Octopus civilizationA smart species with no inherited memory

Octopuses are clever but live under two years, and mothers die after their eggs hatch. How could patterns carry memory? The real research behind the game.

Octopuses are clever, yet they have almost no chance to teach what they learn to the next generation. They live only one to two years, and the mother guards her eggs until they hatch and then dies. The game's "Octopus civilization" starts from this fact and asks: what if octopuses could keep their memories?

This page keeps two parts apart. The first is real octopus biology, and every item comes from the "real basis" of a node in the game. The game lore (octopuses actually developing a civilization) is marked separately. The "Related real research" at the end lists a few scientific findings related to the topic. They are not evidence for the octopus civilization idea.

The octopus body: a spread-out intelligence

Arm autonomy: of the roughly 500 million neurons, two thirds are in the eight arms. A severed arm can still make grasping movements in response to stimuli.
Inter-arm nerve ring: the bases of the eight arms are linked by a ring of nerves, so arms can exchange signals with each other without going through the brain.
Copper blood: octopus blood is blue, and the oxygen carrier is copper-containing hemocyanin. An octopus has three hearts, two of which serve only the gills.
Coming ashore: one kind of octopus leaves the water and "walks" on its arms across rocks between tide pools.

Skin that talks, eyes that may not see color

An octopus's skin has thousands of muscle-controlled chromatophores, and it can change color and pattern in less than a second. Interestingly, most octopuses have only one light-sensitive pigment and probably cannot see color, yet they can see the polarization of light. How they turn themselves into the color of the background is still unsettled.

Mimicry is the showpiece of this ability. The mimic octopus, discovered in Indonesia in 1998, can imitate the look and movements of lionfish, sea snakes and flatfish. Cuttlefish, on the other hand, seem more like they are "talking": when courting or confronting a rival they rapidly "play" patterns across the body, such as dark bands that flow along it, called "passing cloud".

A 2021 study also found that octopuses have two sleep states. In "active sleep", the skin quickly cycles through patterns, as if replaying the day's experiences.

Tools, homes and settlements

Octopuses choose or dig dens and block the entrance with stones and shells. In 2009 scientists in Indonesia filmed veined octopuses carrying half a coconut shell clamped beneath their bodies and hiding inside when danger came, one of the earliest records of tool use by an invertebrate.

In 2017 a settlement of gloomy octopuses was found in Jervis Bay, Australia: a dozen or so octopuses living together and building dens from piles of discarded shells. Researchers called it "Octopolis". A shell pile is just leftover waste, yet archaeologists often read the lives of ancient people from human shell middens.

Why the mother dies

A 1977 experiment found that female octopuses stop eating and die after laying eggs. The cause is the optic gland behind the eyes. When the optic glands were removed, the females resumed eating and lived longer. This is the biological reason octopuses have "no previous generation".

A more striking discovery came from the deep sea. A study published in 2023 showed that thousands of brooding pearl octopuses had gathered at a hydrothermal spring about 3,200 meters deep off California. The warm water lets the eggs hatch in under two years, where in the cold deep sea it would take 5 to 8.

The idea in the game: Octopus civilization

What follows is game lore, not something that really happened. In the game, this channel is located in "Earth's oceans". Its resource is Patterns, and it is discovered by unlocking "Octopus civilization" in the Tree of Civilization, which requires protecting the cephalopods through 3 mass extinctions. The core mechanic is the generation gap: with each generation (about 30 minutes), only part of the "Patterns" that were not carved into the body or the environment survive. The more memory nodes you unlock, the more gets passed down.

In the game's scenario, octopuses first review the day's experiences in their dreams. The patterns gradually become words that can be combined, then are carved into stone, and finally the octopuses notice the upright animals on the shore. The scenario has two endings, one living together with humans and one retreating into the deep sea. All of this is fiction. Real octopuses have no civilization.

Two nodes in the channel come from reality and deserve a mention. Human writing was first carved on clay tablets and turtle shells, which let knowledge outlive the person who wrote it for the first time. Tides are caused by the gravity of the Moon and the Sun, and on most coasts the sea rises and falls twice a day.

Twenty Thousand Leagues Under the Seas (Jules Verne, 1870): giant squid are real, and a live one was first filmed in the wild only in 2004.
Children of Ruin (Adrian Tchaikovsky, 2019): the octopus's distributed nervous system and color-changing ability are real. Octopuses evolving language and civilization is fiction.

The studies below relate to the theme of the octopus civilization, because the channel's discovery condition requires protecting the cephalopods through 3 mass extinctions. They are about major events in the history of life, not proof of the octopus civilization idea.

The end-Cretaceous layer is rich in iridium, and Alvarez and his son concluded that an asteroid had struck Earth (Alvarez et al., Science, 1980).
Under Mexico's Yucatán Peninsula lies a crater about 180 km across, exactly where that asteroid hit (Hildebrand et al., Geology, 1991).
The end-Permian mass extinction may have lasted only about 60,000 years, matching the timing of Siberian volcanism (Burgess, Bowring and Shen, PNAS, 2014).
Rock layers in Namibia show that about 700 million years ago Earth may have been almost entirely covered in ice (Hoffman et al., Science, 1998).
Cholesterol-type molecules preserved in Dickinsonia fossils show that this mysterious organism was an animal (Bobrovskiy et al., Science, 2018).

