squid (Teuthida) is his vulgar name, his real name is teutido belonging to the order of the cephalopod molluscs. This order contains two orders known as Myopsin and Oegopsin.

In the seas of the entire planet there are approximately 300 species of squid, being one of the few animals that is capable of living in the extreme waters of Antarctica.

Squid seen from the side

Squid seen from the side

Features

The squid is a cephalopod similar to the octopus. Like most cephalopods, the squid has a distinct head, mantle, and arms. It is also bilaterally symmetric. Like the cuttlefish, it has two arms and two tentacles arranged in pairs. There are some species known to have 10 arms. In the mature male, a basal half of the left ventral tentacle is hectocotylized and instead of suction cups it has a copulatory pad used for sexual intercourse.

The vast majority of species are about 20 cm long when fully stretched, although other species can reach 60 cm. The colossal squid from the deep waters of the Pacific Ocean is known to be about 14 meters in length.

They have three hearts. Two of them are known as branchial hearts that feed the gills and surround the third heart, the systemic heart that is the largest that sends blood throughout the body. Blood contains the protein hemocyanin to carry oxygen. The systemic heart is made up of three chambers, a lower ventricle and two upper atria.

The mouth features a robust, horny beak affiliate made of chitin and cross-linked proteins, containing no minerals, used to kill and tear prey. Sometimes some whales have indigestible squid beaks in their stomachs. In the mouth we can find the radula, the rough tongue common in all mollusks with the exception of the bibalvia.

The eyes are positioned on both sides of the head, each containing a hard slow. The image is focused like a camera or telescope, rather than changing the shape of the target like the human eye. Squid hearing is quite limited.

The main body mass is enclosed in the mantle that has a swimming fin on each side but they are not the main form of locomotion. The skin is composed of chromatophores that allow it to camouflage itself in its environment by being able to change color.

Below the body are openings to the hollow mantle that contains the gills, excretory and reproductive systems. At the front is the siphon that is used to propel itself with a precise jet. To achieve this, it sucks the water into the mantle and is expelled through the siphon. The direction of the siphon can be adapted to the direction of travel.

Next to the excretory system is the ink sac that allows it to quickly shoot black ink into the hollow of the mantle and then be expelled through the siphon. It is used to mislead the predators after the flight.

Within the hollow mantle, further from the siphon, we can locate the visceral mass covered by a thin and membranous epidermis that protects the main internal organs.

Among the qualities of squid, their intelligence stands out, which is quite high compared to other invertebrates. Some species like the Humboldt squid hunt cooperatively, using active communication. They are also great swimmers and some species can "fly" short distances above the sea surface.

In general, it only lives for a few years in the wild before being eaten. However, some of the larger species can reach 15 years of age.

Habitat

The squid's habitat depends on the species. Some thrive in warm waters in the tropics and others do much better in cooler waters. There are squids in every ocean, however, giant squids are only found in saltwater oceans. They also prefer the depths of the ocean (about 300 meters) where they go unnoticed most of the time.

The ocean with the most varieties of species is the North Atlantic Ocean but they can also be found in large numbers around the Gulf of Mexico, Hawaii, and California. It has also been seen in the North Pacific starting in the Bering Sea to the Sea of ​​Japan. Squid have also been found in regions of the Southern Ocean.

Caribbean squid in clear water

Caribbean squid in clear water

Food

The squid is a carnivorous animal and mainly feeds on Kirll and Plankton, although larger species of squid feed on larger pieces such as fish, crabs, and shrimp. If food sources are scarce, they will feed on other smaller squid species.

Predators

Squids have numerous predators and are food sources for fish, sharks and sperm whales (when talking about the giant squid). Their eggs are also consumed when they are deposited in water. On land they also have predators such as birds, penguins, seals and humans.

Reproduction

Squid have an interesting way of reproducing. When it is time to mate they concentrate in large schools, both male and female, swimming rapidly in large circles. Males change color to attract females to them and once the female has shown interest, mating begins.

Females have an ink sac hidden under a set of glands in their gills that serves as a protective shell for the eggs. The male has a tentacle smaller than the rest (the equivalent of the human penis) that he will introduce into the female's ink sac where he will release sperm so that they fertilize the eggs.

It is unknown how the eggs develop inside the female, but the eggs are very small although they depend on the species. The number depends on the species and some lay up to 70.000 eggs, however, the vast majority are eaten by predators.

Finally, the female will leave them hidden between rock crevices or in various holes. It can take about eight weeks for the eggs to hatch and they do not wait for them to hatch, as soon as they are deposited they will go away. So the squid must manage from the beginning and they are already prepared from day one because they already know how to swim, although most will die in their first days of life.

State of conservation

Among the various species of squid, none are in danger of extinction. Although its short life span is cause for concern, mainly due to the overwhelming demand from humans.

Squids are also a species affected by climate change and global warming.

Popular culture

Urban legend

Creak, a giant squid, is perhaps the largest monster ever imagined by mankind. In Norse folklore, it was said that he frequented the seas from Norway to Greenland, passing through Iceland.

The Kraken had a knack for harassing ships and many pseudoscientific reports (including naval officers) said it would attack ships with its strong arms. If this strategy failed, the beast began to circle the ship, creating a ferocious maelstrom to drag the ship down.

Legends say that the Kraken could devour the entire crew of a ship at once.

The kraken is a gigate squid surrounded by many urban legends.

The kraken is a gigate squid surrounded by many urban legends.

TV

Without a doubt, the most famous squid is Squidward Tentacles (Squidward Q. Tentacles) Of sponge Bob (SpongeBob SquarePants), a Nickelodeon series released on July 17, 1999.

The neighbor and co-worker of SpongeBob, employee of the Mister crab, is defined by his sharp demeanor and pessimistic attitude in contrast to SpongeBob. SpongeBob's best friend is a starfish named Patrick.

Squidward, from the animated series SpongeBob SquarePants.

Squidward, from the animated series SpongeBob SquarePants.

List of other interesting animals