Octopus

Octopus

Overview
The octopus is a cephalopod
Cephalopod
A cephalopod is any member of the molluscan class Cephalopoda . These exclusively marine animals are characterized by bilateral body symmetry, a prominent head, and a set of arms or tentacles modified from the primitive molluscan foot...

 mollusc of the order
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...

 Octopoda. Octopuses have two eyes and four pairs of arms, and like other cephalopods they are bilaterally symmetric. An octopus has a hard beak, with its mouth at the center point of the arms. Octopuses have no internal or external skeleton (although some species have a vestigial remnant of a shell inside their mantle
Mantle (mollusc)
The mantle is a significant part of the anatomy of molluscs: it is the dorsal body wall which covers the visceral mass and usually protrudes in the form of flaps well beyond the visceral mass itself.In many, but by no means all, species of molluscs, the epidermis of the mantle secretes...

), allowing them to squeeze through tight places.
Discussion
Ask a question about 'Octopus'
Start a new discussion about 'Octopus'
Answer questions from other users
Full Discussion Forum
 
Unanswered Questions
Recent Discussions
Encyclopedia
The octopus is a cephalopod
Cephalopod
A cephalopod is any member of the molluscan class Cephalopoda . These exclusively marine animals are characterized by bilateral body symmetry, a prominent head, and a set of arms or tentacles modified from the primitive molluscan foot...

 mollusc of the order
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...

 Octopoda. Octopuses have two eyes and four pairs of arms, and like other cephalopods they are bilaterally symmetric. An octopus has a hard beak, with its mouth at the center point of the arms. Octopuses have no internal or external skeleton (although some species have a vestigial remnant of a shell inside their mantle
Mantle (mollusc)
The mantle is a significant part of the anatomy of molluscs: it is the dorsal body wall which covers the visceral mass and usually protrudes in the form of flaps well beyond the visceral mass itself.In many, but by no means all, species of molluscs, the epidermis of the mantle secretes...

), allowing them to squeeze through tight places. Octopuses are among the most intelligent and behaviorally flexible of all invertebrate
Invertebrate
An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...

s.

The octopus inhabits many diverse regions of the ocean
Ocean
An ocean is a major body of saline water, and a principal component of the hydrosphere. Approximately 71% of the Earth's surface is covered by ocean, a continuous body of water that is customarily divided into several principal oceans and smaller seas.More than half of this area is over 3,000...

, including coral reef
Coral reef
Coral reefs are underwater structures made from calcium carbonate secreted by corals. Coral reefs are colonies of tiny living animals found in marine waters that contain few nutrients. Most coral reefs are built from stony corals, which in turn consist of polyps that cluster in groups. The polyps...

s, pelagic waters, and the ocean floor. They have numerous strategies for defending themselves against predators, including the expulsion of ink, the use of camouflage and deimatic displays, their ability to jet quickly through the water, and their ability to hide. An octopus trails its eight arms behind it as it swims. All octopuses are venomous, but only one group, the blue-ringed octopus
Blue-ringed octopus
The blue-ringed octopuses are three octopus species that live in tide pools in the Pacific Ocean, from Japan to Australia . They are currently recognized as one of the world's most venomous marine animals...

es, is known to be deadly to humans.

There are around 300 recognized octopus species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

, which is over one-third of the total number of known cephalopod species. The term octopus may also be used to refer only to those creatures in the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 Octopus.

Biology



Octopuses are characterized by their eight arms
Cephalopod arm
A cephalopod arm is distinct from a tentacle, though the terms are often used interchangeably.Generally, cephalopod arms have suckers along most of their length, as opposed to tentacles, which have suckers only near their ends. Octopuses have eight arms and no tentacles, while squid and cuttlefish...

, usually bearing suction cup
Suction cup
A suction cup, also sometimes known as a sucker is an object that uses negative fluid pressure of air or water to adhere to nonporous surfaces. They exist both as artificially created devices, and as anatomical traits of some animals such as octopi and squid.The working face of the suction cup has...

s. The arms of octopuses are often distinguished from the pair of feeding tentacle
Tentacle
A tentacle or bothrium is one of usually two or more elongated flexible organs present in animals, especially invertebrates. The term may also refer to the hairs of the leaves of some insectivorous plants. Usually, tentacles are used for feeding, feeling and grasping. Anatomically, they work like...

s found in squid
Squid
Squid are cephalopods of the order Teuthida, which comprises around 300 species. Like all other cephalopods, squid have a distinct head, bilateral symmetry, a mantle, and arms. Squid, like cuttlefish, have eight arms arranged in pairs and two, usually longer, tentacles...

 and cuttlefish
Cuttlefish
Cuttlefish are marine animals of the order Sepiida. They belong to the class Cephalopoda . Despite their name, cuttlefish are not fish but molluscs....

. Both types of limbs are muscular hydrostat
Muscular hydrostat
A muscular hydrostat is a biological structure found in animals. It is used to manipulate items or to move its host about and consists mainly of muscles with no skeletal support...

s. Unlike most other cephalopods, the majority of octopuses – those in the suborder most commonly known, Incirrina – have almost entirely soft bodies with no internal skeleton
Skeleton
The skeleton is the body part that forms the supporting structure of an organism. There are two different skeletal types: the exoskeleton, which is the stable outer shell of an organism, and the endoskeleton, which forms the support structure inside the body.In a figurative sense, skeleton can...

. They have neither a protective outer shell like the nautilus
Nautilus
Nautilus is the common name of marine creatures of cephalopod family Nautilidae, the sole extant family of the superfamily Nautilaceae and of its smaller but near equal suborder, Nautilina. It comprises six living species in two genera, the type of which is the genus Nautilus...

, nor any vestige of an internal shell or bone
Bone
Bones are rigid organs that constitute part of the endoskeleton of vertebrates. They support, and protect the various organs of the body, produce red and white blood cells and store minerals. Bone tissue is a type of dense connective tissue...

s, like cuttlefish or squid. A beak
Beak
The beak, bill or rostrum is an external anatomical structure of birds which is used for eating and for grooming, manipulating objects, killing prey, fighting, probing for food, courtship and feeding young...

, similar in shape to a parrot
Parrot
Parrots, also known as psittacines , are birds of the roughly 372 species in 86 genera that make up the order Psittaciformes, found in most tropical and subtropical regions. The order is subdivided into three families: the Psittacidae , the Cacatuidae and the Strigopidae...

