopuses are commonly kept on display at aquariums due to their size and interesting physiology, and have demonstrated the ability to recognize humans whom they frequently come in contact with. These responses include jetting water, changing body texture, and other behaviors that are consistently demonstrated to specific individuals.[25] They have the ability to solve simple puzzles, open childproof bottles and use tools.[18] The octopus brain has folded lobes (a distinct characteristic of complexity), visual and tactile memory centers. They have about 300 million neurons.[18] They have been known to open tank valves, disassemble expensive equipment, and generally wreak havoc in labs and aquaria.[18] Some researchers even claim that they are capable of motor play[26] and having personalities.[27]

Conservation and climate change

Giant Pacific octopuses are not currently under the protection of Convention on International Trade in Endangered Species of Wild Fauna and Flora or evaluated in the IUCN Red List.[28] The giant Pacific octopus has not been assessed by the Monterey Bay Aquarium Seafood Watch, although other octopus species are listed.[29] Combined with lack of assessment and mislabeling, tracking the species's abundance is nearly impossible. Scientists have relied on catch numbers to estimate stock abundance, but the animals are solitary and difficult to find.[18] DNA techniques have assisted in genetic and phylogenetic analysis of the species' evolutionary past. Following its DNA analysis, the giant Pacific octopus may actually prove to be three subspecies (one in Japan, another in Alaska, and a third in Puget Sound).

In Puget Sound, the Washington Fish and Wildlife Commission adopted rules for protecting the harvest of giant Pacific octopuses at seven sites, after a legal harvest caused a public outcry.[30] Populations in Puget Sound are not considered threatened.

Regardless of these data gaps in abundance estimates, future climate change scenarios may affect these organisms in different ways. Climate change is complex, with predicted biotic and abiotic changes to multiple processes including oxygen limitation, reproduction, ocean acidification, toxins, effects on other trophic levels, and RNA editing.

Oxygen limitation

Octopuses have been found to migrate for a variety of reasons. Using tag and recapture methods, scientists found they move from den to den in response to decreased food availability, change in water quality, increase in predation, or increased population density (or decreased available habitat/den space)[31] Because their blue blood is copper-based (hemocyanin) and not an efficient oxygen carrier, octopuses favor and move toward cooler, oxygen-rich water. This dependency limits octopus habitat, typically to temperate waters 8–12 °C (46–54 °F).[2] If seawater temperatures continue to rise, these organisms may be forced to move to deeper, cooler water.

Each fall in Washington's Hood Canal, a habitat for many octopuses, phytoplankton and macroalgae die and create a dead zone. As these micro-organisms decompose, oxygen is used up in the process and has been measured to be as low as 2 parts per million (ppm). This is a state of hypoxia. Normal levels are measured at 7–9 ppm.[32] Fish and octopuses move from the deep towards the shallow water for more oxygen. Females do not leave, and die with their eggs at nesting sites. Warming seawater temperatures promote phytoplankton growth, and annual dead zones have been found to be increasing in size.[18] To avoid these dead zones, octopuses must move to shallower waters, which may be warmer in temperature and less oxygen-rich, trapping them between two low-oxygen zones.

Reproduction

Increased seawater temperatures also increase metabolic processes. The warmer the water, the faster octopus eggs develop and hatch.[2] After hatching, the paralarvae swim to the surface to join other plankton, where they are often preyed upon by birds, fish, and other plankton feeders. Quicker hatching time may also affect critical timing for food availability.[33] One study found that higher water temperatures accelerated all aspects of reproduction and even shortened lifespan by up to 20%.[34] Other studies concur that warming climate scenarios should result in higher embryo and paralarvae mortalities.[35]

Ocean acidification

The burning of fossil fuels, deforestation, industrialization, and other land-use changes cause increased carbon dioxide levels in the atmosphere. The ocean absorbs an estimated 30% of emitted anthropogenic CO2.[36] As the ocean absorbs CO2, it becomes more acidic and lowers in pH. Ocean acidification lowers available carbonate ions, which is a building block for calcium carbonate (CaCO3). Calcifying organisms use calcium carbonate to produce shells, skeletons, and tests.[37] The prey base that octopuses prefer (crab, clams, scallops, mussels, etc.) are negatively impacted by ocean acidification, and may decrease in abundance. Shifts in available prey may force a change in octopus diets to other, nonshelled organisms.

