The Giant Pacific octopus of the North Pacific is one of the largest marine cephalopods on the planet. For more fascinating facts about octopus… Subclass Coleoidea 1.2.1. The venom appears to be able to penetrate the skin without a puncture, given prolonged contact. Global Biodiversity Information Facility. The dorsal side of the disc grows upwards and forms the embryo, with a shell gland on its dorsal surface, gills, mantle and eyes. Abdopus aculeatus mostly lives in near-shore seagrass beds. [141], Japanese erotic art, shunga, includes ukiyo-e woodblock prints such as Katsushika Hokusai's 1814 print Tako to ama (The Dream of the Fisherman's Wife), in which an ama diver is sexually intertwined with a large and a small octopus. Researchers have identified impressions of eight arms, two eyes, and possibly an ink sac. Some species are adapted to the cold, ocean depths. [157][158] Animal welfare groups have objected to this practice on the basis that octopuses can experience pain. The California two-spot octopus has had its genome sequenced, allowing exploration of its molecular adaptations. The Hawaiian day octopus (Octopus cyanea) lives on coral reefs; argonauts drift in pelagic waters. Males become senescent and die a few weeks after mating. [148], All species are venomous, but only blue-ringed octopuses have venom that is lethal to humans. The physical principle behind this is that the force required to accelerate the water through the orifice produces a reaction that propels the octopus in the opposite direction. [152], Octopus fisheries exist around the world with total catches varying between 245,320 and 322,999 metric tons from 1986 to 1995. [63] A complex hydraulic mechanism releases the sperm from the spermatophore, and it is stored internally by the female. Basal species, the Cirrina, have stout gelatinous bodies with webbing that reaches near the tip of their arms, and two large fins above the eyes, supported by an internal shell. [70] Octopus reproductive organs mature due to the hormonal influence of the optic gland but result in the inactivation of their digestive glands, typically causing the octopus to die from starvation. [34][35], Octopuses have a closed circulatory system, in which the blood remains inside blood vessels. It was described in 1829 by the French zoologist Georges Cuvier, who supposed it to be a parasitic worm, naming it as a new species, Hectocotylus octopodis. [22] The arms can be described based on side and sequence position (such as L1, R1, L2, R2) and divided into four pairs. Species Octopus bimaculatus. Muscles in the skin change the texture of the mantle to achieve greater camouflage. The true octopuses are members of the genus Octopus, a large group of widely distributed shallow-water cephalopods. [43][44], During osmoregulation, fluid is added to the pericardia of the branchial hearts. [118], The scientific name Octopoda was first coined and given as the order of octopuses in 1818 by English biologist William Elford Leach,[119] who classified them as Octopoida the previous year. This claim was widely disbelieved until the 19th century. Superorder Octopodiformes 1.2.2.1. [22] Octopuses may also use the statocyst to hear sound. [129], The cladograms are based on Sanchez et al., 2018, who created a molecular phylogeny based on mitochondrial and nuclear DNA marker sequences.[121]. The testis in males and the ovary in females bulges into the gonocoel and the gametes are released here. This is likely the result of abundant food supplies combined with limited den sites. [117] A gram-negative bacterium, Vibrio lentus, has been found to cause skin lesions, exposure of muscle and death of octopuses in extreme cases. A battle with an octopus appears in Victor Hugo's book Toilers of the Sea, inspiring other works such as Ian Fleming's Octopussy. [162][163] Other zoologists thought it a spermatophore; the German zoologist Heinrich Müller believed it was "designed" to detach during copulation. Previously, it was named Octopus dofleini. Octopus bimaculatus: information (1) Species Octopus briareus. Aspects of the Natural History of, "Quantitative Analysis of Culture Using Millions of Digitized Books", "Smithsonian National Zoological Park: Giant Pacific Octopus", "Understanding octopus growth: patterns, variability and physiology", "Octopuses and Relatives: Locomotion, Crawling", "Kinematic decomposition and classification of octopus arm movements", "The morphology and adhesion mechanism of, "Feel the light – sight independent negative