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| *Octopoida<br><small>Leach, 1817</small> | *Octopoida<br><small>Leach, 1817</small> | ||
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| FUCK YOU BITCHES!!! | |||
| The '''octopus''' ({{pronEng|ˈɒktəpəs}}, from ] {{Unicode|Ὀκτώπους}}, 'eight-footed',<ref>] from ] ὀκτώποδ-, ὀκτώπους (also ὀκτάποδ- ὀκτάπους) "eight-footed" > ὀκτώ- or ὀκτά- and πόδ-, πούς "foot". Cf. ] χταπόδι <οκταπόδι <οκταπόδιον <ὀκτάπους.</ref> with plural forms: '''octopuses''' {{IPA|}}, '''octopi''' {{IPA|}}, or '''octopodes''' {{IPA|}}, see ]) is a ] of the ] '''Octopoda''' that inhabits many diverse regions of the ], especially ]s. The term may also refer to only those creatures in the ] '']''. In the larger sense, there are around 300 recognized octopus ], which is over one-third of the total number of known cephalopod species. | |||
| ==Biology== | |||
| Octopuses are characterized by their eight ] (as distinct from the ]s found in ] and ]), usually bearing ]s. These arms are a type of ]. Unlike most other cephalopods, the majority of octopuses — those in the suborder most commonly known, ] — have almost entirely soft bodies with no internal ]. They have neither a protective outer ] like the ], nor any vestige of an internal shell or ]s, like cuttlefish or squid. A ], similar in shape to a ]'s beak, is the only hard part of their body. This enables them to squeeze through very narrow slits between underwater rocks, which is very helpful when they are fleeing from ]s or other predatory fish. The octopuses in the less familiar ] suborder have two fins and an internal shell, generally reducing their ability to squeeze into small spaces. | |||
| ]s during ]]] | |||
| Octopuses have a relatively short ], and some species live for as little as six months. Larger species, such as the ], may live for up to five years under suitable circumstances. However, reproduction is a cause of death: males can only live for a few months after mating, and females die shortly after their eggs hatch. They neglect to eat during the (roughly) one month period spent taking care of their unhatched eggs, but they don't die of starvation. Endocrine secretions from the two optic glands are the cause of genetically-programmed death (and if these glands are surgically removed, the octopus may live many months beyond reproduction, until she finally starves). | |||
| Octopuses have three hearts. Two pump blood through each of the two ]s, while the third pumps blood through the body. Octopus ] contains the ]-rich protein ] for transporting ]. Although less efficient under ] than the ]-rich ] of vertebrates, in cold conditions with low oxygen pressure, hemocyanin oxygen transportation is more efficient than hemoglobin oxygen transportation. The hemocyanin is dissolved in the ] instead of being bound in ]s and gives the blood a blue color. Octopuses draw water into their mantle cavity where it passes through its gills. As ], octopuses have gills that are finely divided and vascularized outgrowths of either the outer or the inner body surface. | |||
| ===Intelligence=== | |||
| {{main|Cephalopod intelligence}} | |||
| ] (''Octopus cyanea'') observing its surroundings]] | |||
| Octopuses are highly ], probably more intelligent than any other order of ]s. The exact extent of their intelligence and learning capability is much debated among biologists,<ref name = "ham"/><ref name="doug"> By Doug Stewart. In: National Wildlife. Feb/Mar 1997, vol.35 no.2. | |||
| </ref><ref name="denizen"> </ref><ref> Slate.</ref> but maze and ] experiments have shown that they do have both ] and ]. Their short lifespans limit the amount they can ultimately learn. There has been much speculation to the effect that almost all octopus behaviors are independently learned rather than instinct-based, although this remains largely unproven. They learn almost no behaviors from their parents, with whom young octopuses have very little contact. | |||
| An octopus has a highly complex ], only part of which is localized in its ]. Two-thirds of an octopus's ]s are found in the nerve cords of its arms, which have a remarkable amount of autonomy. Octopus arms show a wide variety of complex ] actions arising on at least three different levels of the nervous system. Some octopuses, such as the ], will move their arms in ways that emulate the movements of other ]. | |||