'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 morays
Moray eel
Moray eels are cosmopolitan eels of the family Muraenidae. The approximately 200 species in 15 genera are almost exclusively marine, but several species are regularly seen in brackish water and a few, for example the freshwater moray can sometimes be found in freshwater...

 or other predatory fish. The octopuses in the less familiar Cirrina suborder have two fins and an internal shell, generally reducing their ability to squeeze into small spaces. These cirrate species are often free-swimming and live in deep-water habitats, while incirrate octopus species are found in reefs and other shallower seafloor habitats.

Octopuses have a relatively short life expectancy
Life expectancy
Life expectancy is the expected number of years of life remaining at a given age. It is denoted by ex, which means the average number of subsequent years of life for someone now aged x, according to a particular mortality experience...

, and some species live for as little as six months. Larger species, such as the Giant Pacific Octopus, 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, eventually dying of starvation. In a scientific experiment, it was discovered that removal of both optic glands after spawning results in cessation of broodiness, resumption of feeding, increased growth, and greatly extended life-span.
Octopuses have three heart
Heart
The heart is a myogenic muscular organ found in all animals with a circulatory system , that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...

s. Two branchial heart
Branchial heart
Branchial hearts are myogenic accessory pumps found in coleoid cephalopods that supplement the action of the main, systemic heart. Each consists of a single chamber and they are always paired, being located at the base of the gills. They pump blood through the gills via the afferent branchial veins...

s pump blood through each of the two gill
Gill
A gill is a respiratory organ found in many aquatic organisms that extracts dissolved oxygen from water, afterward excreting carbon dioxide. The gills of some species such as hermit crabs have adapted to allow respiration on land provided they are kept moist...

s, while the third pumps blood through the body. Octopus blood
Blood
Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....

 contains the copper
Copper
Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...

-rich protein hemocyanin
Hemocyanin
Hemocyanins are respiratory proteins in the form of metalloproteins containing two copper atoms that reversibly bind a single oxygen molecule . Oxygenation causes a color change between the colorless Cu deoxygenated form and the blue Cu oxygenated form...

 for transporting oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...

. Although less efficient under normal conditions
Standard conditions for temperature and pressure
Standard condition for temperature and pressure are standard sets of conditions for experimental measurements established to allow comparisons to be made between different sets of data...

 than the iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...

-rich hemoglobin
Hemoglobin
Hemoglobin is the iron-containing oxygen-transport metalloprotein in the red blood cells of all vertebrates, with the exception of the fish family Channichthyidae, as well as the tissues of some invertebrates...

 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 plasma
Blood plasma
Blood plasma is the straw-colored liquid component of blood in which the blood cells in whole blood are normally suspended. It makes up about 55% of the total blood volume. It is the intravascular fluid part of extracellular fluid...

 instead of being carried within red blood cell
Red blood cell
Red blood cells are the most common type of blood cell and the vertebrate organism's principal means of delivering oxygen to the body tissues via the blood flow through the circulatory system...

s and gives the blood a bluish color. Octopuses draw water into their mantle cavity where it passes through its gills. As mollusks
Mollusca
The Mollusca , common name molluscs or mollusksSpelled mollusks in the USA, see reasons given in Rosenberg's ; for the spelling mollusc see the reasons given by , is a large phylum of invertebrate animals. There are around 85,000 recognized extant species of molluscs. Mollusca is the largest...

, octopuses have gills that are finely divided and vascularized outgrowths of either the outer or the inner body surface.

Intelligence



Octopuses are highly intelligent
Intelligence
Intelligence has been defined in different ways, including the abilities for abstract thought, understanding, communication, reasoning, learning, planning, emotional intelligence and problem solving....

, likely more so than any other order of invertebrate
Invertebrate
An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...

s. The exact extent of their intelligence and learning capability is much debated among biologists, but maze and problem-solving
Problem solving
Problem solving is a mental process and is part of the larger problem process that includes problem finding and problem shaping. Consideredthe most complex of all intellectual functions, problem solving has been defined as higher-order cognitive process that requires the modulation and control of...

 experiments have shown that they show evidence of a memory system that can store both short-
Short-term memory
Short-term memory is the capacity for holding a small amount of information in mind in an active, readily available state for a short period of time. The duration of short-term memory is believed to be in the order of seconds. A commonly cited capacity is 7 ± 2 elements...

 and long-term memory
Long-term memory
Long-term memory is memory in which associations among items are stored, as part of the theory of a dual-store memory model. According to the theory, long term memory differs structurally and functionally from working memory or short-term memory, which ostensibly stores items for only around 20–30...

. It is not known precisely what contribution learning makes to adult octopus behavior. Young octopuses learn almost no behaviors from their parents, with whom they have very little contact.

An octopus has a highly complex nervous system
Nervous system
The nervous system is an organ system containing a network of specialized cells called neurons that coordinate the actions of an animal and transmit signals between different parts of its body. In most animals the nervous system consists of two parts, central and peripheral. The central nervous...

, only part of which is localized in its brain
Brain
The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...

. Two-thirds of an octopus's neuron
Neuron
A neuron is an electrically excitable cell that processes and transmits information by electrical and chemical signaling. Chemical signaling occurs via synapses, specialized connections with other cells. Neurons connect to each other to form networks. Neurons are the core components of the nervous...

s are found in the nerve cords of its arms, which have limited functional autonomy. Octopus arms show a variety of complex reflex
Reflex
A reflex action, also known as a reflex, is an involuntary and nearly instantaneous movement in response to a stimulus. A true reflex is a behavior which is mediated via the reflex arc; this does not apply to casual uses of the term 'reflex'.-See also:...

 actions that persist even when they have no input from the brain. Unlike vertebrates, the complex motor skills of octopuses are not organized in their brain using an internal somatotopic map
Somatotopic arrangement
Somatotopic arrangement is the maintenance of spatial organization within the central nervous system. For example, sensory information maintains its structure throughout the spinal cord and brain.Densely innervated areas of the body occupy large regions of the cortex....

 of its body, as is the motor system in vertebrates Some octopuses, such as the mimic octopus
Mimic Octopus
The Mimic Octopus, Thaumoctopus mimicus, is a species of octopus that has a strong ability to mimic other creatures. It grows up to 60 cm in length. Its normal colouring consists of brown and white stripes or spots....

, will move their arms in ways that emulate the shape and movements of other sea creatures
Marine biology
Marine biology is the scientific study of organisms in the ocean or other marine or brackish bodies of water. Given that in biology many phyla, families and genera have some species that live in the sea and others that live on land, marine biology classifies species based on the environment rather...