Because octopuses have hemocyanin as copper-based blood, a small change in pH can reduce oxygen-carrying capacity. A pH change from 8.0 to 7.7 or 7.5 will have life-or-death effects on cephalopods.[18]

Toxins

Researchers have found high concentrations of heavy metals and PCBs in tissues and digestive glands, which may have come from these octopus’ preferred prey, the red rock crab (Cancer productus).[38] These crabs bury themselves in contaminated sediments and eat prey that live nearby.[2] What effects these toxins have on octopuses are unknown, but other exposed animals have been known to show liver damage, changes in immune systems, and death.

Effects on other trophic levels

Potential changes in octopus populations will affect upper and lower trophic levels.[33] Lower trophic levels include all prey items, and may fluctuate inversely with octopus abundance. Higher trophic levels include all predators of octopuses, and may fluctuate with octopus abundance, although many may prey upon a variety of organisms. Protection of other threatened species may affect octopus populations (the sea otter, for example), as they may rely on octopuses for food. Some research suggests that fishing other species has aided octopus populations, by taking out predators and competitors.

RNA editing

Some octopuses exhibit the ability to alter speeds of sodium and potassium ion movement across cell membranes, allowing them to live in very cold water. Researchers at the University of Puerto Rico's Institute of Neurobiology have found that they have altered protein synthesis, and can speed up production of potassium channels in cold water to keep up with sodium ion exchange. They are now looking into whether individuals can alter their protein synthesis in response to changing temperatures, or if this change occurs species-wide, over long-term adaptations. If changes are possible by the individual, these octopuses might be able to adapt quickly to changing climate scenarios.[18]