| In laboratory experiments, octopuses can be readily trained to distinguish between different shapes and patterns. They have been reported to practice ],<ref></ref> although the validity of these findings is widely contested on a number of grounds.<ref name="ham">. By Garry Hamilton.</ref><ref name="doug"> By Doug Stewart. In: National Wildlife. Feb/Mar 1997, vol.35 no.2. | |||
| </ref> Octopuses have also been observed in what some have described as play: repeatedly releasing bottles or toys into a circular current in their aquariums and then catching them.<ref>. By Dr. Jennifer Mather, Department of Psychology and Neuroscience, ] and Roland C. Anderson, The ]. </ref> Octopuses often break out of their aquariums and sometimes into others in search of food. They have even boarded ]s and opened holds to eat crabs.<ref name=denizen></ref> | |||
| In some countries, octopuses are on the list of ] on which surgery may not be performed without ]. In the UK, cephalopods such as octopuses are regarded as ''honorary vertebrates'' under the ] and other ] legislation, extending to them protections not normally afforded to invertebrates.<ref></ref> | |||
| A common belief is that when stressed, an octopus may begin to eat its own arms. However, limited research conducted in this area has revealed that the cause of this abnormal behavior, called ], may be a virus that attacks the octopus's ]. Thus this behavior may be more correctly labeled as a ].{{Fact|date=February 2007}} | |||
| ===Defense=== | |||
| ] | |||
| ] (''Hapalochlaena lunulata'')]] | |||
| An octopus's main (primary) defense is to hide, either not to be seen at all, or not to be detected as an octopus.<ref name=behaviour>Hanlon, R.T. & J.B. Messenger 1996. ''Cephalopod Behaviour''. Cambridge University Press, Cambridge.</ref> Octopuses have several secondary defenses (defenses they use once they have been seen by a predator). The most common secondary defense is fast escape. Other defenses include the use of ]s, ], and ]. | |||
| ] | |||
| Most octopuses can eject a thick blackish ink in a large cloud to aid in escaping from predators. The main colouring agent of the ink is melanin, which is the same chemical that gives humans their hair and ]. This ink cloud is thought to dull ], which is particularly useful for evading predators that are dependent on smell for hunting, such as ]s. Ink clouds of some species might serve as pseudomorphs, or decoys that the predator attacks instead.<ref>Caldwell, R. L. (2005). "An Observation of Inking Behavior Protecting Adult ''Octopus bocki'' from Predation by Green Turtle (''Chelonia mydas'') Hatchlings." ''Pacific Science'' '''59'''(1): 69–72.</ref> | |||
| An octopus's camouflage is aided by certain specialized skin cells which can change the apparent color, opacity, and reflectiveness of the epidermis. ]s contain yellow, orange, red, brown, or black pigments; most species have three of these colors, while some have two or four. Other color-changing cells are reflective ]s, and ]s (white).<ref>{{cite web | url = http://www.dnr.sc.gov/marine/sertc/species_month.htm | title = Tales from the Cryptic: The Common Atlantic Octopus | accessdate = 2006-07-27 | author = Meyers, Nadia|publisher = Southeastern Regional Taxonomic Center}}</ref> This color-changing ability can also be used to communicate with or warn other octopuses. The very venomous ] becomes bright yellow with blue rings when it is provoked. Octopuses can use muscles in the skin to change the texture of their mantle in order to achieve a greater camouflage. In some species the mantle can take on the spiky appearance of seaweed, or the scraggly, bumpy texture of a rock, among other disguises. However in some species skin anatomy is limited to relatively patternless shades of one color, and limited skin texture. It is thought that octopuses that are day-active and/or live in complex habitats such as coral reefs have evolved more complex skin than their nocturnal and/or sand-dwelling relatives.<ref name=behaviour /> | |||
| When under attack, some octopuses can perform arm ], in a similar manner to the way ]s and other ]s detach their tails. The crawling arm serves as a distraction to would-be predators. | |||
| A few species, such as the ], have a fourth defense mechanism. They can combine their highly flexible bodies with their color changing ability to accurately mimic other, more dangerous animals such as ], ], and ]s.<ref>Norman, M.D., J. Finn & T. Tregenza (2001). {{PDFlink|}} ''Proceedings of the Royal Society'' '''268''': 1755–1758.</ref><ref>Norman, M.D. & F.G.Hochberg (2005). The "Mimic Octopus" (''Thaumoctopus mimicus'' n. gen. et sp.), a new octopus from the tropical Indo-West Pacific (Cephalopoda: Octopodidae). ''Molluscan Research'' '''25''': 57–70. </ref> | |||
