octopus

octopus

Octopus: a general term for 252 species of marine mollusks belonging to 26 genera of Octopus family. It is the largest family of Cephalopoda and can be divided into bathypolypodinae, eledoninae, graneledoninae and octopodinae. The body is ovoid or ovoid with strong muscles, narrow opening of mantle cavity and no water hole on the body surface. Wrist sucker 1 or 2 rows. In males, the third wrist on the left or right is stemmed, with a seminal groove at the ventral margin of the wrist and a spoon shaped tongue at the end. The funnel lock degenerated. Endocarp degenerate or without inner shell. If there is a lingua, the lingual side teeth are generally single pointed. The stomach and cecum are located at the back of the digestive gland.

This family is one of the most important commercial cephalopods in China. Both Octopus (Octopus vulgaris) from the southern coast and Octopus ocellatus from the northern coast have a certain yield. The dried octopus is called "octopus dried" or "octopus dried". In addition to edible, it also has the function of tonifying blood and Qi, astringency and muscle growth in medicine.

As a temperate mollusk, it lives under water and can not adapt to the water temperature lower than 7 ℃. The seawater specific gravity of 1.021 is the most suitable. It will die in low salinity environment. It can feed on macrozooplankton and grow. It is widely distributed in tropical and temperate waters of the world's oceans.

morphological character

There are more than 252 species of marine mollusks belonging to 26 genera in the octopus family, and their sizes vary greatly. The body of octopus is short ovoid, saccate, without fins; the division between head and body is not obvious; the head and carcass of octopus is about 7-9.5 cm, with large compound eyes and 8 retractable wrists. Each wrist has two rows of fleshy sucker. The length of the wrist of Octopus ocellatus is about 12 cm, that of Octopus ocellatus is about 48.5 cm, and that of Octopus ocellatus is about 32.5 cm. Usually crawls with the wrist, sometimes swims by stretching the intercarpal membrane, can hold other things forcefully, and uses the funnel at the lower part of the head to spray water for fast swimming. The base of the wrist is connected to webbed tissue called the skirt, with a mouth in the center. The mouth has a pair of sharp horny palate and rasp like teeth tongue, which are used to drill the shell and scrape its meat.

The most well-known octopus in this family is o. vulgaris. It is of medium size and widely distributed in tropical and temperate waters all over the world. It lives in caves or crevices on rocky seafloor and likes to hide. This species is considered to be the most intelligent of invertebrates. It has highly developed pigmented cells and can change body color very quickly. The smallest octopus is the Atlantic dwarf Octopus (Octopus joubini), about 14 cm long; the Atlantic dwarf octopus is very strong, with a sucker with a diameter of about 2.5 mm on its wrist and hand that can hold 48 grams of objects. The largest octopus is the giant octopus (enteropus dofleini) in the North Pacific. In February 1973, a diver caught a giant octopus in the shahood canal in Washington, D.C. with its wrist and foot outspread, the octopus has a diameter of 15.6 meters and weighs 53.6 kg. Octopus 1.5-2 meters long, suction cup diameter of about 6 mm, suction for more than 100 grams. They are often able to haul large stones 5, 10, or even 20 times their own weight.

The octopus can not only spray ink six times in a row, but also change its color and structure like the most flexible chameleon, becoming like a stone covered with algae, and then suddenly pounce on its prey, who has no time to realize what happened. Octopus can use their flexible wrists and feet to crawl between reefs, crevices and seabed, sometimes disguised as a bunch of coral, sometimes disguised as a pile of shining gravel. Mark Norman of the University of Melbourne, Australia, discovered an octopus in the estuarine waters near Sulawesi island, Indonesia, in 1998, which can quickly mimic poisonous creatures such as sea snakes, lionfish and jellyfish to avoid attack.

Habitat

Octopus is a temperate mollusk. It lives under water. The water temperature should not be lower than 7 ℃, and the proportion of seawater is 1.021. It will die in low salinity environment. The best bottom material in the sea area is gravel zone. When the water temperature is above 12 ℃, the larvae can lay eggs every year. After hatching, the total length of the larvae is about 3 mm, and they can feed on macrozooplankton and grow up. After 45 days, when the total length reaches 10-13 mm, they will settle in the benthic life of the submarine camp. If there is no ceramic tile can conch shell for living room, they will build houses by themselves.