Real basis

Den: Octopuses pick or dig out dens and block the entrance with stones and shells.
Chromatophores: Octopus skin holds thousands of muscle-controlled pigment cells, and can change color and pattern in under a second.
Arm autonomy: Of its roughly 500 million neurons, two-thirds are in the eight arms. A severed arm can still make grasping motions in response to a stimulus.
Copper blood: Octopus blood is blue; the oxygen carrier is copper-based hemocyanin. It has three hearts, two of them just for supplying the gills.
Coconut armor: In 2009, scientists in Indonesia filmed veined octopuses carrying half a coconut shell under their bodies and hiding inside it when in danger. It is one of the earliest records of tool use by an invertebrate.
Mimicry: The mimic octopus, found in Indonesia in 1998, can imitate the look and movements of lionfish, sea snakes and flatfish.
Inter-arm nerve ring: The bases of the eight arms are linked by a ring of nerves, so arms can exchange signals without going through the brain.
Polarization vision: Most octopuses have only one light-sensing pigment, so they probably can't see color, but they can see the polarization of light. How they turn themselves into the color of the background is still unsettled.
Color-changing dreams: A 2021 study found octopuses have two sleep states. In “active sleep” the skin quickly cycles through patterns, as if replaying the day.
Octopolis: In 2017, a colony of gloomy octopuses was found in Jervis Bay, Australia: a dozen or so octopuses living together, building dens from leftover shells. Researchers called it “Octopolis”.
Shell record: A shell pile is just leftover garbage, yet archaeologists often read ancient lives from human shell middens.
Skin language: Cuttlefish quickly “play” patterns across their bodies when courting or confronting rivals, such as dark bands rolling over the body, called “passing clouds”.
Hot-spring nursery: A study published in 2023: around 3,200 m deep, beside hot springs off California, thousands of pearl octopuses were brooding eggs. The warmth hatches the eggs in under two years, where in the cold deep sea it would take 5 to 8.
Coming ashore: One kind of octopus leaves the water and “walks” on its arms across rocks between tide pools.
Optic gland: A 1977 experiment found that a female octopus stops eating and dies after laying eggs, caused by the optic glands behind her eyes. With the glands removed, they resumed eating and lived longer.
Patterns on stone: Human writing was first carved on clay tablets and tortoise shells, letting knowledge outlive the person who wrote it for the first time.
Tide calendar: Tides are caused by the gravity of the Moon and the Sun; on most coasts the water rises and falls twice a day.
Twenty Thousand Leagues Under the Seas (Jules Verne, 1870), the science: giant squid are real, and a living one was first filmed in the wild only in 2004.
Children of Ruin (Adrian Tchaikovsky, 2019), the science: the octopus’s distributed nervous system and color-changing ability are real; octopuses evolving language and civilization is fiction.

Related research

These studies relate to this topic but are not direct proof of this page.

Snowball Earth: Rock layers in Namibia show that about 700 million years ago Earth may have been almost completely covered in ice.
Source: Hoffman et al., Science 1998, "A Neoproterozoic snowball Earth"
The dinosaur extinction puzzle: Iridium is anomalously enriched in the end-Cretaceous layer, and the Alvarezes, father and son, concluded that an asteroid had hit Earth.
Source: Alvarez et al., Science 1980, "Extraterrestrial cause for the Cretaceous-Tertiary extinction"
Finding the crater: Buried under Mexico's Yucatán Peninsula is a crater about 180 km across, exactly what that asteroid left behind.
Source: Hildebrand et al., Geology 1991, "Chicxulub Crater: A possible Cretaceous/Tertiary boundary impact crater on the Yucatán Peninsula, Mexico"
The earliest animals: Dickinsonia fossils preserve cholesterol-type molecules, proving this mysterious creature was an animal.
Source: Bobrovskiy et al., Science 2018, "Ancient steroids establish the Ediacaran fossil Dickinsonia as one of the earliest animals"
The worst mass extinction: Precise dating shows the end-Permian extinction may have lasted only about 60,000 years, matching Siberian volcanic activity.
Source: Burgess, Bowring & Shen, PNAS 2014, "High-precision timeline for Earth's most severe extinction"

Game lore (fictional)

Node “Color-changing dreams”: They rehearse in their dreams.
Node “Shell record”: Here, the way shells are arranged becomes a symbol for keeping records.
Node “Skin language”: Patterns become words that can be combined.
Node “Elders”: The signal from the optic gland is rewritten. Mothers live until their young are grown, and octopuses have a “previous generation” for the first time.
Node “Patterns on stone”: They carve the words from their skin into stone.
Node “Tide calendar”: Octopuses on the shore keep time by the tides.
Node “The people on shore”: They notice the upright animals on the shore, and see their boats and lamps.
Node “Ocean civilization”: Eight arms each think for themselves, then decide together. It is a kind of civilization completely unlike the human one.
Channel ending “Symbiosis”: Humans and octopuses learned to talk with patterns and gestures. One civilization walked onto land on two legs; the other guards the ocean with eight arms. This run, the main civilization’s “Civilization” and “Interstellar civilization” output +15%.
Channel ending “Deep sea”: The octopus civilization withdrew into depths humans cannot reach. Centuries later, a human submersible happens to film a seafloor carved with patterns that no one can read.
Summary of the novel Twenty Thousand Leagues Under the Seas: A naturalist is captured by the mysterious submarine Nautilus and travels the ocean floor with Captain Nemo, even fighting a battle with a group of giant cephalopods.
Summary of the novel Children of Ruin: Humans uplift octopuses on a distant planet and give them intelligence. Their minds are as scattered as eight arms, and they communicate through shifting skin patterns.

See it in the game