| ===Reproduction=== | |||
| When octopuses reproduce, males use a specialized arm called a ] to insert ]s (packets of sperm) into the female's mantle cavity. The hectocotylus in benthic octopuses is usually the third right arm. Males die within a few months of mating. In some species, the female octopus can keep the sperm alive inside her for weeks until her eggs are mature. After they have been fertilized, the female lays about 200,000 eggs (this figure dramatically varies between families, genera, species and also individuals). The female hangs these eggs in strings from the ceiling of her lair, or individually attaches them to the ] depending on the species. The female cares for the eggs, guarding them against predators, and gently blowing currents of water over them so that they get enough oxygen. The female does not eat during the roughly one-month period spent taking care of the unhatched eggs. At around the time the eggs hatch, the mother dies and the young larval octopuses spend a period of time drifting in clouds of ], where they feed on ]s, larval ]s and larval ] until they are ready to sink down to the bottom of the ocean, where the cycle repeats itself. In some deeper dwelling species, the young do not go through this period. This is a dangerous time for the larval octopuses; as they become part of the plankton cloud they are vulnerable to many plankton eaters. | |||
| ===Sensation=== | |||
| ]'']] | |||
| Octopuses have keen eyesight. Although their slit-shaped ]s might be expected to afflict them with ], it appears that this is not a problem in the light levels in which an octopus typically hunts. Surprisingly, they do not appear to have ], although they can distinguish the ] of light. Attached to the brain are two special organs, called ]s, that allow the octopus to sense the orientation of its body relative to horizontal. An ] response keeps the octopus's eyes oriented so that the pupil slit is always horizontal. | |||
| Octopuses also have an excellent ]. An octopus's suction cups are equipped with ] so that the octopus can ] what it is touching. The arms contain ] sensors so that the octopus knows whether its arms are stretched out. However, the octopus has a very poor ] sense. The tension receptors are not sufficient for the octopus brain to determine the position of the octopus's body or arms. (It is not clear that the octopus brain would be capable of processing the large amount of information that this would require; the flexibility of an octopus's arms is much greater than that of the limbs of vertebrates, which devote large areas of ] to the processing of proprioceptive inputs.) As a result, the octopus does not possess ]; that is, it does not form a ] of the overall shape of the object it is handling. It can detect local texture variations, but cannot integrate the information into a larger picture.<ref name="wells">Wells. Martin John. ''Octopus: physiology and behaviour of an advanced invertebrate''. London : ] ; New York : distributed in the U.S.A. by Halsted Press, 1978.</ref> | |||
| The neurological autonomy of the arms means that the octopus has great difficulty learning about the detailed effects of its motions. The brain may issue a high-level command to the arms, but the nerve cords in the arms execute the details. There is no neurological path for the brain to receive feedback about just how its command was executed by the arms; the only way it knows just what motions were made is by observing the arms visually.<ref name="wells"/> | |||
| ===Locomotion=== | |||
| ] | |||
| Octopuses move about by crawling or swimming. Their main means of slow travel is crawling, with some swimming. Jet propulsion is their fastest means of locomotion, followed by swimming and bipedal walking.<ref></ref> | |||
| They crawl by walking on their arms, usually on many at once, on both solid and soft surfaces, while supported in water. In 2005 it was reported that some octopuses (''Abdopus aculeatus'' and ''Amphioctopus marginatus'' under current taxonomy) can walk on two arms, while at the same time resembling plant matter.<ref> </ref> This form of locomotion allows these octopuses to move quickly away from a potential predator while possibly not triggering that predator's search image for octopus (food).<ref></ref> Octopuses lack bones and are extremely vulnerable to predators. | |||