phototactic response in octopus' arms", "Finned Deep-sea Octopuses, Grimpoteuthis spp", "Octopuses and Relatives: Locomotion, jet propulsion", "The control of ventilatory and cardiac responses to changes in ambient oxygen tension and oxygen demand in, "An Embodied View of Octopus Neurobiology", "Dynamic model of the octopus arm. Species Octopus aculeatus. [165] Having independently evolved mammal-like intelligence, octopuses have been compared to hypothetical intelligent extraterrestrials. Species Octopus aegina. [53] This would explain pupils shaped like the letter U, the letter W, or a dumbbell, as well as explaining the need for colourful mating displays. "Interspecific Evaluation of Octopus Escape Behavior", "Armed but not dangerous: Is the octopus really the invertebrate intellect of the sea", "Giant Octopus – Mighty but Secretive Denizen of the Deep", "What behavior can we expect of octopuses? [104], A "moving rock" trick involves the octopus mimicking a rock and then inching across the open space with a speed matching the movement in the surrounding water, allowing it to move in plain sight of a predator. [81][82] Octopuses feed on shelled molluscs either by forcing the valves apart, or by drilling a hole in the shell to inject a nerve toxin. Fleshy papillae or cirri are found along the bottom of the arms, and the eyes are more developed. In most species, fertilisation occurs in the mantle cavity. [27] Lacking skeletal support, the arms work as muscular hydrostats and contain longitudinal, transverse and circular muscles around a central axial nerve. [81] Major items in the diet of the giant Pacific octopus include bivalve molluscs such as the cockle Clinocardium nuttallii, clams and scallops and crustaceans such as crabs and spider crabs. The octopus is a marine mollusk and a member of the class Cephalopoda, more commonly called cephalopods. Species Octopus adamsi. For example, a 2.4-metre (8 ft) Pacific octopus, said to be nearly perfectly camouflaged, "lunged" at a diver and "wrangled" over his camera before it let go. This fascinating creature was discovered in 1998 off the coast of Sulawesi in Indonesia on the bottom of a muddy river mouth. No, octopuses are not oceanic “elitists.” Class merely refers to the third tier of classification. When a sucker attaches to a surface, the orifice between the two structures is sealed. It is not known precisely what contribution learning makes to adult octopus behaviour. [71]:276–277 Experimental removal of both optic glands after spawning was found to result in the cessation of broodiness, the resumption of feeding, increased growth, and greatly extended lifespans. In 2015 a team in Italy built soft-bodied robots able to crawl and swim, requiring only minimal computation. The octopus can squeeze through tiny gaps; even the larger species can pass through an opening close to 2.5 cm (1 in) in diameter. Adults usually weigh around 15 kg (33 lb), with an arm span of up to 4.3 m (14 ft). Octopus arms can move and sense largely autonomously without intervention from the animal's central nervous system. Octopuses have a complex nervous system and excellent sight, and are among the most intelligent and behaviourally diverse of all invertebrates. It has been commonly studied among the octopus species. Each sucker is usually circular and bowl-like and has two distinct parts: an outer shallow cavity called an infundibulum and a central hollow cavity called an acetabulum, both of which are thick muscles covered in a protective chitinous cuticle. [147], Octopuses generally avoid humans, but incidents have been verified. [171] In 2017 a German company made an arm with a soft pneumatically controlled silicone gripper fitted with two rows of suckers. Another diver recorded the encounter on video. 1. It is able to grasp objects such as a metal tube, a magazine, or a ball, and to fill a glass by pouring water from a bottle. [22] An optic gland creates hormones that cause the octopus to mature and age and stimulate gamete production. The Pacific octopus was recently re-classified. In the UK from 1993 to 2012, the common octopus (Octopus vulgaris) was the only invertebrate protected under the Animals (Scientific Procedures) Act 1986. [27] Food is broken down and is forced into the oesophagus by two lateral extensions of the esophageal side walls in addition to the radula. The ink is thought to reduce the efficiency of olfactory organs, which would aid evasion from predators that employ smell for hunting, such as sharks. This material