See also

References

  1. ^ "Distribution of Recent Cephalopoda and implications for Plio-Pleistocene events". Researchgate.net. Retrieved 4 April 2022.
  2. ^ a b c d e f g h i j Cosgrove, James (2009). Super Suckers, The Giant Pacific octopus. BC: Harbour Publishing. ISBN 978-1-55017-466-3.
  3. ^ Cosgrove, J.A. 1987. Aspects of the Natural History of Octopus dofleini, the Giant Pacific Octopus. M.Sc. Thesis. Department of Biology, University of Victoria (Canada), 101 pp.
  4. ^ Smithsonian National Zoological Park: Giant Pacific Octopus Archived 23 February 2014 at the Wayback Machine
  5. ^ O'Shea, S. (2004). "The giant octopus Haliphron atlanticus (Mollusca : Octopoda) in New Zealand waters". New Zealand Journal of Zoology. 31 (1): 7–13. doi:10.1080/03014223.2004.9518353. S2CID 84954869.
  6. ^ O'Shea, S. (2002). "Haliphron atlanticus – a giant gelatinous octopus" (PDF). Biodiversity Update. 5: 1.
  7. ^ a b Norman, M. 2000. Cephalopods: A World Guide. Hackenheim, ConchBooks, p. 214. ISBN 978-3-925919-32-9
  8. ^ High, W.L. (1976). "The Giant Pacific Octopus". U.S. National Marine Fisheries Service, Marine Fisheries Review. 38 (9): 17–22.
  9. ^ McClain, Craig R.; Balk, Meghan A.; Benfield, Mark C.; Branch, Trevor A.; Chen, Catherine; Cosgrove, James; Dove, Alistair D.M.; Gaskins, Lindsay C.; Helm, Rebecca R. (13 January 2015). "Sizing ocean giants: patterns of intraspecific size variation in marine mega fauna". PeerJ. 3: e715. doi:10.7717/peerj.715. ISSN 2167-8359. PMC 4304853. PMID 25649000.
  10. ^ Jereb, Patrizia; Roper, Clyde; Norman, Mark; Finn, Julian (2016). Cephalopods of the World: An annotated and Illustrated Catalogue of cephalopod species known to date (PDF). Food and Agriculture Organization of the United Nations. p. 124. ISBN 978-92-5-107989-8. Retrieved 23 February 2017.
  11. ^ Hartis, Colleen (2 February 2011). "ADW: Enteroctopus dofleini: INFORMATION". Animaldiversity.org. Retrieved 4 April 2022.
  12. ^ "Giant Pacific Octopus". Giant Pacific Octopus - Oceana.
  13. ^ "Giant Pacific octopus facts". www.animalspot.net. 21 February 2018.
  14. ^ "Octopus Eats Shark". Google Video. Retrieved 13 November 2012.
  15. ^ Walla Walla University Marine Invertebrates Key: Giant Pacific Octopus Archived 14 January 2009 at the Wayback Machine
  16. ^ Young, Gayne C. (8 May 2012). "PHOTOS: Pacific Octopus Eats Seagull, First Time Ever Photographed". Outdoor Life.
  17. ^ Sigler, M. F.; L. B. Hulbert; C. R. Lunsford; N. H. Thompson; K. Burek; G. O'Corry-Crowe; A. C. Hirons (24 July 2006). "Diet of Pacific sleeper shark, a potential Steller sea lion predator, in the north-east Pacific Ocean" (PDF). Journal of Fish Biology. 69 (2): 392–405. CiteSeerX 10.1.1.330.8593. doi:10.1111/j.1095-8649.2006.01096.x. Archived from the original (PDF) on 29 May 2010.
  18. ^ a b c d e f g h i j k Courage, Katherine Harmon (2013). Octopus!. USA: The Penguin Group. ISBN 978-1-59184-527-0.
  19. ^ Furuya, Hidetaka; Tsuneki, Kazuhiko (2003). "Biology of Dicyemid Mesozoans". Zoological Science. 20 (5): 519–532. doi:10.2108/zsj.20.519. PMID 12777824. S2CID 29839345.
  20. ^ Scheel, David. "Giant Octopus: Fact Sheet". Alaska Pacific University. Archived from the original on 15 November 2012. Retrieved 13 November 2012.
  21. ^ a b "Giant Pacific Octopus by Shawn Laidlaw". 3 November 2020. Retrieved 28 March 2021.
  22. ^ "Giant Pacific Octopus (Octopus dofleini)". NPCA. Archived from the original on 21 November 2008. Retrieved 13 November 2012.
  23. ^ Anderson, R. C.; Wood, J. B.; Byrne, R. A. (2002). "Octopus Senescence: The Beginning of the End". Journal of Applied Animal Welfare Science. 5 (4): 275–283. CiteSeerX 10.1.1.567.3108. doi:10.1207/S15327604JAWS0504_02. PMID 16221078. S2CID 28355735.
  24. ^ Anderson, R. C. (2005). "How smart are octopuses?". Coral Magazine. 2: 44–48.
  25. ^ Anderson, R. C.; Mather, J. A.; Monette, M. Q.; Zimsen, S. R. M. (2010). "Octopuses (Enteroctopus dofleini) Recognize Individual Humans". Journal of Applied Animal Welfare Science. 13 (3): 261–272. doi:10.1080/10888705.2010.483892. PMID 20563906. S2CID 21910661.
  26. ^ Tzar, Jennifer. "Through the Eye of an Octopus".
  27. ^ Mather, J.A.; Kuba, M.J. (2013). "The cephalopod specialties: complex nervous system, learning and cognition". Canadian Journal of Zoology. 91 (6): 431–449. doi:10.1139/cjz-2013-0009.
  28. ^ "IUCN Red List of Threatened Species. Version 2013.2". Archived from the original on 27 June 2014. Retrieved 12 May 2014.
  29. ^ "Monterey Bay Seafood Watch". Archived from the original on 13 May 2014.
  30. ^ "Giant Pacific Octopus Rulemaking Process". Retrieved 12 May 2014.
  31. ^ Mather, J.A.; Resler, S.; Cosgrove, J.A. (1985). "Activity and Movement patterns of Octopus dofleini". Journal of Marine Behavior and Physiology. 11 (4): 301–14. doi:10.1080/10236248509387055.
  32. ^ Mather, J.A. (2010). Octopus: The Ocean's Intelligent Invertebrate. Portland. London.: J.B. Timber Press. ISBN 978-1-60469-067-5.
  33. ^ a b Andre, J; Haddon, M.; Pecl, G.T. (2010). "Modeling climate-change induced nonlinear thresholds in cephalopod population dynamics". Global Change Biology. 16 (10): 2866–2875. Bibcode:2010GCBio..16.2866A. doi:10.1111/j.1365-2486.2010.02223.x. S2CID 83960161.
  34. ^ Forsythe, J.W.; Hanlon, R.T. (1988). "Effect of temperature on laboratory growth, reproduction, and life span of Octopus bimaculoides" (PDF). Marine Biology. 98 (3): 369–379. doi:10.1007/bf00391113. S2CID 83708339.
  35. ^ Repolho, Tiago (2014). "Developmental and physiological challenges of octopus (Octopus vulgaris) early life stages under ocean warming". Journal of Comparative Physiology B. 184 (1): 55–64. doi:10.1007/s00360-013-0783-y. PMID 24100467. S2CID 8647158.
  36. ^ Guinotte, J.M.; Fabry, V.J. (2008). "Ocean acidification and its potential effects on marine ecosystems". Annals of the New York Academy of Sciences. 1134 (1): 320–342. Bibcode:2008NYASA1134..320G. CiteSeerX 10.1.1.316.7909. doi:10.1196/annals.1439.013. PMID 18566099. S2CID 15009920.
  37. ^ Gazeau, F.; Quiblier, C.; Jansen, J.M.; Gattuso, J.P.; Middelburg, J.J.; Heip, C.H. (2007). "Impact of elevated CO2 on shellfish calcification". Geophysical Research Letters. 34 (7): L07603. Bibcode:2007GeoRL..34.7603G. doi:10.1029/2006gl028554. hdl:20.500.11755/a8941c6a-6d0b-43d5-ba0d-157a7aa05668. S2CID 130190489.
  38. ^ Scheel, D.; Anderson, R. (2012). "Variability in the diet specialization of Enteroctopus dofleini (Cephalopoda: Octopodidae) in the eastern Pacific examined from midden contents". American Malacological Bulletin. 30 (2): 267–279. doi:10.4003/006.030.0206. S2CID 86739608.

