World Octopus Day Was Invented on a Forum

An octopus carries around 500 million neurons, which is a respectable number for an animal with no bones. What makes it strange is the distribution. Only about 40 to 45 million sit in the central brain. Roughly two thirds are spread through the arms, which taste what they touch, and which can work out the movements to reach a target while the animal is occupied with something else.

That is the animal the eighth of October is named after. The date is a joke about arms, and the day has no institution behind it at all.

A Message Board Made It Up

World Octopus Day was created in 2007 by members of TONMO, The Octopus News Magazine Online, a forum where people who keep, study or simply like cephalopods have posted since the early 2000s. They picked October 8th because eight is the number of arms, and because the days after it gave them a run of dates they could assign to the rest of the group.

That run became Cephalopod Awareness Days. October 8th opens it with the octopus. October 9th is for nautiluses and the other living cephalopods most people cannot name. October 10th covers the ten-limbed animals, squid and the cuttlefish, which carry eight arms and two longer feeding tentacles. October 11th is for cephalopods in myth, which is a generous share of a five-day calendar to hand to the kraken. October 12th closes the run as Fossil Day, timed to land with National Fossil Day, for the roughly 17,000 extinct species known from fossils, ammonites among them.

No charity registered it. No agency endorsed it. A handful of people on a forum decided their animals should have a week and wrote it down, and nearly twenty years later aquariums and marine labs mark it.

The Day Now Has an Argument Attached

For most of its existence the day was a celebration of a strange animal and nothing more. That changed when the welfare question arrived.

In 2021 the London School of Economics reviewed more than 300 studies on invertebrate sentience for the UK government and reported very strong evidence of sentience in octopods. The finding was specific rather than sentimental: octopuses show the behavioral markers used to infer pain in vertebrates, including avoiding places where they have been hurt and seeking out anesthetic afterward.

The UK acted on it. The Animal Welfare (Sentience) Act was extended to cover cephalopod mollusks and decapod crustaceans, which was the first time an octopus had any standing in British animal welfare law.

The report also recommended against octopus farming, and that recommendation has done more traveling than anything else in it. Washington State banned octopus farming in 2024, the first jurisdiction anywhere to do so, and California passed its own ban the same year. Neither state had an octopus farm. Both wrote the law to arrive before one did.

Why Farming Them Is the Wrong Idea Twice

The welfare objection is the one that gets quoted, and it is the weaker half of the case.

An octopus is a strict carnivore. Producing a kilogram of farmed octopus takes roughly three kilograms of wild-caught fish, which means the animal is a net drain on the fisheries it is supposed to relieve. A farm does not add protein to the world. It converts cheap fish into expensive fish at a loss, and applies that loss to stocks already under pressure.

Then the welfare problem sits on top. Octopuses are solitary, territorial and inclined to eat each other in confinement, and there is no established humane slaughter method for them. The combination is why the bans passed with a breadth of support that surprised the people who filed them.

What the Day Is Good For

The honest answer is that it is a hook. Aquariums schedule talks, marine labs open their cephalopod rooms, and a reliable wave of octopus footage goes around every October 8th.

The useful part is that a day invented on a forum turns out to be the one piece of infrastructure the welfare argument had. There is no World Octopus Trust and no octopus equivalent of the pangolin campaigns. The date is the whole platform, and the people using it now are not the ones who made it.

The animal itself has done nothing to earn any of this attention and cannot be told about it. Every octopus in the water is solitary, short-lived, and largely finished by the time it reproduces once. The rest of the body is arranged on the same principle as the nervous system: three hearts, two of them serving the gills alone, and blood that runs blue because it carries copper instead of iron. A giant Pacific octopus gets three to five years. The common octopus gets one or two. Whatever they are, they are not around long enough to accumulate much.

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