is based upon work supported by the [26] The cirrate species are often free-swimming and live in deep-water habitats. [172], Soft-bodied eight-limbed order of molluscs, This article is about the order of cephalopod. Cephalopod, any member of the class Cephalopoda of the phylum Mollusca, a small group of highly advanced and organized, exclusively marine animals. ... ADW doesn't cover all species in the world, nor does it include all the latest scientific information about organisms we describe. This would be Cephalopoda. [133] The Kraken are legendary sea monsters of giant proportions said to dwell off the coasts of Norway and Greenland, usually portrayed in art as a giant octopus attacking ships. [22] Most of the body is made of soft tissue allowing it to lengthen, contract, and contort itself. [13] The New Oxford American Dictionary (3rd Edition, 2010) lists "octopuses" as the only acceptable pluralisation, and indicates that "octopodes" is still occasionally used, but that "octopi" is incorrect. Scientists have recognized more than 300 Octopus species. [24][25] The bulbous and hollow mantle is fused to the back of the head and is known as the visceral hump; it contains most of the vital organs. [36][37][38] In cold conditions with low oxygen levels, haemocyanin transports oxygen more efficiently than haemoglobin. The octopus has a completely merged head and foot with a ring of arms surrounding the head. This … [36][37] [121] The incirrate octopuses (the majority of species) lack the cirri and paired swimming fins of the cirrates. [111] Octopuses can replace lost limbs. In 2004, analysis of the Bayesian classification problem has shown that there are some theoretical reasons for the apparently unreasonable efficacy of … (See cephalopod.) [64]:74 The female aerates the eggs and keeps them clean; if left untended, many eggs will not hatch. Like other cephalopods, the octopus is bilaterally symmetric with two eyes and a beak, with its mouth at the center point of the eight limbs. [50], Like other cephalopods, octopuses can distinguish the polarisation of light. The molecular analysis of the octopods shows that the suborder Cirrina (Cirromorphida) and the superfamily Argonautoidea are paraphyletic and are broken up; these names are shown in quotation marks and italics on the cladogram. This moves the body slowly. [96][105], Aside from humans, octopuses may be preyed on by fishes, seabirds, sea otters, pinnipeds, cetaceans, and other cephalopods. Species Octopus abaculus. Class Cephalopoda 1.1. Other creatures, such as fish, crabs, molluscs and echinoderms, often share the den with the octopus, either because they have arrived as scavengers, or because they have survived capture. [22], Some species differ in form from the typical octopus body shape. The male argonaut is minute by comparison and has no shell. [78], Octopuses bring captured prey back to the den where they can eat it safely. When resting, around 41% of an octopus's oxygen absorption is through the skin. [74], Most species are solitary when not mating,[75] though a few are known to occur in high densities and with frequent interactions, signaling, mate defending and eviction of individuals from dens. The siphon is used both for respiration and for locomotion, by expelling a jet of water. Learn more about cephalopods in this article. The term Octopoda was first coined by English biologist William Elford Leach in 1818. They live in the oceans around the world. The suckers allow the octopus to anchor itself or to manipulate objects. The scientific Latin term octopus was derived from Ancient Greek ὀκτώπους, a compound form of ὀκτώ (oktō, "eight") and πούς (pous, "foot"), itself a variant form of ὀκτάπους, a word used for example by Alexander of Tralles (c. 525–605) for the common octopus. [69], Octopuses have a relatively short life expectancy; some species live for as little as six months. [41] Water flow over the gills correlates with locomotion, and an octopus can propel its body when it expels water out of its siphon. He picks up a spermatophore from his spermatophoric sac with the hectocotylus, inserts it into the female's mantle cavity, and deposits it in the correct location for the species, which in the giant Pacific octopus is the opening of the oviduct. [39] Extensive connective tissue lattices support the respiratory muscles and allow them to expand the respiratory chamber. © 2020 Regents of the University of Michigan. From there it is transferred to the gastrointestinal tract, which is mostly suspended from the roof of the mantle cavity by numerous membranes. This causes death by respiratory failure leading to cerebral anoxia. Octopus briareus: information (1) Species Octopus cyanea. The small octopuses are common in tropical and subtropical coral reefs and tide pools of the Pacific and Indian Oceans, ranging from southern Japan to Australia. [79] Octopuses rarely engage in interspecific cooperative hunting with fish as their partners. [104], Octopuses can create distracting patterns with waves of dark coloration across the body, a display known as the "passing cloud". Help us improve the site by taking our survey. 