.

In laboratory experiments, octopuses can be readily trained to distinguish between different shapes and patterns. They have been reported to practice observational learning
Observational learning
Observational learning is a type of learning that occurs as a function of observing, retaining and replicating novel behavior executed by others...

, although the validity of these findings is widely contested on a number of grounds. 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. Octopuses often break out of their aquariums and sometimes into others in search of food. They have even boarded fishing boats and opened holds to eat crabs.

In some countries, octopuses are on the list of experimental animals
Animal testing
Animal testing, also known as animal experimentation, animal research, and in vivo testing, is the use of non-human animals in experiments. Worldwide it is estimated that the number of vertebrate animals—from zebrafish to non-human primates—ranges from the tens of millions to more than 100 million...

 on which surgery may not be performed without anesthesia
Anesthesia
Anesthesia, or anaesthesia , traditionally meant the condition of having sensation blocked or temporarily taken away...

. In the UK, cephalopods such as octopuses are regarded as honorary vertebrates under the Animals (Scientific Procedures) Act 1986
Animals (Scientific Procedures) Act 1986
The Animals Act 1986 is an Act of the Parliament of the United Kingdom passed in 1986, which regulates the use of laboratory animals in the UK. The Act permits experiments to be carried out on animals, including procedures involving vivisection, if certain criteria are met...

 and other cruelty to animals
Cruelty to animals
Cruelty to animals, also called animal abuse or animal neglect, is the infliction of suffering or harm upon non-human animals, for purposes other than self-defense. More narrowly, it can be harm for specific gain, such as killing animals for food or for their fur, although opinions differ with...

 legislation, extending to them protections not normally afforded to invertebrates.

The octopus is the only invertebrate which has been shown to use tools
Tool use by animals
Tools are used by some animals, particularly primates, to perform simple tasks such as the acquisition of food, or grooming. Originally thought to be a skill only possessed by humans, tool use requires some level of intelligence. Primates have been observed exploiting sticks and stones to...

. At least four specimens of the Veined Octopus (Amphioctopus marginatus) have been witnessed retrieving discarded coconut
Coconut
The coconut palm, Cocos nucifera, is a member of the family Arecaceae . It is the only accepted species in the genus Cocos. The term coconut can refer to the entire coconut palm, the seed, or the fruit, which is not a botanical nut. The spelling cocoanut is an old-fashioned form of the word...

 shells, manipulating them, and then reassembling them to use as shelter. This discovery was documented in the journal Current Biology
Current Biology
Current Biology is a scientific journal that covers all areas of biology, especially molecular biology, cell biology, genetics, neurobiology, ecology and evolutionary biology. The journal is published twice a month and includes peer-reviewed research articles, various types of review articles, as...

and has also been caught on video.

Defense



An octopus's main (primary) defense is to hide, either not to be seen at all, or not to be detected as an octopus. 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 ink sac
Ink sac
With the exception of nocturnal and very deep water cephalopods, all coeloids which dwell in light conditions have an ink sac, which can be used to expel a cloud of dark ink to confuse predators. This sac is a muscular bag which originated as an extension of the hind gut...

s, camouflage
Camouflage
Camouflage is a method of concealment that allows an otherwise visible animal, military vehicle, or other object to remain unnoticed, by blending with its environment. Examples include a leopard's spotted coat, the battledress of a modern soldier and a leaf-mimic butterfly...

, and autotomising limbs
Autotomy
Autotomy or self amputation is the act whereby an animal severs one or more of its own appendages, usually as a self-defense mechanism designed to elude a predator's grasp...

.

Most octopuses can eject a thick blackish ink
Cephalopod ink
Cephalopod ink is a dark pigment released into water by most species of cephalopod, usually as an escape mechanism. All cephalopods, with the exception of the Nautilidae and the species of octopus belonging to the suborder Cirrina, are able to release ink....

 in a large cloud to aid in escaping from predators. The main coloring agent of the ink is melanin
Melanin
Melanin is a pigment that is ubiquitous in nature, being found in most organisms . In animals melanin pigments are derivatives of the amino acid tyrosine. The most common form of biological melanin is eumelanin, a brown-black polymer of dihydroxyindole carboxylic acids, and their reduced forms...

, which is the same chemical that gives humans their hair and skin color
Human skin color
Human skin color is primarily due to the presence of melanin in the skin. Skin color ranges from almost black to white with a pinkish tinge due to blood vessels underneath. Variation in natural skin color is mainly due to genetics, although the evolutionary causes are not completely certain...

. This ink cloud is thought to reduce the efficiency of olfactory organs, which would aid an octopus's evasion from predators that employ smell
Olfaction
Olfaction is the sense of smell. This sense is mediated by specialized sensory cells of the nasal cavity of vertebrates, and, by analogy, sensory cells of the antennae of invertebrates...

 for hunting, such as shark
Shark
Sharks are a type of fish with a full cartilaginous skeleton and a highly streamlined body. The earliest known sharks date from more than 420 million years ago....

s. Ink clouds of some species might serve as pseudomorphs, or decoys that the predator attacks instead.

An octopus's camouflage is aided by certain specialized skin cells which can change the apparent color, opacity, and reflectiveness of the epidermis. Chromatophore
Chromatophore
Chromatophores are pigment-containing and light-reflecting cells found in amphibians, fish, reptiles, crustaceans, and cephalopods. They are largely responsible for generating skin and eye colour in cold-blooded animals and are generated in the neural crest during embryonic development...

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 iridophores, and leucophores (white). This color-changing ability can also be used to communicate with or warn other octopuses. The very venomous blue-ringed octopus
Blue-ringed octopus
The blue-ringed octopuses are three octopus species that live in tide pools in the Pacific Ocean, from Japan to Australia . They are currently recognized as one of the world's most venomous marine animals...

 becomes bright yellow with blue rings when it is provoked. Octopuses can use muscles in the skin to change the texture of their mantle 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.

When under attack, some octopuses can perform arm autotomy
Autotomy
Autotomy or self amputation is the act whereby an animal severs one or more of its own appendages, usually as a self-defense mechanism designed to elude a predator's grasp...

, in a similar manner to the way skink
Skink
Skinks are lizards belonging to the family Scincidae. Together with several other lizard families, including Lacertidae , they comprise the superfamily or infraorder Scincomorpha...

s and other lizard
Lizard
Lizards are a widespread group of squamate reptiles, with nearly 3800 species, ranging across all continents except Antarctica as well as most oceanic island chains...

s detach their tails. The crawling arm serves as a distraction to would-be predators.

