The Octopus

Characteristics

The body is shaped like a rounded sac, at the base of which the head protrudes, with the mouth opening at its centre. Around the mouth spreads the mantle, from which eight very strong tentacles radiate, tapering towards their tips.

Along the underside of each tentacle run two rows of disc-shaped suckers, which the animal uses to grip the seabed or any object within reach. The eyes, fairly small and slightly protruding, are set rather far apart, but positioned so as to give a perfect view both sideways and ahead.

There are no fins of any kind: the octopus moves using its tentacles and its siphon, an organ that pumps water over the gills and lets it move by “jet propulsion” when the stream of water is expelled hard and fast. Jet swimming happens backwards, and the apparently clumsy, bulky cephalopod turns into a streamlined torpedo, body and tentacles stretched along a single axis.

The mouth is shaped like a parrot’s beak: a double, extremely strong jaw with which the octopus breaks open the defences of the molluscs it feeds on and can even pierce the shells of crustaceans. For self-defence it has a gland that secretes ink, a dense black liquid that spreads quickly through the water and blocks the view just long enough for our friend to slip away into a crack in the rock.

With its arms outstretched, an average octopus measures around fifty centimetres, but much larger ones are easy to come across: in the Mediterranean these animals can reach three metres in length and twenty-five kilos in weight. These are exceptional specimens, of course, and in any case have nothing to do with the giant squid made famous by so many adventure novels. We know giant squid exist only because huge fragments of their bodies have been recovered; in reality they live at such depths that no human eye has ever seen one whole.

So, relax. An octopus two or three metres long is undoubtedly an impressive beast when seen through the glass of a diving mask, but it is one that is unlikely ever to become truly dangerous. Not least because the octopus has a gentle nature and is more intelligent than any fish: why would it pick a fight with a creature as monstrous (underwater speaking, of course) as a diver?

The fact is that the octopus, like the moray eel and the shark, has fallen victim to the imagination of many writers, who for years have speculated about its supposedly hideous (says who?) appearance. Now and then a small octopus clings desperately to the foot of some unsuspecting bather strolling along the shoreline. Hence its reputation as a terrible creature that brazenly attacks even humans. In reality, if anything, it is the other way round.

Imagine being in the octopus’s place, on a seabed under just a few centimetres of water, and suddenly seeing the enormous bulk of a person about to crush you mercilessly. What would you do? With no time to escape, you would attempt a desperate defence. How? By trying to hold the enemy back, clinging with all your strength to the part of it most within reach of a tentacle: the foot. And so a trivial incident gets blown up and dramatised, turning the octopus into a sinister villain from horror stories.

The skin of this cephalopod is normally smooth and covered in mucus, which makes it slimy. Its colour is generally greyish. However, the octopus can appear wrinkled and covered in bumps, and the grey can turn green, purple, deep red, light brown or black, depending on the seabed it is on and the dominant colours around it. Its camouflage is exceptional and unrivalled in the underwater world. A ten-kilo octopus can be invisible even a few centimetres away, especially to an untrained eye. Surrounded by seaweed, it takes on the look of seaweed; among stones, it blends in with the stones.

The octopus is a solitary animal that likes to live on its own, except in the mating season. Then, having found the right partner, it lives in company for a while and gives itself over to passionate embraces, all twisting and sensual caresses. A tangle of tentacles that might suggest who knows what struggles of the deep, when in fact it is nothing but an expression of the greatest tenderness.

The octopus’s fiercest enemies are the grouper and the moray eel, which attack it furiously. The octopus defends itself by fighting back, puffing itself up to look bigger and more intimidating. Meanwhile it tries to retreat and find a hollow that can take it in and hide it, where its opponents cannot reach. The grouper and the moray aim for the tentacles and try to bite them off. The octopus does everything it can to play for time, waiting for the right moment to vanish into a hole.

In turn, the octopus is the most fearsome adversary of the spiny lobster and the lobster, which it attacks by surprise and immobilises with its eight powerful arms. That, too, is a fight to the death. Once its victim is overpowered, the octopus pierces the shell with its beak and injects the crustacean with a paralysing venom. Then it calmly sucks out the flesh and leaves the shell intact. A gourmet’s meal, in short.

But the octopus’s refinement does not end there. Do you know what our cephalopod does when it wants to enjoy the contents of one of the bivalve shells it is crazy about? The clever creature positions itself in front of the mollusc holding a small pebble in one tentacle, just as if it were holding it delicately between the fingers of a hand. The mollusc senses danger and closes up, but it cannot hold out forever, because it needs to breathe. So after a while, hoping to get away with it, it opens its valves just enough to let in a little fresh water. The octopus seizes the moment and, quick as lightning, with an aim and reflexes worthy of William Tell, throws the pebble between the half-open valves, preventing them from closing completely. Game over: the shell has no way out, because that thin gap is all our gourmet needs to prise the whole thing open in no time.

Habitat

The octopus is common in all the oceans and in all the warm and temperate seas of the world. It can be found from the water’s edge down to several dozen metres deep. Its kingdom is the submerged rocks, especially where rock mixes with seaweed and sand, though it does not disdain muddy stretches either. Whatever its surroundings, the octopus camouflages itself superbly, and its presence often escapes even the most experienced spearfisher. It can even happen that you know for certain an octopus is hiding in a particular square metre of seabed and still not see it, even when searching the bottom from very close up.

The cephalopod hides in caves and the narrowest crevices. It almost always prefers the thin cracks under stones, from which it peers out, perhaps with just one eye, to be less visible to potential enemies. Having no bones, the octopus can literally “pour” itself from one hole to another through cracks so narrow you would think escape that way impossible. The move from one hollow to the next is so incredible that you often feel you are witnessing a miracle or a materialisation experiment: the octopus flattens, lengthens, stretches and spreads out at will, as probably no other sea creature can.

The octopus is crazy about the colour white. When it sees it, it is enraptured, gets excited and throws all caution to the wind. It likes it so much that it tries to surround itself with white, even at home. So you may find an insignificant little hole in the sand ringed with white pebbles, or a crack in a rock closed off with gravel or white shards of pottery. Rest assured: those holes and cracks are the homes of vain octopuses.

Octopuses also go wild for jars and amphorae, preferably ancient ones. Inside these clay vessels they rule the roost and are reluctant to give them up. Fishermen know this and even lower amphorae into the water, tied to lines attached to a float. Every morning the fishermen haul up their amphorae, catch the unlucky tenant and throw them back into the sea, sure of another good catch the next morning.

Another sure sign of an octopus nearby is an unnatural pile of bivalve shells under a stone or against a rock face ending in a small cave between the rock and the seabed. Usually it is the octopus itself that builds such a rubbish heap by its front door. After hunting, the glutton drags its prey into its dining room, eats it at leisure and then gets rid of the inedible parts by throwing them out of the window. Over time, the signs of its settlement become unmistakable.

But beware: if the shells are badly eroded and covered with parasites and all kinds of encrustations, to the point of being fused together, the tenant moved out long ago and there is no point lying in wait. If, on the other hand, the mother-of-pearl is still shiny and intact, the rascal is probably at home, or somewhere very close by.