| Octopuses swim by expelling a jet of water from a contractile ], and aiming it via a muscular ]. | |||
| ===Size=== | |||
| {{see also|Cephalopod size}} | |||
| The ], ''Enteroctopus dofleini'', is often cited as the largest octopus species. Adults usually weigh around 15 kg (33 lb), with an arm span of up to 4.3 m (14 ft).<ref name="FONZ"></ref> The largest specimen of this species to be scientifically documented was an animal with a live mass of 71 kg (156.5 lb).<ref>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.</ref> The alternative contender is the ], ''Haliphron atlanticus'', based on a 61 kg (134 lb) carcass estimated to have a live mass of 75 kg (165 lb).<ref>O'Shea, S. 2004. The giant octopus ''Haliphron atlanticus'' (Mollusca : Octopoda) in New Zealand waters. ''New Zealand Journal of Zoology'' '''31'''(1): 7-13.</ref><ref>O'Shea, S. 2002. ''Haliphron atlanticus'' — a giant gelatinous octopus. ''Biodiversity Update'' '''5''': 1.</ref> However, there are a number of questionable size records that would suggest ''E. dofleini'' is the largest of all octopus species by a considerable margin;<ref name=norman03>Norman, M. 2000. ''Cephalopods: A World Guide''. Hackenheim, ConchBooks, p. 214.</ref> one such record is of a specimen weighing 272 kg (600 lb) and having an arm span of 9 m (30 ft).<ref>High, W.L. 1976. The giant Pacific octopus. ''U.S. National Marine Fisheries Service, Marine Fisheries Review'' '''38'''(9): 17-22.</ref> | |||
| == Terminology == | |||
| There are three forms of the plural of ''octopus''; namely, ''octopuses'', ''octopi'', and ''octopodes''. Currently, ''octopuses'' is the most common form in the UK as well as the US; ''octopodes'' is rare, and ''octopi'' is often objected to.<ref>Peters, Pam (2004). ''The Cambridge Guide to English Usage''. Cambridge: Cambridge University Press. ISBN 0-521-62181-X, p. 388.</ref> | |||
| The '']'' (2004 update<ref> (subscription required). Retrieved October 22, 2007.</ref>) lists ''octopuses'', ''octopi'' and ''octopodes'' (in that order); it labels ''octopodes'' "rare", and notes that ''octopi'' derives from the mistaken assumption that ''{{unicode|octōpūs}}'' is a ] ] ], which it is not. Rather, it is (Latinized) ], from ''{{unicode|oktṓpous}}'' {{polytonic|(ὀκτώπους)}}, ] masculine, whose plural is ''{{unicode|oktṓpodes}}'' ({{polytonic|ὀκτώποδες}}). If the word were native to Latin, it would be ''{{unicode|octōpēs}}'' ('eight-foot') and the plural ''{{unicode|octōpedes}}'', analogous to ''{{unicode|centipedes}}'' and ''{{unicode|mīllipedes}}'', as the plural form of ''{{unicode|pēs}}'' ('foot') is ''{{unicode|pedes}}''. In modern, informal Greek, it is called ''{{unicode|khtapódi}}'' {{Polytonic|(χταπόδι)}}, gender neuter, with plural form ''{{unicode|khtapódia}}'' {{Polytonic|(χταπόδια)}}. | |||
| ''Chambers 21st Century Dictionary''<ref>. Retrieved October 19, 2007.</ref> and the ''Compact Oxford Dictionary''<ref> Retrieved October 19, 2007.</ref> list only ''octopuses'', although the latter notes that ''octopodes'' is "still occasionally used"; the ] has 29 instances of ''octopuses'', 11 of ''octopi'' and 4 of ''octopodes''. ''Merriam-Webster 11th Collegiate Dictionary'' lists ''octopuses'' and ''octopi'', in that order; ''Webster's New World College Dictionary'' lists ''octopuses'', ''octopi'' and ''octopodes'' (in that order). | |||
| '']'' states that "the only acceptable plural in English is ''octopuses,''" and that ''octopi'' is misconceived and ''octopodes'' ]. | |||
| The term ''octopod'' (plural ''octopods'' or ''octopodes'') is taken from the ] Octopoda but has no classical equivalent. The collective form ''octopus'' is usually reserved for animals consumed for food. | |||
| == Relationship to humans == | |||
| {{cephalopod topics}} | |||
| ] Lima, Peru.]] | |||
| Ancient peoples of the ] were cognizant of the octopus, as evinced by certain artworks and designs of prehistory. For example, a stone carving found in the archaeological recovery from ] ] ] at ] has a depiction of a fisherman carrying an octopus.<ref></ref> | |||
| The ] people of ancient ] worshipped the sea and its animals; moreover, octopuses were often depicted in their art.<ref>Berrin, Katherine & Larco Museum. ''The Spirit of Ancient Peru:Treasures from the ].'' New York: ], 199 7.</ref> | |||
| === In mythology === | |||