A few species, such as the Mimic Octopus
Mimic Octopus
The Mimic Octopus, Thaumoctopus mimicus, is a species of octopus that has a strong ability to mimic other creatures. It grows up to 60 cm in length. Its normal colouring consists of brown and white stripes or spots....

, 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 lionfish
Pterois
Pterois is a genus of venomous marine fish found mostly in the Indo-Pacific, known collectively as the lionfish. Pterois is characterized by red, white and black stripes, showy pectoral fins and venomous spiky tentacles. Pterois are classified into fifteen different species, but Pterois radiata,...

, sea snakes
Sea Snakes
Sea Snakes were a Canadian indie rock band, formed in 2002 and disbanded in 2005. The band consisted of vocalist and guitarist Jimmy McIntyre, guitarist Kristian Galberg, bassist and saxophonist Jeremy Strachan, keyboardist Shaw-Han Liem and drummer Nathan Lawr.Strachan played in the defunct band...

, and eel
Eel
Eels are an order of fish, which consists of four suborders, 20 families, 111 genera and approximately 800 species. Most eels are predators...

s.

Reproduction


When octopuses reproduce, males use a specialized arm called a hectocotylus
Hectocotylus
A hectocotylus is one of the arms of the male of most kinds of cephalopods that is modified in various ways to effect the fertilization of the female's eggs. It is a specialized, extended muscular hydrostat used to store spermatophores, the male gametophore...

 to insert spermatophore
Spermatophore
A spermatophore or sperm ampulla is a capsule or mass created by males of various animal species, containing spermatozoa and transferred in entirety to the female's ovipore during copulation...

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 substrate
Substrate (biology)
In biology a substrate is the surface a plant or animal lives upon and grows on. A substrate can include biotic or abiotic materials and animals. For example, encrusting algae that lives on a rock can be substrate for another animal that lives on top of the algae. See also substrate .-External...

 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 hunt during the roughly one-month period spent taking care of the unhatched eggs and may ingest some of her own arms for sustenance. At around the time the eggs hatch, the mother leaves the lair and is too weak to defend herself from predators like cod, often succumbing to their attacks. The young larval octopuses spend a period of time drifting in clouds of plankton
Plankton
Plankton are any drifting organisms that inhabit the pelagic zone of oceans, seas, or bodies of fresh water. That is, plankton are defined by their ecological niche rather than phylogenetic or taxonomic classification...

, where they feed on copepod
Copepod
Copepods are a group of small crustaceans found in the sea and nearly every freshwater habitat. Some species are planktonic , some are benthic , and some continental species may live in limno-terrestrial habitats and other wet terrestrial places, such as swamps, under leaf fall in wet forests,...

s, larval crab
Crab
True crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" , or where the reduced abdomen is entirely hidden under the thorax...

s and larval starfish until they are ready to descend to the ocean bottom, where the cycle repeats. This is a dangerous time for the larval octopuses; in the plankton cloud they are vulnerable to plankton eaters. In some deeper dwelling species, the young do not go through this period.

Sensation



Octopuses have keen eyesight. Octopuses, like other cephalopods, can distinguish the polarization of light. Color vision
Color vision
Color vision is the capacity of an organism or machine to distinguish objects based on the wavelengths of the light they reflect, emit, or transmit...

 appears to vary from species to species, being present in Octopus aegina but absent in Octopus vulgaris. Attached to the brain are two special organs, called statocyst
Statocyst
The statocyst is a balance sensory receptor present in some aquatic invertebrates, including bivalves, cnidarians, echinoderms, cephalopods, and crustaceans. A similar structure is also found in Xenoturbella. The statocyst consists of a sac-like structure containing a mineralised mass and numerous...

s, that allow the octopus to sense the orientation of its body relative to horizontal. An autonomic
Autonomic nervous system
The autonomic nervous system is the part of the peripheral nervous system that acts as a control system functioning largely below the level of consciousness, and controls visceral functions. The ANS affects heart rate, digestion, respiration rate, salivation, perspiration, diameter of the pupils,...

 response keeps the octopus's eyes oriented so that the pupil slit is always horizontal.

Octopuses also have an excellent sense of touch
Somatosensory system
The somatosensory system is a diverse sensory system composed of the receptors and processing centres to produce the sensory modalities such as touch, temperature, proprioception , and nociception . The sensory receptors cover the skin and epithelia, skeletal muscles, bones and joints, internal...

. An octopus's suction cups are equipped with chemoreceptors so that the octopus can taste
Taste
Taste is one of the traditional five senses. It refers to the ability to detect the flavor of substances such as food, certain minerals, and poisons, etc....

 what it is touching. The arms contain tension
Tension (mechanics)
In physics, tension is the magnitude of the pulling force exerted by a string, cable, chain, or similar object on another object. It is the opposite of compression. As tension is the magnitude of a force, it is measured in newtons and is always measured parallel to the string on which it applies...

 sensors so that the octopus knows whether its arms are stretched out. However, the octopus has a very poor proprioceptive
Proprioception
Proprioception , from Latin proprius, meaning "one's own" and perception, is the sense of the relative position of neighbouring parts of the body and strength of effort being employed in movement...

 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 cerebral cortex
Cerebral cortex
The cerebral cortex is a sheet of neural tissue that is outermost to the cerebrum of the mammalian brain. It plays a key role in memory, attention, perceptual awareness, thought, language, and consciousness. It is constituted of up to six horizontal layers, each of which has a different...

 to the processing of proprioceptive inputs.) As a result, the octopus does not possess stereognosis
Stereognosis
Stereognosis is the ability to perceive and recognize the form of an object using cues from texture, size, spatial properties, and temperature...

; that is, it does not form a mental image
Mental image
A mental image is an experience that, on most occasions, significantly resembles the experience of perceiving some object, event, or scene, but occurs when the relevant object, event, or scene is not actually present to the senses...

 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.

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.

Octopuses appear to have limited hearing.

Locomotion



Octopuses move about by crawling or swimming. Their main means of slow travel is crawling, with some swimming. Jet propulsion
Jet propulsion
Jet propulsion is motion produced by passing a jet of fluid in the opposite direction to the direction of motion. By conservation of momentum, the moving body is propelled in the opposite direction to the jet....

 is their fastest means of locomotion, followed by swimming and walking.