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Giant Pacific octopus: Brief Summary

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The giant Pacific octopus (Enteroctopus dofleini, formerly also Octopus apollyon), also known as the North Pacific giant octopus, is a large marine cephalopod belonging to the genus Enteroctopus. Its spatial distribution includes the coastal North Pacific, along California, Oregon, Washington, British Columbia, Alaska, Russia, Japan, and Korean Peninsula. It can be found from the intertidal zone down to 2,000 m (6,600 ft), and is best adapted to cold, oxygen-rich water. It is the largest octopus species, based on a scientific record of a 71-kg (156-lb) individual weighed live.

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Pieuvre géante du Pacifique

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Enteroctopus dofleini

La pieuvre géante du Pacifique (Enteroctopus dofleini) est une espèce de céphalopode de la famille des Octopodidae et vit surtout dans les eaux du Pacifique nord.

Description

 src=
Illustration historique.

La pieuvre géante, d'une couleur rougeâtre, comporte quatre paires de bras qui mesurent environ 3 m de longueur[1] chacun.

Elle vit en moyenne de 3 à 5 ans. Les adultes pèsent de 25 à 43 kg (la plus lourde observée pesait 180 kg). Ses bras peuvent atteindre la taille exceptionnelle de 4,3 mètres[2]. Quelques rares pieuvres de 9 mètres de long (corps + bras) ont déjà été observées dans le Pacifique-Nord. Sa taille bien qu'impressionnante a souvent été exagérée : le Kraken (pieuvre géante de la mythologie scandinave) correspond en fait sans doute aux calmars géants, bien plus gros. Rares sont les pieuvres qui atteignent l'âge adulte.

