An octopus is a soft-bodied, eight-limbed mollusc of the order Octopoda. The order consists of some 300 species and is grouped within the class Cephalopoda with squids, cuttlefish, and nautiloids. Like other cephalopods, an octopus is bilaterally symmetric with two eyes and a beaked mouth at the centre point of the eight limbs. The soft body can radically alter its shape, enabling octopuses to squeeze through small gaps. They trail their eight appendages behind them as they swim. The siphon is used both for respiration and for locomotion, by expelling a jet of water. Octopuses have a complex nervous system and excellent sight, and are among the most intelligent and behaviourally diverse of all invertebrates.
Opisthoteuthis californiana, also known as the flapjack octopus, or flapjack devilfish is a species of umbrella octopus.
The California two-spot octopus, often simply called a "bimac", is an octopus species native to many parts of the Pacific Ocean including the coast of California. One can identify the species by the circular blue eyespots on each side of its head. Bimacs usually live to be about two years old. They are closely related to Verrill's two-spot octopus. In 2015, the genome was sequenced.
The southern blue-ringed octopus is one of three highly venomous species of blue-ringed octopuses. It is most commonly found in tidal rock pools along the south coast of Australia. As an adult, it can grow up to 20 centimetres (8 in) long and on average weighs 26 grams (0.9 oz). They are normally a docile species, but they are highly venomous, possessing venom capable of killing humans. Their blue rings appear with greater intensity when they become aggravated or threatened.
The greater blue-ringed octopus is one of four species of extremely venomous blue-ringed octopuses belonging to the family Octopodidae. This particular species of blue-ringed octopus is known as one of the most toxic marine animals in the world.
The Atlantic pygmy octopus, also known as the small-egg Caribbean pygmy octopus, is a small species of octopus in the order Octopoda. Fully grown, this cephalopod reaches a mantle length of 4.5 cm with arms up to 9 cm long. They are known for being intelligent creatures with keen senses, particularly good sight.
Octopus rubescens is the most commonly occurring shallow-water octopus on much of the North American West Coast and a ubiquitous benthic predator in these habitats. Its range extends from the southern Gulf of California to at least the Gulf of Alaska, but may also occur in the western Pacific Ocean. O. rubescens occurs intertidally to a depth of 300 m (980 ft).
Octopus cyanea, also known as the big blue octopus or day octopus, is an octopus in the family Octopodidae. It occurs in both the Pacific and Indian Oceans, from Hawaii to the eastern coast of Africa. O. cyanea grows to 16 cm in mantle length with arms to at least 80 cm. This octopus was described initially by the British zoologist John Edward Gray in 1849; the type specimen was collected off Australia and is at the Natural History Museum in London.
The Caribbean reef octopus is a coral reef marine animal. It has eight long arms that vary in length and diameter. In comparison to the arms, the mantle is large and bulky. This species is difficult to describe because it changes color and texture to blend into its surroundings, using specialised skin cells known as chromatophores. Its color range is very large; it can change from crimson to green, and bumpy to smooth. It weighs around 3.3 lb or 1.5 kg.
Macroctopus maorum is known more commonly as the Maori octopus or the New Zealand octopus. It is found in the waters around New Zealand and southern Australia. M. maorum is one of the largest and most aggressive octopus species living in the New Zealand and Australian waters. They feed mainly on crustaceans and fish. Although they have a short life span, the females lay thousands of eggs and are very protective of them.
Octopus aquaculture describes the captive-raising of octopuses and commercial sale of their meat. A complex and labor-intensive form of farming, octopus aquaculture is being driven by strong market demand in the Mediterranean and in South American and Asian countries. Annual global demand for octopus more than doubled from 1980 to 2019, from roughly 180,000 to about 370,000 tons. The supply of octopus has been constrained by overfishing in many key fisheries and proponents of farming suggest human-induced culturing could help restock natural populations. Opponents of the nascent industry argue that cephalopod intelligence and emotional capacity, as well as the solitary and carnivorous character of octopuses, make them particularly ill-suited to intensive, captive breeding. Commercial sale may stimulate market demand, hastening rather than offsetting the decline in wild stocks. An announcement that a Spanish firm would begin octopus aquaculture as early as 2022 prompted ethical and scientific controversy.
Octopus tetricus, the gloomy octopus or the common Sydney octopus, is a species of octopus from the subtropical waters of eastern Australia and New Zealand. O.tetricus belongs to the Octopus vulgaris species group and is a commercially prized species. All species within the O. vulgaris group are similar in morphology. The English translation of O. tetricus (Latin) is 'the gloomy octopus'.
Pinnoctopus cordiformis is a species of octopus found around the coasts of New Zealand. It is one of the most common species of octopus in the country.
The larger Pacific striped octopus (LPSO), or Harlequin octopus, is a species of octopus known for its intelligence and gregarious nature. The species was first documented in the 1970s and, being fairly new to scientific observation, has yet to be scientifically described. Because of this, LPSO has no official scientific name. Unlike other octopus species which are normally solitary, the LPSO has been reported as forming groups of up to 40 individuals. While most octopuses are cannibalistic and have to exercise extreme caution while mating, these octopuses mate with their ventral sides touching, pressing their beaks and suckers together in an intimate embrace. The LPSO has presented many behaviors that differ from most species of octopus, including intimate mating behaviors, formation of social communities, unusual hunting behavior, and the ability to reproduce multiple times throughout their life. The LPSO has been found to favor the tropical waters of the Eastern Pacific.
Octopus bimaculatus, commonly referred to as Verrill's two-spot octopus, is a similar species to the Octopus bimaculoides, a species it is often mistaken for. The two can be distinguished by the difference in the blue and black chain-like pattern of the ocelli. O. bimaculatus hunt and feed on a diverse number of benthic organisms that also reside off the coast of Southern California. Once the octopus reaches sexual maturity, it shortly dies after mating, which is approximately 12–18 months after hatching. Embryonic development tends to be rapid due to this short lifespan of these organisms.
Octopus insularis is a species of octopus described in 2008 from individuals found off the coast of Brazil, with a potentially much larger range.
Opisthoteuthis agassizii is a lesser-known, deep-sea octopus first described in 1883 by Addison E. Verrill.
Bathypolypus sponsalis, commonly called the globose octopus, is a deep sea cephalopod that can be found in both the eastern Atlantic Ocean and the Mediterranean Sea. It possesses many morphological traits adapted to a deep sea environment, including large eggs, reduced gills, no ink sac, and subgelatinous tissues. A distinguishing factor are the relatively large reproductive organs. Their diet consists of predominantly crustaceans and molluscs, but they sometimes consume fish as well. Bathypolypus sponsalis usually dies quickly after reproduction and only spawns once in their lifetime. Sexually mature females have a mantle length of at least 34 mm and sexually mature males have a mantle length of about 24 mm. Juveniles are white and transition to dark brown then to dark purple once maturity is reached.
Octopus sinensis is a mollusk belonging to the class Cephalopoda. Octopus sinensis is a well-known shallow-water benthic octopus species found in the coastal, temperature waters of South Korea, China, and Japan, with the species name, sinensis being Latin for Chinese. Octopus sinensis is closely related to the Atlantic and Mediterranean common octopus, Octopus vulgaris. Because of the morphological similarities, O. sinensis was considered synonymous with Octopus vulgaris until 2017. Octopus sinensis are carnivores that prey upon on many shallow-water animals such as crustaceans and mollusks.
Octopus hubbsorum, is an octopus in the family Octopodidae. It is commonly found along tropical waters along the central Pacific Coast of Mexico. Here, they are one of the most commonly caught cephalopods and are commercially extremely important for the economy.