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 (Adopus aculeatus
Abdopus
Abdopus is a genus of octopuses in the family Octopodidae.-Species:* Abdopus abaculus* Abdopus aculeatus* Abdopus capricornicus* Abdopus horridus* Abdopus tonganus* Abdopus undulatus-References:...

and Amphioctopus marginatus
Veined Octopus
Amphioctopus marginatus, also known as the coconut octopus and veined octopus, is a medium-sized cephalopod belonging to the genus Amphioctopus. It is found in tropical waters of the western Pacific Ocean...

under current taxonomy) can walk on two arms, while at the same time resembling plant matter. 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). Some species of octopuses can crawl out of the water for a short period, which they may do between tide pool
Tide pool
Tide pools are rocky pools by oceans that are filled with seawater. Many of these pools exist as separate entities only at low tide.Tide pools are habitats of uniquely adaptable animals that have engaged the special attention of naturalists and marine biologists, as well as philosophical...

s while hunting crustacea or gastropods or to escape predators.

Octopuses swim by expelling a jet of water from a contractile mantle
Mantle (mollusc)
The mantle is a significant part of the anatomy of molluscs: it is the dorsal body wall which covers the visceral mass and usually protrudes in the form of flaps well beyond the visceral mass itself.In many, but by no means all, species of molluscs, the epidermis of the mantle secretes...

, and aiming it via a muscular siphon.

Predation


Bottom-dwelling octopuses eat mainly crabs, polychaete worms, and other molluscs such as whelk
Whelk
Whelk, also spelled welk or even "wilks", is a common name used to mean one or more kinds of sea snail. The species, genera and families referred to using this common name vary a great deal from one geographic area to another...

s and clam
Clam
The word "clam" can be applied to freshwater mussels, and other freshwater bivalves, as well as marine bivalves.In the United States, "clam" can be used in several different ways: one, as a general term covering all bivalve molluscs...

s. Open-ocean octopuses eat mainly prawns, fish and other cephalopods. They usually inject their prey with a paralysing saliva before dismembering it into small pieces with their beaks. Octopuses feed on shelled molluscs either by using force, or by drilling a hole in the shell, injecting a secretion into the hole, and then extracting the soft body of the mollusc.

Size




The Giant Pacific Octopus, 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). The largest specimen of this species to be scientifically documented was an animal with a live mass of 71 kg (156.5 lb). The alternative contender is the Seven-arm Octopus
Seven-arm Octopus
The Seven-arm Octopus is the largest known species of octopus based on scientific records, with a total estimated length of 4 m and weight of 75 kg...

, Haliphron atlanticus, based on a 61 kg (134 lb) carcass estimated to have a live mass of 75 kg (165 lb). 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; one such record is of a specimen weighing 272 kg (600 lb) and having an arm span of 9 m (30 ft).

Etymology and pluralization


The term "octopus" is from Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...

 ὀκτάπους (oktapous, "eight-footed"), with traditional plural forms "octopuses" from English grammar and "octopodes" from the Greek. Currently, "octopuses" is the most common form in both the US
American English
American English is a set of dialects of the English language used mostly in the United States. Approximately two-thirds of the world's native speakers of English live in the United States....

 and the UK
British English
British English, or English , is the broad term used to distinguish the forms of the English language used in the United Kingdom from forms used elsewhere...

. The term "octopod" (plural: "octopods" or "octopodes") is taken from the taxonomic order
Taxonomic order
Taxonomic sequence is a sequence followed in listing of taxa which aids ease of use and roughly reflects the evolutionary relationships among the taxa...

 Octopoda but has no classical equivalent. The collective plural "octopus" is usually reserved for animals consumed for food.

Some authorities find that octopi is an objectionable hypercorrection
Hypercorrection
In linguistics or usage, hypercorrection is a non-standard usage that results from the over-application of a perceived rule of grammar or a usage prescription...

, feeling that the form arose from the incorrect assumption that "octopus" is a Latin form. However, "octopus" is a Scientific Latin
New Latin
The term New Latin, or Neo-Latin, is used to describe the Latin language used in original works created between c. 1500 and c. 1900. Among other uses, Latin during this period was employed in scholarly and scientific publications...

 word, while the Latinized spelling of the Greek word is "octopous." The word came into English via Neo-Latin rather than directly from Greek. Perhaps reflecting the amount of scientific literature that was written in Neo-Latin, the Latinate plural remains more common than the original Greek one: The British National Corpus
British National Corpus
The British National Corpus is a 100-million-word text corpus of samples of written and spoken English from a wide range of sources. It was compiled as a general corpus in the field of corpus linguistics...

 has 29 instances of "octopuses", 11 of "octopi", and 4 of "octopodes".

The Oxford English Dictionary
Oxford English Dictionary
The Oxford English Dictionary , published by the Oxford University Press, is the self-styled premier dictionary of the English language. Two fully bound print editions of the OED have been published under its current name, in 1928 and 1989. The first edition was published in twelve volumes , and...

(2008 Draft Revision) lists "octopuses", "octopi", and "octopodes" (in that order), labelling "octopodes" 'rare' and noting that "octopi" derives from the apprehension that octōpus is a second declension Latin noun
Second declension
The second declension is a category of nouns in Latin and Greek with similar case formation. In particular, these nouns are thematic, with an original o in most of their forms. In Classical Latin the short o of the nominative and accusative singular became u.Both Latin and Greek have two basic...

, though it is not. The book further maintains that if the word were native to Latin, it would be third declension
Third declension
The third declension is a category of nouns in Latin and Greek with broadly similar case formation — diverse stems, but similar endings. In contrast with the first- and second-declension endings, those of the third declension lack a theme vowel and so are called athematic.One distinguishing...

 octōpēs (plural: octōpedes) after the pattern of pēs ("foot", plural pedēs). The original Latin word for octopus and other similar species is polypus, from Greek polýpous (πολύπους, "many-footed"); again, usually the inappropriate plural polypī is used instead of polypodēs.

Fowler's Modern English Usage
Fowler's Modern English Usage
A Dictionary of Modern English Usage , by Henry Watson Fowler , is a style guide to British English usage, pronunciation, and writing...

states that 'the only acceptable plural in English is "octopuses"', that "octopi" is 'misconceived', and "octopodes" 'pedantic'. Chambers 21st Century Dictionary and the Compact Oxford Dictionary list only "octopuses", although the latter notes that "octopodes" is 'still occasionally used'. The descriptivist Merriam-Webster 11th Collegiate Dictionary lists "octopuses" and "octopi" in that order; likewise, Webster's New World College Dictionary lists in order "octopuses", "octopi", and "octopodes".

