Characteristics and anatomy of the octopus: is the octopus a mollusk?
The octopus is a mollusk belonging to the class of cephalopods and has extremely ancient origins: the most historic fossil dates back to 296 million years and is located at the Field Museum in Chicago. There are more than 300 species of octopus, and despite varying in size and some aesthetic details, they all have the same anatomy. The most common and widespread in Italian waters is the Octopus Vulgaris. It reaches 150 cm in length and the most developed species can weigh over ten kilograms. From an anatomical point of view, the octopus is characterized by the absence of an exoskeleton, which allows it to nest comfortably in the narrowest ravines. It has a globular head with two eyes that, thanks to the position of the retina, have a complete vision without suffering from the so-called blind spot. In the head pouch are found most of the octopus' vital organs, including the three hearts that regulate the octopus' vital flow: two are needed to pump venous blood into the gills, the other regulates the remaining organs. The color of the octopus' blood is blue: in fact, it contains enocyanin, a protein containing copper, that converts to a blue color when in contact with oxygen.
More than 300 species of octopus exist, varying in size and color. The class to which octopuses belong, namely cephalopods, includes five macro categories: octopus, the musky octopus, cuttlefish, European flying squid, European squid. But how to tell the difference between an octopus and a musky octopus? What is the difference between octopus and white spotted octopus or what is the difference between polpo (octopus) and piovra (giant octopus)? Let's see it together
How to distinguish the octopus from a musky octopus?
Generally, but not always, musky octopuses are smaller than octopuses. In fact, they turn out to be very similar, as they have 8 arms (not a coincidence that they belong to the order of Octopoda, "eight feet") of equal size, but octopuses have two rows of suckers along each arm, unlike the musky octopus, which has only one. Here is the first curiosity about octopuses, a false myth: octopuses do not have tentacles, but arms equipped with rows of suckers, whereas cuttlefish and squid have 8 arms and 2 tentacles.
What is the difference between ‘polpo’ (octopus) and ‘piovra’ (giant octopus)?
The word "piovra" has often been used to refer to the female octopus, but this is a mistake: the ‘piovra’ simply does not exist. Taking up the definition of “piovra” (giant octopus) from the Treccani encyclopedia, the word “piovra” (giant octopus) is used to "indicate some of cephalopod mollusks living in the great marine depths, believed to be of gigantic shapes", confirming that we commonly call particularly big octopuses ‘piovra’," although not having certainty of their real existence. The term ‘piovra’ is believed to derive from the French word ‘pieuvre’ meaning precisely "octopus."
Differences between polpo (common octopus) and polpessa (white spotted octopus)
Polpo (common octopus) and ‘polpessa’ (white spotted octopus) are two distinct, although similar species of octopus. They differ in color (the octopus is dark in color, between brown and reddish, while the white spotted octopus tends to be brick-red with irregular white spots), for the weight (the octopus can reach up to 10 kg while the white spotted octopus reaches a maximum of 2 kg), and for the habitat (the octopus prefers rocky substrates while the white spotted octopus moves to sandy bottoms).
Is it called polipo or polpo?
In Italian, the ‘polpo’ (octopus) is exclusively called ‘polpo’ (octopus). The term ‘polipo’ is wrong and it is not only a grammar mistake: the ‘polpo’ (octopus) are aquatic animals belonging to the class of sea anemones and represent one of the pre-evolutionary life stages of jellyfish. Furthermore, the term ‘polipo’ (polyp), in general medicine, refers to an abnormal growth of tissue that stands out from a mucous membrane.
How many tentacles does an octopus have and what are they for?
The octopus has eight tentacles (which are technically arms, because as explained earlier octopuses do not have tentacles) and in the center of them you find the mouth, which is characterized by a pointed beak - similar to that of parrots - that can be used both as defense and to prey. The octopus uses its tentacles to move by crawling on surfaces, whether it is the seabed or reef, and only occasionally uses the pressure of the siphon, an organ used to expel water that produces a locomotive force. The octopus' tentacles are useful for the mollusk to catch food and carry it to its mouth, as well as to hunt. Half a billion neurons are distributed in the octopus' tentacles, which have their own autonomy of movement: when needed, in the event that a predator forces it to flee, the octopus can detach a tentacle from itself as a distraction and escape.
