Schweid - Octopus

When you watch an octopus, an octopus watches you back. A surprising degree of unanimity on this point exists among people who spend a lot of time observing octopuses (the generally accepted plural spelling for octopus). They all agree that when they do so, the animals closely observe them in turn. Gazing for any length of time at an octopus, particularly Octopus vulgaris, the common octopus the species most Europeans, Americans and Asians know leads to the inescapable conclusion that the animal is looking back, and is somehow thinking about what it is seeing. Jacques Cousteau, who encountered thousands of octopuses during his lifetime of diving, wrote in his book Octopus and Squid: The Soft Intelligence (1973) that an undersea diver who encounters an octopus immediately senses something unusually responsive in its gaze: One has the sensation of lucidity, of a look much more expressive than that of any fish, or even any marine mammal.

No researcher working with octopuses remains oblivious to the fact that he or she is under observation, no matter how rigorous and rational their scientific approach. Roger Hanlon, a senior scientist at the Marine Biological Laboratory in Woods Hole, Massachusetts, has been working with octopuses since 1968. He is widely considered to be among the most judicious and careful of current octopus researchers, and his book Cephalopod Behavior (1996) is still the standard reference work in the field. Even he writes that there is something disconcerting about being regarded by an octopus: anyone who has seen an octopus in an aquarium will have had the uncanny impression of being carefully watched.

Octopus in a fresco in Voronet, monastery, Romania, mid-16th century.

Mosaic from a ruin at Pompeii.

The octopus itself is an ancient invertebrate marine animal. Like their close relatives, squids and cuttlefishes, octopuses belong to the cephalopodan class of coleoid molluscs. The name is derived from the Greek words kephale and podus, meaning head-footed, and refers to the fact that the animals arms are directly connected to its head. The class consists of squids, cuttlefishes and octopuses along with nautiluses, the only group of the four to have shells.

Scuba divers regularly report handling octopuses.

Currently some 100 species are identified as members of the genus Octopus, and another 200 belong to other genera. Octopuses live in all the worlds oceans at a variety of depths. The Hawaiian day octopus (Octopus cyanea) lives in shallow tide pools, while the spoon-armed octopus (Bathypolypus arcticus) can be found on the dark Atlantic Ocean floor at 800 m (0.5 miles) deep. Octopuses also come in all sizes. At the small end of the scale is the tiny Atlantic pygmy octopus (Octopus joubini), with a mantle length of 4.5 cm (1.8 in) and arms of 9 cm (3.5 in), or the even smaller California Lilliput octopus, Octopus micropyrsus, which is about 2 cm across, while the giant Pacific octopus (Enteroctopus dofleini) can weigh over 45 kg (100 lb) and measure well over 6 m (20 ft) between the tips of its arms. Reproductivestrategies differ, even among close relatives. With the exception of the Mediterraneans football octopus (Ocythoe tuberculata), which hatches its eggs internally and gives birth to live young, all other octopuses are oviparous, hatching their eggs externally. The Verrills two-spot octopus (Octopus bimaculatus), which lives on rocky reefs from California to Panama, produces 20,000 tiny eggs at a time, while the closely related California two-spot octopus (Octopus bimaculoides) opts for 800 large eggs. While all octopuses use some measure of camouflage for defence, none of them equal the ingenuity of the mimic octopus (