In modern Greek
Modern Greek
Modern Greek refers to the varieties of the Greek language spoken in the modern era. The beginning of the "modern" period of the language is often symbolically assigned to the fall of the Byzantine Empire in 1453, even though that date marks no clear linguistic boundary and many characteristic...

, the word is χταπόδι (khtapódi; plural: χταπόδια, khtapódia), from Byzantine
Medieval Greek
Medieval Greek, also known as Byzantine Greek, is the stage of the Greek language between the beginning of the Middle Ages around 600 and the Ottoman conquest of the city of Constantinople in 1453. The latter date marked the end of the Middle Ages in Southeast Europe...

 ὀκταπόδιον (oktapódion) derived from the Classical Greek variant ὀκτάπους (oktápous).

Relationship to humans



Ancient peoples of the Mediterranean were aware of the octopus, as evidenced by certain artworks and designs of prehistory. For example, a stone carving found in the archaeological recovery from Bronze Age
Bronze Age
The Bronze Age is a period characterized by the use of copper and its alloy bronze as the chief hard materials in the manufacture of some implements and weapons. Chronologically, it stands between the Stone Age and Iron Age...

 Minoan
Minoan civilization
The Minoan civilization was a Bronze Age civilization that arose on the island of Crete and flourished from approximately the 27th century BC to the 15th century BC. It was rediscovered at the beginning of the 20th century through the work of the British archaeologist Arthur Evans...

 Crete
Crete
Crete is the largest and most populous of the Greek islands, the fifth largest island in the Mediterranean Sea, and one of the thirteen administrative regions of Greece. It forms a significant part of the economy and cultural heritage of Greece while retaining its own local cultural traits...

 at Knossos
Knossos
Knossos , also known as Labyrinth, or Knossos Palace, is the largest Bronze Age archaeological site on Crete and probably the ceremonial and political centre of the Minoan civilization and culture. The palace appears as a maze of workrooms, living spaces, and store rooms close to a central square...

 has a depiction of a fisherman carrying an octopus.

Octopuses were often depicted in the art of the Moche
Moche
'The Moche civilization flourished in northern Peru from about 100 AD to 800 AD, during the Regional Development Epoch. While this issue is the subject of some debate, many scholars contend that the Moche were not politically organized as a monolithic empire or state...

 people of ancient Peru
Peru
Peru , officially the Republic of Peru , is a country in western South America. It is bordered on the north by Ecuador and Colombia, on the east by Brazil, on the southeast by Bolivia, on the south by Chile, and on the west by the Pacific Ocean....

, who worshipped the sea and its animals.

In mythology


The Hawaii
Hawaii
Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...

an creation myth 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.

In literature


The octopus has a significant role in Victor Hugo
Victor Hugo
Victor-Marie Hugo was a Frenchpoet, playwright, novelist, essayist, visual artist, statesman, human rights activist and exponent of the Romantic movement in France....

's book Travailleurs de la mer (Toilers of the Sea
Toilers of the Sea
Toilers of the Sea , is a novel by Victor Hugo.The book is dedicated to the island of Guernsey, where Hugo spent 15 years in exile.The story concerns a Guernseyman named Gilliatt, a social outcast who falls in love with Deruchette, the niece of a local shipowner, Mess Lethierry...

).

As a metaphor


Due to having numerous arms that emanate from a common center, the octopus is often used as a metaphor for a group or organization which is perceived as being powerful, manipulative or bent on domination. Use of this terminology is invariably negative and employed by the opponents of the groups or institutions so described.

As food




Humans eat octopus in many cultures. The arms and sometimes other body parts are prepared in various ways, often varying by species.

Octopus is a common ingredient in Japanese cuisine
Japanese cuisine
Japanese cuisine has developed over the centuries as a result of many political and social changes throughout Japan. The cuisine eventually changed with the advent of the Medieval age which ushered in a shedding of elitism with the age of shogun rule...

, including sushi
Sushi
is a Japanese food consisting of cooked vinegared rice combined with other ingredients . Neta and forms of sushi presentation vary, but the ingredient which all sushi have in common is shari...

, takoyaki
Takoyaki
is a popular ball-shaped Japanese dumpling or more like a savory pancake made of batter and cooked in a special takoyaki pan...

, and Akashiyaki
Akashiyaki
is a small round dumpling from the city of Akashi in Hyōgo Prefecture, Japan. Made of an egg-rich batter and octopus dipped into dashi before eating. Locals refer to it simply as . It is said to start selling modern style akashiyaki in Taishō period by a yatai shopper Seitarō Mukai...

.

In Korea, some small species are sometimes eaten alive
Sannakji
Sannakji or sannakji hoe is a variety of hoe, or raw dish, in Korean cuisine. It consists of live nakji that has been cut into small pieces and served immediately, usually lightly seasoned with sesame and sesame oil. The nakji pieces are usually still squirming on the plate...

 as a novelty food. A live octopus is usually sliced up, and it is eaten while still squirming.



Octopus is eaten regularly in Hawaii
Hawaii
Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...

, since many popular dishes are Asian in origin. Locally known by their Hawaiian or Japanese names ("he'e" and "tako" respectively), octopus is also a popular fish bait.

Octopus is a common food in Mediterranean cuisine and Portuguese cuisine
Portuguese cuisine
Portuguese cuisine is characterised by rich, filling and full-flavored dishes and is closely related to Mediterranean cuisine. The influence of Portugal's former colonial possessions is also notable, especially in the wide variety of spices used. These spices include piri piri and black pepper, as...

. In Galicia, polbo á feira
Polbo á feira
Polbo á feira alternatively known as polbo estilo feira and pulpo á galega is a traditional Galician dish....

 (market fair style octopus) is a local delicacy. Restaurants which specialize or serve this dish are known as pulperías. On the Tunisia
Tunisia
Tunisia , officially the Tunisian RepublicThe long name of Tunisia in other languages used in the country is: , is the northernmost country in Africa. It is a Maghreb country and is bordered by Algeria to the west, Libya to the southeast, and the Mediterranean Sea to the north and east. Its area...

n island of Djerba
Djerba
Djerba , also transliterated as Jerba or Jarbah, is, at 514 km², the largest island of North Africa, located in the Gulf of Gabes, off the coast of Tunisia.-Description:...

