What is the difference between an octopus and a squid?

One of the most frequently asked questions is to know the differences between two animals that visually present certain similarities, but that undoubtedly have their specific characteristics.

The octopus and the squid belong to the group of cephalopods, marine mollusks generally without shell or external valva, which have a bulky head and a series of tentacles around the mouth.

The squid is also called cuttlefish or squid. It is a cephalopod mollusk, decapod. It lives near the coast, at depths of 15 to 600 meters, preferring open waters as it is a permanently mobile animal. They live between 2 and 5 years.

The squid is a pelagic and gregarious animal, forming numerous schools that travel long distances and make frequent vertical movements, sometimes to great depths.

Its diet consists of fish, crustaceans and other invertebrates, including other cephalopods. To feed, it throws its two major tentacles at its prey and then grasps them firmly with the other eight arms.

The etymology of the word comes from the Latin calamarius (containing reeds for writing) from calamos (reed or writing pen). In French it meant "portable desk" until the 18th century.

Some particularities of the squid are:

• Cephalopod mollusks possess pigment cells called chromatophores, which allow them to change their external color. They use them to communicate with each other and also allow them to change color when they feel threatened, a strategy that they combine with the expulsion of the ink they produce.

• They have a muscular and flexible body (octopuses can hide in spaces 10 times smaller than their body).

• The ink is a pigment that is stored above the rectum and can be expelled through the siphon. Recent research has discovered that the ink of cephalopods, in addition to serving as a condiment in different recipes, contains a series of amino acids and polysaccharides that are very effective in preventing and curing some diseases. It has been found that these substances can act as active ingredients in the treatment of depression. It has also been shown that octopus and squid ink inhibits bacterial growth due to the presence of a certain protein in its composition. Finally, a study carried out by Japanese scientists on the ink of several species of cephalopods has produced preliminary results indicating the antitumor activity of certain chemical substances present therein.

• In December 2006, a Japanese ship caught a 7.2 m giant squid.

The octopus, a cephalopod invertebrate, has 8 tentacles around its mouth, and on each tentacle there are two rows of suckers that help it to catch its prey. Octopuses have the ability to adapt their color and body surface to the characteristics of the environment. The octopus' body also helps it recognize its "mood", so it is blue when it is nervous, pale when it is afraid, or reddish when it is angry. They can weigh up to 10 kg and their arms can be up to 1 m long.

They are nocturnal animals; during the day they hide. They move very easily through the water with the help of the siphon, a funnel in the respiratory cavity through which they expel water, and their arms allow them to crawl or move on rocky bottoms. To defend themselves, they can also expel ink, like most cephalopods.

They feed on crustaceans, other mollusks and fish, therefore, they are carnivorous.

Octopuses are oviparous. Octopuses copulate, after making a nuptial stop. One of the male's tentacles has reproductive functions and is detached and remains inside the female. Laying takes place during spring and summer. The female stops eating after laying and takes care of them, but dies soon after. The male returns to the depths.

One of the peculiarities of octopuses, it is an animal that changes color faster and also possesses an intelligence similar to that of a puppy dog since it has a real brain and its eyes are able to distinguish shapes and colors.

These mollusks certainly look alike, but they are not the same, let's see the differences:

• Octopuses are octopodids (eight tentacles) and decapod squids (8 arms and two tentacles).

• Squids have a long, conical body and a fin on each side of their body. Octopuses have a large head and an oval body. The body does not have an internal shell and fins are absent.

• The average lifespan of octopuses ranges from 1 to 3 years, while squids range from 9 months to 5 years.

• The size of octopuses ranges from 1 centimeter to 5 meters long and squids from 1 centimeter to 20 meters long.

• Squids prefer to live in the open sea and at a maximum depth of 1,000 meters, while octopuses prefer sea caves and burrows, among coral reefs, under rocks or near the surface.

• Despite their differences, both species share something in common: they are delicious and nutritious foods. Their health benefits are very similar, although their taste and texture are very particular. For this reason, octopus and squid are highly valued in many kitchens, as they are used to prepare delicious recipes.

In short, both animals have characteristic features that make them incredible and super delicious species.