Ces pieuvres vieillissent de façon très semblable aux humains. Leur système immunitaire devient inopérant, puis le système reproducteur se dégrade, elles deviennent séniles, "ne peuvent plus penser" ni se nourrir[1].

Alimentation

La pieuvre géante se nourrit essentiellement de crustacés et de mollusques tels que les crabes. Mais elle peut aussi manger des poissons, des requins et même d'autres pieuvres[1].

Reproduction

Le mâle place sa semence dans l'orifice de respiration de la femelle puis il meurt[1].

Après fécondation, la femelle accroche ses œufs, de la taille d'un grain de riz, en grappes, au plafond de sa cachette, elle pond à environ 18 mètres de profondeur. Elle les nettoie, les aère et les protège jusqu'à leur éclosion, pendant 150 jours, sans se nourrir, puis elle meurt. Si elle meurt avant, les œufs non surveillés n'ont aucune chance de survie[1].

Les œufs sont ensuite emportés par le courant et finissent par descendre sur le fond, où les petits naissent et vivent[1].

Comportement

 src=
Cette espèce est la star de nombreux aquariums.

C'est un animal curieux, craintif et plutôt paresseux.

La pieuvre géante peut se fondre dans son milieu, se camoufler grâce aux pigments colorés de sa peau, mais elle ne voit qu'en noir et blanc.

Lorsqu'elle se sent en danger, la pieuvre géante libère un nuage d'encre noire qui la masque à l'agresseur, elle peut alors s'échapper [1]. Contrairement aux calmars, elle est dépourvue de griffes. Elle possède 8 bras tous munis de 200 ventouses environ. Grâce à celles-ci, la pieuvre géante peut soulever plus d'une tonne.

Sa relation avec l'homme est spontanément pacifique. Contrairement aux idées reçues, la pieuvre est inoffensive quelle que soit sa taille (à l'exception de la pieuvre à anneaux bleus). Elle est très intelligente et retient les situations pour mieux y réagir plus tard. Mais si elle a déjà été attaquée par l'homme, l'approcher de trop près peut être un réel danger. Il lui arrive parfois de jouer avec les plongeurs, si elle est mise en confiance. Toutefois il convient de prendre quelques précautions : il faut notamment éviter les gestes brusques, car par peur elle pourrait alors mordre de son bec qui ressemble à celui du perroquet, et qui peut aussi cracher du venin (douloureux mais pas dangereux, et utilisé essentiellement pour la chasse et presque jamais comme arme). Son bec est la seule partie dure apparente.

Une pieuvre géante peut facilement se glisser dans un trou ou une crevasse de quelques centimètres seulement, car elle est suffisamment molle pour étirer tout son corps et se glisser dans les plus petites failles, son seul obstacle étant son bec, mais elle sait anticiper par palpation si l'orifice dans lequel elle veut s'introduire sera assez grand pour laisser passer son bec ou non.

Malgré ses 3 cœurs, elle se fatigue très vite et ne peut pratiquer une activité physique que pendant quelques minutes.

Voir aussi

Références taxinomiques

Notes et références
  1. a b c d e f et g Au royaume des pieuvres géantes, Réalisateur: Sigurd Tesche, Documentaire, ARTE, 15 novembre 2010 à 19:55.
  2. (en)Smithsonian National Zoological Park Giant Pacific Octopus

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Pieuvre géante du Pacifique: Brief Summary

provided by wikipedia FR

Enteroctopus dofleini

La pieuvre géante du Pacifique (Enteroctopus dofleini) est une espèce de céphalopode de la famille des Octopodidae et vit surtout dans les eaux du Pacifique nord.

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문어

provided by wikipedia 한국어 위키백과
 src= 언어학 용어에 대해서는 문어 (언어) 문서를 참고하십시오.