Life habit

food

Carnivorous, to Lamellibranchia and crustaceans (shrimp, crab, etc.) for food, some species of plankton. It's not a matter of whether it likes it or not, because stable structural myoglobin is a necessary condition for octopus to survive in the deep sea. It's fighting with lobster to fight for astaxanthin (ASTA) resources. Astaxanthin is the strongest antioxidant, which is a necessary condition to ensure the structural stability of myoglobin without being oxidized. In 2008, according to Professor Francesco Buda, a scientist at Leiden University in the Netherlands, and members of his experimental team, through accurate quantum calculation, it was found that the representative fish of cooked shrimp, crab and salmon showed attractive bright red, because shrimp, crab and salmon were rich in astaxanthin, and the representative fish of cooked shrimp, crab and salmon were rich in astaxanthin Astaxanthin is a kind of natural red substance.

behavior

The octopus sucks water into the mantle, and after breathing, the water is discharged through the short funnel-shaped body tube. Most Octopus crawl along the bottom of the sea with suction cups, but when they are frightened, they will spray water from the body tube, which is strong enough to move quickly in the opposite direction. In case of danger, ink like substances will be ejected as smoke screens. Some species produce substances that paralyze the attacker's sense organs.

In order to avoid the predator's killing, in addition to using the well-known mimicry camouflage technique and abandoning the wrist technique, American scientists have also found "high intelligence" octopus that can escape by walking on two feet in the Indian Ocean. Christine heffard of the University of California at Berkeley and his team photographed an octopus named majinetes in the tropical waters of Indonesia, about the size of an apple. In the face of danger or divers, the octopus would bend six of its eight "claws" upward to make a coconut shell, while the remaining two "claws" would stand on the ground On the bottom of the sea, he secretly moves backward, like a small coconut that can move. He escapes by stepping backward. His posture is very funny.

There's another walnut sized aculitus octopus that also walks on two feet, but the other six legs stretch out, mimicking the appearance of seaweed. The team found that walking with two brachiopods is much faster than walking with eight brachiopods, with the fastest speed of about 0.14 meters per second.

hobby

Octopus is fond of all kinds of utensils, eager to hide in hollow utensils. Octopus not only love to drill bottles and jars, all containers, it likes to drill in to live. A 9-liter bottle with a diameter of less than 5 cm was fished out in the English channel, and an octopus with a body thickness of more than 30 cm was found inside. In the cargo hold of an ancient Greek shipwreck not far from Marseilles, France, it was filled with two ear bottles and large water tanks for noodles. Almost every one contained an octopus. The collapse of the three story ship provided thousands of good homes for the octopus. For more than 2000 years, octopus have lived in such wrecks for generations. After the plane sank to the bottom of the sea, the gasoline tank also provided a shelter for the clever octopus. Even the skulls of people fished out of the Mediterranean contain an octopus.

In view of octopus's hobby of drilling utensils, people often use earthen pots, bottles and fishing gear to catch octopus. Every morning, Japanese fishermen tie pottery pots of various shapes to long ropes and sink to the bottom of the sea. After a period of time, the fishermen put up the pottery pot. At this time, as long as they sprinkle a little salt into the pot, the octopus who stubbornly refuses to come out of the pot will come out. Indian fishermen use conch shells in the same way. They often weave eight or nine hundred shells of the sea snail into a net to catch two or three hundred octopus a day. Cuban fishermen use the shell to trap octopus. Tunisian fishermen can also catch Octopus by throwing drains to the bottom of the sea.

Mimicry

On the surface of octopus, there is a kind of cell called chromatophores. Each pigment cell contains one of four natural pigments: yellow, red, brown or melanin. These pigments can only be seen when the pigment cells contract. Octopus can change its color by contracting only one pigment cell at a time. It can also evade predators by camouflage and capture prey by showing the same color as clear water, sandy seabed or black crevices. When an enemy approaches, the octopus turns dark pink, releases a mass of black ink from the ink bag, called sepia, and then fades away.

thinking

Jim Cosgrove, an expert who has been engaged in Octopus research for many years, pointed out that octopus has "conceptual thinking" and can solve complex problems by itself. It is this ability that makes Octopus have the ability to walk with two feet. Jim Cosgrove wrote in the French magazine Figaro that octopus is one of the most different creatures on earth. Octopus has developed eyes, which is the only similarity between octopus and human. It's very different from humans in other ways: octopus has three hearts and two memory systems (one is brain memory)

Chinese PinYin : Zhang Yu