Why is the octopus intelligent?
The octopus is considered the most intelligent animal, it has about five hundred million neurons, two hundred million of which are located in the brain and the other three in the arms. As demonstrated by the Okinawa Institute of Science and Technology Graduate University, the octopus has only one brain. The intelligence of the octopus is very sophisticated and enshrines its behavioral habits. The octopus is believed to be an intelligent animal because it can solve small tasks such as opening a jar containing food, it can use any objects to build a temporary lair for itself (coconuts, giant shells), and sabotage the security systems of aquariums that keep it in captivity, even being able to find its way around in a maze. The octopus is able to camouflage itself with precision: it chooses an element of the seabed and camouflages itself as such, even managing to change the texture of its skin to get as close as possible to the camouflage target, recreating, for example, the ripples of a seaweed. To disorient predators, it uses a jet of ink, which, in addition to facilitating their escape behind the black blanket, physically harms the enemy itself, as it contains an enzyme called tyrosinase that irritates the eyes and reduces the sense of smell.
How do octopus reproduce?
How are octopus born and how does their reproduction work? The male octopus courts the female and then inserts the hectocotylus, one of eight "tentacles," inside the female's siphon to reach the sac (called the ball cavity) and releases the spermatophores near the ovaries. At the end of the intercourse, the male octopus may detach the hectocotylus to get away: at the end of the intercourse, it is not uncommon for the male octopus to be cannibalized by his mate, so "losing" a tentacle helps the male save himself. After 30 to 40 days of gestation, the female locates a safe shelter and lays the tiny eggs, which she hangs on the rocky walls of a rocky crevice. The eggs average from 50,000 to 400,000, and the mother will not stop watching over them even for a minute, even giving up feeding itself in order to protect its offspring.
What do octopus feed on?
The octopus' diet consists mainly of bivalve mollusks such as mussels, clams, oysters and also gastropods and small fish. It uses its sharp beak to pierce the shells and get at the vital flesh of the seafood. The octopus’ predators are generally groupers, moray eels, conger eels and also sharks.
How to catch the octopus?
Octopus fishing is an activity carried on for centuries in coastal towns by commercial fishermen and also by amateurs, as octopus can be caught by scuba diving, by boat or directly from the shore. There are many techniques to catch octopus:
- With the polpara technique (a special fishing tool): a bait full of hooks, often shaped like a crab and with a white cloth attached to it to "intrigue" the octopus.
- Fishing with the eging technique: that is using a bait that resembles the shape and color of shrimps.
- Bolognese fishing technique: standard fishing rod technique, with a float, lead shots and a couple of hooks.
- In freediving with a spear: when diving, the diver must be skilled to recognize the camouflaged octopus to be able to catch it with a spear.
- Gillnetting technique: known also as trammel net, this technique is mainly used by professional fishermen.
Octopus in cuisine: how to clean freshly bought octopus
Should your octopus fishing be successful, you will need to follow a series of important steps to have a perfect final product. The rite of "slammed and curled" octopus is typical in some parts of southern Italy, but if you have bought it fresh and don't know how to clean the octopus at home before cooking it, here are our tips. To clean the octopus, follow these steps:
- Take out the eyes and beak with the blade of a knife.
- Turn the head pouch inside out, remove the organs and rinse the octopus repeatedly till it is completely clean, without any residues.
- To make a fresh un-slammed and un-curled octopus soft, simply freeze it. The cold and below-zero temperature will tenderize the octopus meat, breaking the rigid fibers of the tentacles. To have the certainty of a soft octopus, keep it in the freezer for at least 48 hours.
Octopus’ Nutritional values
The octopus nutritional properties are so low in fat and have a high satiating power, making it an ideal food for low-calorie diets. It provides less proteins than other types of fish, but it compensates with the presence of minerals and vitamins, such as calcium, magnesium, phosphorus, potassium, sodium, selenium, vitamin C, vitamin B12 and vitamin A.