, local people catch octopuses by taking advantage of the animals' habit of hiding in safe places during the night. In the evening they put grey ceramic pots on the sea bed. The morning of the following day they check them for octopuses that sheltered there. A common scene in the Greek islands is octopuses hanging in the sunlight from a rope, just like laundry from a clothesline. They are often caught by spear fishing close to the shore. The fisherman brings his prey to land and tenderizes the flesh by pounding the carcass against a stone surface. Thus treated they are hung out to dry, and later will be served grilled either hot, or chilled in a salad. They are considered a superb meze
Meze
Meze or mezze is a selection of small dishes served in the Mediterranean and Middle East as dinner or lunch, with or without drinks. In Levantine cuisines and in the Caucasus region, meze is served at the beginning of all large-scale meals....

, especially alongside ouzo
Ouzo
Ouzo is an anise-flavored aperitif that is widely consumed in Greece and Cyprus, and a symbol of Greek culture.-History:Traditionally, tsipouro is said to have been the pet project of a group of 14th century monks living in a monastery on holy Mount Athos. One version of it is flavored with anise...

.

According to the USDA
United States Department of Agriculture
The United States Department of Agriculture is the United States federal executive department responsible for developing and executing U.S. federal government policy on farming, agriculture, and food...

 Nutrient Database (2007), cooked octopus contains approximately 139 calories per three ounce portion, and is a source of vitamin B3, B12
Vitamin B12
Vitamin B12, vitamin B12 or vitamin B-12, also called cobalamin, is a water-soluble vitamin with a key role in the normal functioning of the brain and nervous system, and for the formation of blood. It is one of the eight B vitamins...

, potassium
Potassium
Potassium is the chemical element with the symbol K and atomic number 19. Elemental potassium is a soft silvery-white alkali metal that oxidizes rapidly in air and is very reactive with water, generating sufficient heat to ignite the hydrogen emitted in the reaction.Potassium and sodium are...

, phosphorus
Phosphorus
Phosphorus is the chemical element that has the symbol P and atomic number 15. A multivalent nonmetal of the nitrogen group, phosphorus as a mineral is almost always present in its maximally oxidized state, as inorganic phosphate rocks...

, and selenium
Selenium
Selenium is a chemical element with atomic number 34, chemical symbol Se, and an atomic mass of 78.96. It is a nonmetal, whose properties are intermediate between those of adjacent chalcogen elements sulfur and tellurium...

.

Care must be taken to boil the octopus properly, to rid it of slime, smell, and residual ink.

As pets


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 its species. By selecting a well-known species, such as the California Two-spot Octopus
California Two-spot Octopus
The California Two-spot Octopus , also known as the "Bimac Octopus", is an octopus species that lives off the coast of California. One can identify the species by the circular blue eyespots on each side of its head. Due to their friendly temperament and relative hardiness, they are considered by...

, one can choose a small octopus (around the size of a tennis ball
Tennis ball
A tennis ball is a ball designed for the sport of tennis,approximately 6.7 cm in diameter. Tennis balls are generally bright green, but in recreational play can be virtually any color. Tennis balls are covered in a fibrous fluffy felt which modifies their aerodynamic properties...

) 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. Large octopuses have also been known to catch and kill some species of shark
Shark
Sharks are a type of fish with a full cartilaginous skeleton and a highly streamlined body. The earliest known sharks date from more than 420 million years ago....

s.

Classification


  • Class Cephalopoda
    • Subclass Nautiloidea: nautilus
    • Subclass Coleoidea
      Coleoidea
      Subclass Coleoidea, or Dibranchiata, is the grouping of cephalopods containing all the primarily soft-bodied creatures. Unlike its sister group Nautiloidea, whose members have a rigid outer shell for protection, the coleoids have at most an internal bone or shell that is used for buoyancy or support...

      • Superorder Decapodiformes
        Decapodiformes
        Decapodiformes is a superorder of Cephalopoda, which includes all species with ten limbs; the name derives from the Greek word meaning ten feet. The ten limbs are divided into 8 short arms and 2 long tentacles. It is presumed that an ancestral coleoid had five identical pairs of limbs, and that one...

        : squid
        Squid
        Squid are cephalopods of the order Teuthida, which comprises around 300 species. Like all other cephalopods, squid have a distinct head, bilateral symmetry, a mantle, and arms. Squid, like cuttlefish, have eight arms arranged in pairs and two, usually longer, tentacles...

        , cuttlefish
        Cuttlefish
        Cuttlefish are marine animals of the order Sepiida. They belong to the class Cephalopoda . Despite their name, cuttlefish are not fish but molluscs....

      • Superorder Octopodiformes
        Octopodiformes
        Octopodiformes is a superorder of the subclass Coleoidea. It comprises the octopuses and the vampire squid. All members of Octopodiformes have 8 arms.-Classification:*Class Cephalopoda**Subclass Nautiloidea: nautilus**Subclass †Ammonoidea: ammonites...

        • Family †Trachyteuthididae (incertae sedis
          Incertae sedis
          , is a term used to define a taxonomic group where its broader relationships are unknown or undefined. Uncertainty at specific taxonomic levels is attributed by , , and similar terms.-Examples:*The fossil plant Paradinandra suecica could not be assigned to any...

          )
        • Order Vampyromorphida
          Vampyromorphida
          Vampyromorphida is an order of cephalopods comprising one known extant species and many extinct taxa. Physically, they somewhat resemble octopuses, but the eight main tentacles are united by a web of skin, and two smaller tentacles are also present.-Classification:*Order Vampyromorphida**?Suborder...

          : Vampire Squid
        • Order Octopoda
          • Genus †Keuppia
            Keuppia
            Keuppia is an extinct genus of octopus. It consists of two species, Keuppia hyperbolaris and Keuppia levante, both of which lived approximately 95 million years ago. Both species were found in fossilized form, which is very uncommon for extinct octopuses, as the soft tissue of dead octopuses almost...

            (incertae sedis
            Incertae sedis
            , is a term used to define a taxonomic group where its broader relationships are unknown or undefined. Uncertainty at specific taxonomic levels is attributed by , , and similar terms.-Examples:*The fossil plant Paradinandra suecica could not be assigned to any...

            )
          • Genus †Palaeoctopus (incertae sedis
            Incertae sedis
            , is a term used to define a taxonomic group where its broader relationships are unknown or undefined. Uncertainty at specific taxonomic levels is attributed by , , and similar terms.-Examples:*The fossil plant Paradinandra suecica could not be assigned to any...