1987. All octopods are venomous, but only the small blue-ringed octopus is known to be deadly to humans. ", "What's Odd About That Octopus? The neurological autonomy of the arms means the octopus has great difficulty learning about the detailed effects of its motions. [62] The hectocotylus in benthic octopuses is usually the third right arm, which has a spoon-shaped depression and modified suckers near the tip. ", "The great escape: Inky the octopus legs it to freedom from aquarium", "Coconut shelter: evidence of tool use by octopuses", "Tales from the Cryptic: The Common Atlantic Octopus", "Octopuses and Relatives: Predators and Defenses", "An Observation of Inking Behavior Protecting Adult, "Even Severed Octopus Arms Have Smart Moves", "Dynamic mimicry in an Indo-Malayan octopus", "Pathogens and immune response of cephalopods", "Genus-level phylogeny of cephalopods using molecular markers: current status and problematic areas", "A Broad Brush History of the Cephalopoda", "Trade-off between transcriptome plasticity and genome evolution in cephalopods", "Caroli Linnaei Systema naturae sistens regna tria naturae", "Why Mark Zuckerberg Octopus Cartoon Evokes 'Nazi Propaganda,' German Paper Apologizes", "8-Foot Octopus Wrestles Diver Off California Coast, Rare Encounter Caught on Camera", "Tentacles of venom: new study reveals all octopuses are venomous", "What makes blue-rings so deadly? [21], The octopus is bilaterally symmetrical along its dorso-ventral axis; the head and foot are at one end of an elongated body and function as the anterior (front) of the animal. The sac is close enough to the funnel for the octopus to shoot out the ink with a water jet. During gastrulation, the margins of this grow down and surround the yolk, forming a yolk sac, which eventually forms part of the gut. Two spermatophores are transferred in this way; these are about one metre (yard) long, and the empty ends may protrude from the female's mantle. Image from Wikimedia Commons. [107] The Atlantic white-spotted octopus (Callistoctopus macropus) turns bright brownish red with oval white spots all over in a high contrast display. Colour vision appears to vary from species to species, for example being present in O. aegina but absent in O. Around 300 species are recognised, and the order is grouped within the class Cephalopoda with squids, cuttlefish, and nautiloids. [86] A study of this behaviour led to the suggestion that the two rearmost appendages may be more accurately termed "legs" rather than "arms". Octopuses have three hearts; a systemic heart that circulates blood around the body and two branchial hearts that pump it through each of the two gills. Such severed arms remain sensitive to stimuli and move away from unpleasant sensations. [19][20] The smallest species is Octopus wolfi, which is around 2.5 cm (1 in) and weighs less than 1 g (0.035 oz). Octopods make up over one-third of … Free and Open Access to Biodiversity Data. One such species is the giant Pacific octopus, in which courtship is accompanied, especially in the male, by changes in skin texture and colour. [22], The reproduction of octopuses has been studied in only a few species. [46][47] It has a highly complex nervous system, only part of which is localised in its brain, which is contained in a cartilaginous capsule. [35] Although several species are known to live at bathyal and abyssal depths, there is only a single indisputable record of an octopus in the hadal zone; a species of Grimpoteuthis (dumbo octopus) photographed at 6,957 m (22,825 ft). [35] In addition, the internal shell of incirrates is either present as a pair of stylets or absent altogether. I. Biomechanics of the octopus reaching movement", "Color Discrimination Conditioning in Two Octopus, "Octopus vision, it's in the eye (or skin) of the beholder", "Study proposes explanation for how cephalopods see colour, despite black