100 gr of octopus correspond to 57 kcal, distributed over the main macronutrients as follows:
- Protein: 10.6 g
- 1 g fat
- 1.4 g of carbohydrates
- 57 Kcal
How to cook the octopus
Cooking octopus is simple with our tips: you can use it in all your recipes and cook it in multiple ways. Here we will show you how to prepare boiled, steamed, grilled, fried octopus or simply how to cook octopus without water.
Boiling the octopus is the most common and versatile method for cooking it: the octopus is immersed in a deep and large pot, filled with cold water along with a few laurel leaves, pieces of lemon and celery. The water should come to a boil, then be turned off and the octopus left to rest in the pot. The proper procedure involves first soaking only the tentacles in a pot of boiling water, which should be soaked repeatedly to be properly curled.
This is a very gentle way to cook the octopus, as the heat of the steam will prevent the skin from breaking and give back full tenderness. Simply use a steam cooker and cook by steaming the octopus.
Some people boil the octopus before grilling and some people place it directly on the barbecue when raw. Our advice is to boil the octopus beforehand, and then grill it if you do not have a professional barbecue and if you do not have a well-curled fresh octopus.
After a partial boiling, the octopus is then fried - with or without breadcrumbs depending on the tradition and the recipe - in a deep frying pan with plenty of hot oil at a temperature of 180 degrees.
Octopus cooked without water, au naturel
An extremely natural cooking technique, that of the "octopus all'acqua sua (octopus in its own water)". The octopus is cooked in a large pot without the addition of liquid on low heat along with a sauté of cherry tomatoes, onion and parsley and will release "its water" directly into the pot.
How to cook frozen octopus?
Frozen octopus can be cooked directly in the pot, without defrosting. To soften frozen octopus and prevent it from hardening, the care to follow is to soak the octopus in a pot with cold water to avoid a heat shock that could harden the tentacles meat. In this way, the water will gradually come to a boil and you can follow the cooking time according to the size of the octopus and the use you will make of it in cooking.
Octopus cooking time: how to tell if the octopus is cooked?
Octopus cooking time varies depending on the weight of the species itself. Taking boiling as the key cooking technique, it generally takes at least forty minutes on low heat to cook a pound of soft octopus and twenty minutes of resting time with the heat off. To understand if the octopus is cooked there is the fork test: if the tines of the fork easily go through the head of the octopus (which should be soft), then the cooking of the octopus is complete and you can let the octopus rest in a bowl, without water, so that it cools little by little and the meat remains tender and soft.
The octopus is very versatile in cooking: you can use it to make a seafood appetizer or as a ragu (sauce) for a spaghetti dish, or also to make an octopus burger (by the way, check out this recipe with octopus burger paired with carbonara sauce, lettuce, capocollo salami, sauteéd zucchini with almonds and fior di latte (mozzarella), or even to make a seafood salad. If you want to try an Apulian octopus recipe, prepare octopus alla pignata, an ancient Apulian recipe, the name comes from the typical deep clay pot (the pignatta) in which it was cooked. We of Pescaria used polpo alla pignatta for a limited edition sandwich, with sauce alla Luciana, bufala taleggio cheese and sautèed chicory.
Octopus sandwich, a must for Pescaria
The octopus sandwich is an excellent example of fish street food! We of Pescaria suggest it in a new version created by the chef Lucio Mele: fried octopus, broccoli rabe with garlic and oil, cooked fig must, ricotta and pepper, anchovy oil.
We also serve roasted octopus paired to tomato caprese, fior di latte(mozzarella), oregano, fresh basil lemon oil and we often use octopus for the menu of the day: we put them on seafood friselle paired with seasonal vegetables and a homemade sauce, we use it as ingredient in our seafood croissant with ricotta, zucchini alla poverella, mustard and honey sauce or with apple ceviche, pink sauce, caramelized onion. The fried octopus sandwich is the best seller on the menu of Pescaria, as well as being the first sandwich to be tasted when we opened. If you want to taste it, order with Glovo (delivery), or order for a take away, or come visit us in one of our restaurants: we are in Polignano, Trani (Puglia), Milan (Via solari and Via Bonnet), Turin, Bologna, Naples, Veron, Trento, Padua.