            )
          • Genus †Paleocirroteuthis (incertae sedis
            Incertae sedis
            , is a term used to define a taxonomic group where its broader relationships are unknown or undefined. Uncertainty at specific taxonomic levels is attributed by , , and similar terms.-Examples:*The fossil plant Paradinandra suecica could not be assigned to any...

            )
          • Genus †Pohlsepia (incertae sedis
            Incertae sedis
            , is a term used to define a taxonomic group where its broader relationships are unknown or undefined. Uncertainty at specific taxonomic levels is attributed by , , and similar terms.-Examples:*The fossil plant Paradinandra suecica could not be assigned to any...

            )
          • Genus †Proteroctopus (incertae sedis
            Incertae sedis
            , is a term used to define a taxonomic group where its broader relationships are unknown or undefined. Uncertainty at specific taxonomic levels is attributed by , , and similar terms.-Examples:*The fossil plant Paradinandra suecica could not be assigned to any...

            )
          • Genus †Styletoctopus
            Styletoctopus
            Styletoctopus is an extinct genus of octopus. The genus consists of the single species Styletoctopus annae, which lived approximately 95 million years ago. Very few octopus species appear in the fossil record, as octopuses consist of soft tissue that usually decomposes before it has time to...

            (incertae sedis
            Incertae sedis
            , is a term used to define a taxonomic group where its broader relationships are unknown or undefined. Uncertainty at specific taxonomic levels is attributed by , , and similar terms.-Examples:*The fossil plant Paradinandra suecica could not be assigned to any...

            )
          • Suborder Cirrina: finned deep-sea
            Deep sea
            The deep sea, or deep layer, is the lowest layer in the ocean, existing below the thermocline and above the seabed, at a depth of 1000 fathoms or more. Little or no light penetrates this part of the ocean and most of the organisms that live there rely for subsistence on falling organic matter...

             octopus
            • Family Opisthoteuthidae: umbrella octopus
            • Family Cirroteuthidae
              Cirroteuthidae
              Cirroteuthidae is a family of cirrate octopuses comprising three species in two genera.-Species:*Genus Cirroteuthis**Cirroteuthis muelleri*Genus Cirrothauma**Cirrothauma magna**Cirrothauma murrayi, Blind Cirrate-External links:**...

            • Family Stauroteuthidae
              Stauroteuthis
              Stauroteuthis is a genus of deepwater octopus, a cephalopod mollusk. This is the only genus in the family Stauroteuthidae, and only two species have been described in this genus....

          • Suborder Incirrina
            • Family Amphitretidae
              Amphitretus
              Amphitretus is a genus of pelagic gelatinous octopuses. It is the sole genus of family Amphitretidae and consists of 2 species. Some authorities consider Amphitretus thielei as a subspecies of Amphitretus pelagicus, making this family monotypic.-External links:*...

              : telescope octopus
              Telescope Octopus
              The Telescope Octopus is a species of pelagic octopus found in tropical regions of the Indian and Pacific Oceans. It is transparent, almost colorless and has 8 arms. It is the only octopus to have tubular eyes, hence its common name....

            • Family Bolitaenidae
              Bolitaenidae
              Bolitaenidae is a family of small, common pelagic octopuses found in all tropical and temperate oceans of the world. The family's taxonomy is not entirely certain; recent research suggests there should be just two genera, Bolitaena and Japetella, both of which are thought to be monotypic...

              : gelatinous octopus
            • Family Octopodidae
              Octopodidae
              Octopodidae is the family containing the majority of known octopus species.-Subfamilies and species:*Basal genus Vulcanoctopus*Genus incertae sedis Histoctopus*Subfamily Bathypolypodinae**Genus Bathypolypus**Genus Benthoctopus...

              : benthic octopus
            • Family Vitreledonellidae
              Glass Octopus
              Vitreledonella richardi, also known as the Glass Octopus, is an incirrate octopus. It is the sole representative of the genus Vitreledonella and of the family Vitreledonellidae....

              : Glass Octopus
            • Superfamily Argonautoida
              Argonautoida
              Argonautoida is a superfamily of the suborder Incirrina.-Classification:*CLASS CEPHALOPODA**Subclass Nautiloidea: nautilus**Subclass †Ammonoidea: ammonites**Subclass Coleoidea***Superorder Decapodiformes: squid, cuttlefish***Superorder Octopodiformes...

              • Family Alloposidae
                Seven-arm Octopus
                The Seven-arm Octopus is the largest known species of octopus based on scientific records, with a total estimated length of 4 m and weight of 75 kg...

                : Seven-arm Octopus
              • Family Argonautidae
                Argonautidae
                Argonautidae is a family of cephalopods encompassing the modern paper nautiluses of the genus Argonauta along with several extinct genera of shelled octopods....

                : argonauts
              • Family Ocythoidae
                Tuberculate Pelagic Octopus
                The Tuberculate Pelagic Octopus , also known as the Football Octopus, is a pelagic species that is found in warm and temperate seas, especially in the northern hemisphere. It is the only known species in the family Ocythoidae.The females are around a metre long when full-grown...

                : Tuberculate Pelagic Octopus
              • Family Tremoctopodidae: blanket octopus

See also


  • Octopus wrestling
    Octopus wrestling
    Octopus wrestling involves a diver grappling with a large octopus in shallow water and dragging it to the surface.An early article on octopus wrestling appeared in a 1949 issue of Mechanix Illustrated....

  • Legend of the Octopus
    Legend of the Octopus
    The Legend of the Octopus is a sports tradition during Detroit Red Wings home playoff games where octopuses are thrown onto the ice surface. The origins of the activity go back to the 1952 playoffs, when a National Hockey League team played two best-of-seven series to capture the Stanley Cup...

  • Henry the Hexapus
    Henry the Hexapus
    Henry the Hexapus was a six-limbed octopus found by British marine scientists in 2008. The name alludes to King Henry VIII, who had six wives....

    , a six-armed octopus
  • Paul the Octopus
    Paul the Octopus
    Paul the Octopus was a common octopus from Weymouth, England. Paul lived in a tank at a commercial attraction, the Sea Life Centre in Oberhausen, Germany and became internationally famous after his feeding behaviour was used to correctly predict the winner of each of the Germany national football...

    , an octopus famous for predicting football results in the 2010 FIFA World Cup
    2010 FIFA World Cup
    The 2010 FIFA World Cup was the 19th FIFA World Cup, the world championship for men's national association football teams. It took place in South Africa from 11 June to 11 July 2010...



External links