and white vision", "Odd pupils let 'colorblind' octopuses see colors", "Cephalopod Ink: Production, Chemistry, Functions and Applications", "Giant Pacific Octopus (Enteroctopus dofleini) Care Manual", "Absurd Creature of the Week: The Beautiful Octopus Whose Sex Is All About Dismemberment", "Octopuses were thought to be solitary until a social species turned up", "Octopus Senescence: The Beginning of the End", Journal of Applied Animal Welfare Science, "First in situ observation of Cephalopoda at hadal depths (Octopoda: Opisthoteuthidae: Grimpoteuthis sp. [106] The blue rings of the highly venomous blue-ringed octopus are hidden in muscular skin folds which contract when the animal is threatened, exposing the iridescent warning. Classification. [36][37], The systemic heart has muscular contractile walls and consists of a single ventricle and two atria, one for each side of the body. [90][99][100] They have even boarded fishing boats and opened holds to eat crabs. They can grow bigger and lives longer than any other octopus species, in fact, the record size for this species is a monster slaying 30 feet (9.1 meters) long! The soft body can rapidly alter its shape, enabling octopuses to squeeze through small gaps. [83][82] It used to be thought that the hole was drilled by the radula, but it has now been shown that minute teeth at the tip of the salivary papilla are involved, and an enzyme in the toxic saliva is used to dissolve the calcium carbonate of the shell. Before reaching the branchial heart, each branch of the vena cava expands to form renal appendages which are in direct contact with the thin-walled nephridium. The systemic heart is inactive when the animal is swimming and thus it tires quickly and prefers to crawl. [104] An octopus may spend 40% of its time hidden away in its den. In most species, the male uses a specially adapted arm to deliver a bundle of sperm directly into the female's mantle cavity, after which he becomes senescent and dies, while the female deposits fertilised eggs in a den and cares for them until they hatch, after which she also dies. A gland attached to the sac produces the ink, and the sac stores it. [22] Octopus species that produce larger eggs – including the southern blue-ringed, Caribbean reef, California two-spot, Eledone moschata[67] and deep sea octopuses – do not have a paralarval stage, but hatch as benthic animals similar to the adults. As progress is made, other arms move ahead to repeat these actions and the original suckers detach. [57], The ink sac of an octopus is located under the digestive gland. Octopus - Classification. [167], Due to their intelligence, octopuses are listed in some countries as experimental animals on which surgery may not be performed without anesthesia, a protection usually extended only to vertebrates. [63] In colder waters, such as those off of Alaska, it may take as much as 10 months for the eggs to completely develop. To do this they use specialised skin cells which change the appearance of the skin by adjusting its colour, opacity, or reflectivity. Actually, they get the name from their beautiful blue-ringed markings all over the body. Classification of Animal Kingdom is based on various fundamental features like – 1. Additional support has come from the Marisla Foundation, UM College of Literature, Science, and the Arts, Museum of Zoology, and Information and Technology Services. This decreases to 33% when it swims, as more water flows over the gills; skin oxygen uptake also increases. Octopus Species – Read The Article There are more than 300 different species of Octopus that have been identified but there may be many more we haven’t evaluated yet. [64]:74–75[68], In the argonaut (paper nautilus), the female secretes a fine, fluted, papery shell in which the eggs are deposited and in which she also resides while floating in mid-ocean. ADW doesn't cover all species in the world, nor does it include all the latest scientific information about organisms we describe. Octopuses, squids and cuttlefish belong to the clade Coleoidea. Other colour-changing cells are reflective iridophores and white leucophores. [164], Octopuses offer many possibilities in biological research, including their ability to regenerate limbs, change the colour of their skin, behave intelligently with a distributed nervous system, and make use of 168 kinds of protocadherins (humans have 58), the proteins that guide the connections neurons make with each other.

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