| The ] ] relates that the present cosmos is only the last of a series, having arisen in stages from the wreck of the previous universe. In this account, the octopus is the lone survivor of the previous, alien universe.<ref name=Dixon>{{cite book | title = The Mythology of All Races | subtitle = Oceanic | volume = 9 | last = Dixon | first = Roland Burrage | year = 1916 | publisher = Marshall Jones | page = 15 | authorlink = Roland Burrage Dixon}}</ref> | |||
| ]]] | |||
| === As food === | |||
| Many species of octopus are eaten as food by human cultures around the world. The arms and sometimes other parts of the body are prepared in various ways, often depending on the species being eaten. | |||
| Care must be taken to boil the octopus properly, to rid it of slime and the smell, as well as any residual ink. | |||
| ]s]]Octopus is a common ingredient in ], including ], ], and ]. Some small species are sometimes ] as a novelty and ] (mostly in ]). Similarly, a live octopus may be sliced up and the legs eaten while still squirming, which they continue to do for some minutes. | |||
| Octopus are also eaten regularly in ], many of the popular dishes being Asian in origin. Locally known by their Hawaiian or Japanese name, ("he'e" and "tako" respectively) octopus are also a popular catch used as fish bait. | |||
| Octopus is also a common food in ]. In ], ] (fair style octopus) is a local delicacy. Restaurants which specialize or serve this dish are known as pulperías. | |||
| {{Wikibookspar|Cookbook|Octopus}} | |||
| According to the USDA Nutrient Database (2007), cooked octopus contains approximately 139 calories per three ounce portion, and is a source of ], ], ], ], and ].<ref></ref> | |||
| === As pets === | |||
| ] through a thin crack.]] | |||
| Though octopuses can be difficult to keep in captivity, some people keep them as pets. Octopuses often escape even from supposedly secure tanks, due to their problem solving skills, mobility and lack of rigid structure. | |||
| The variation in size and life span among octopus species makes it difficult to know how long a new specimen can naturally be expected to live. That is, a small octopus may be just born or may be an adult, depending on the species. By selecting a well-known species, such as the ], one can choose a small octopus (around the size of a ]) and be confident that it is young with a full life ahead of it. | |||
| Octopuses are also quite strong for their size. Octopuses kept as pets have been known to open the covers of their aquariums and survive for a time in the air in order to get to a nearby feeder tank and gorge themselves on the fish there. They have also been known to catch and kill some species of ]s.<ref>, from The Octopus Show by ]</ref> | |||
| ==Classification== | |||
| {{Wikispecies|Octopoda}} | |||
| {{Wikibookspar|Dichotomous Key|Octopoda}} | |||
| {{commons}} | |||
| ] | |||
| *Class ] | |||
| **Subclass ]: nautilus | |||
| **Subclass ] | |||
| ***Superorder ]: ], ] | |||
| ***Superorder ] | |||
| ****Order ]: Vampire Squid | |||
| ****'''Order Octopoda''' | |||
| *****Genus †'']'' <small>('']'')</small> | |||
| *****Genus †'']'' <small>('']'')</small> | |||
| *****Genus †'']'' <small>('']'')</small> | |||
| *****Suborder ]: finned ] octopus | |||
| ******Family ]: umbrella octopus | |||
| ******Family ] | |||
| ******Family ] | |||
| *****Suborder ] | |||
| ******Family ]: ] | |||
| ******Family ]: gelatinous octopus | |||
| ******Family ]: benthic octopus | |||
| ******Family ]: Glass Octopus | |||
| ******Superfamily ] | |||
| *******Family ]: Seven-arm Octopus | |||
| *******Family ]: argonauts | |||
| *******Family ]: Tuberculate Pelagic Octopus | |||
| *******Family ]: blanket octopus | |||
| ==See also== | |||
| *] | |||
| *] | |||
| * Octopus, a ] game. | |||
| * A six-armed octopus, or "]", was found in March 2008 by British researchers.<ref name="yahoonews">{{Cite web|url=http://news.yahoo.com/s/afp/20080303/sc_afp/sciencebritainanimalhexapusoffbeat|title=Six-legged 'hexapus' claimed as world first in Britain|date=2008-03-03|accessdate=2008-03-03}}</ref> Its subnormal complement of arms was attributed to a ]. | |||
| ==References== | |||
| {{reflist|2}} | |||
| ==External links== | |||
| {{sisterlinks|octopus}} | |||
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Revision as of 13:46, 10 October 2008
For other uses, see Octopus (disambiguation).
| Octopus | |
|---|---|
| |
| The Common Octopus, Octopus vulgaris. | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Cephalopoda |
| Subclass: | Coleoidea |
| Superorder: | Octopodiformes |
| Order: | Octopoda Leach, 1818 |
| Suborders | |
|
†Pohlsepia (incertae sedis) | |
| Synonyms | |
| |
FUCK YOU BITCHES!!!