문어(文魚; 학명: 'Enteroctopus dofleini', 영어: octopus)는 문어과에 속하는 연체동물이다. 둥근 머리 모양의 몸체에 두 눈이 있고 빨판이 달린 8개의 다리가 입 주변에 달려 있다. 약 300종이 있으며, 문어목(Octopoda)은 오징어, 갑오징어, 앵무조개목(nautiloids)이 속한 두족강으로 분류된다. 대왕문어, 큰태평양문어라고도 한다.

이름

문어는 지역에 따라 대문어, 대팔초어, 물낙지 등으로 불린다. 문어는 중세 국어에서 ‘믠어’라고 불렀다. 한자 표기 文魚는 ‘믠어’를 한자로 빌려적은 취음이고, 한문으로는 팔초어(八梢魚)로 불렸다.

생태

 src=
제주 문어의 산란

문어는 다리길이 4.3 미터 몸무게 15Kg까지 자라며 수명은 대략 3~5년이다. 봄에서 여름에 걸쳐 수심 40~60 미터 해저에 10만개 이상의 알을 낳으며 산란을 마친 암컷은 6개월여 알을 지키다 죽는다. 살아나는 알은 불과 몇개 밖에 되지 않는다. 오징어와 마찬가지로 짝짓기를 한 후에 수명을 다한다.[1] 중국 동해안, 한국, 일본, 캐나다미국의 서해안 등 북태평양 연안에서 서식한다.

문어는 먹물 주머니가 있어 위협을 느끼면 먹물을 뿜고 달아난다. 또한 문어의 피부는 주위 환경에 따라 색상을 바꿀 수 있어 이를 이용해 자신을 보호한다.

문어는 신경계가 주로 다리에 있어서 변신을 잘 할 수 있으며, 지능이 매우 높아 화산폭발을 미리 알고 피하는 것으로 알려져 있다. 거울을 보여주었을 때 자기 자신을 차츰 인식하는 것으로 알려져 있다. 한 실험에서는 통 속에 든 먹이()를 먹기 위해 뚜껑을 돌려 통을 열었다고 한다.

문어가 도구를 사용하는 장면이 수중카메라로 발견되었다. 문어는 코코넛 껍데기를 운반해 은신처를 만드는 무척추동물의 첫사례로 기록되었다.

효능

문어는 타우린이 풍부해, 혈액 내 콜레스테롤을 낮춰주고 피를 맑게 해 혈관에 탄력을 준다. 간의 해독작용을 도와주어 피로 해소에 좋으며, 심장병과 당뇨 등을 예방해준다. 타우린은 망막의 기능을 도와주어 눈 건강에 좋으며, 단백질이 풍부해 다이어트 식품으로 좋다.[2]

이용

문어는 각종 요리에 사용된다. 갓잡은 것을 삶거나 말린 것을 구워 먹는다.

 src=
문어회

문어과에 속하는 종

문어과에 속하는 다른 종들에는 참문어, 주꾸미, 낙지 등이 있다. 한반도의 연안에는 약 50여 종의 문어과 생물이 서식하고 있다.

각주

  1. “해양생물 다양성 정보센터(해양수산부)”. 2018년 10월 29일에 원본 문서에서 보존된 문서. 2008년 1월 20일에 확인함.
  2. “[건강정보] 문어 효능... 콜레스테롤 저하·피로해소·생리불순 개선&심장병·당뇨 예방”. 《미래한국》. 2018년 10월 29일. 2018년 11월 14일에 확인함.
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문어: Brief Summary

provided by wikipedia 한국어 위키백과
 src= 언어학 용어에 대해서는 문어 (언어) 문서를 참고하십시오.

문어(文魚; 학명: 'Enteroctopus dofleini', 영어: octopus)는 문어과에 속하는 연체동물이다. 둥근 머리 모양의 몸체에 두 눈이 있고 빨판이 달린 8개의 다리가 입 주변에 달려 있다. 약 300종이 있으며, 문어목(Octopoda)은 오징어, 갑오징어, 앵무조개목(nautiloids)이 속한 두족강으로 분류된다. 대왕문어, 큰태평양문어라고도 한다.

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Habitat

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van der Land, J. (ed). (2008). UNESCO-IOC Register of Marine Organisms (URMO).
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