I love an animal that makes it difficult to decide which part of it is the strangest. An octopus has eight arms covered in suckers, a body that can fold itself into an alarming number of shapes, and the ability to look remarkably like whatever rock it happens to be sitting beside. Somewhere in that arrangement is a nervous system doing things we're still trying to understand. Honestly, if somebody were designing a creature for a science-fiction movie, I think they'd be told to remove a few features because the audience wouldn't believe it.
That doesn't mean octopuses came from space. They didn't need to, which I find considerably more interesting than the alien story. They're mollusks, part of the same enormous animal group that includes snails and clams, and their unusual biology belongs to the history of life on Earth. The interesting question is how evolution produced an animal whose way of sensing and responding to its surroundings is so different from ours. Apparently, being related to a clam doesn't prevent you from becoming the most fascinating thing in the room.
The Genome Was Strange, but It Was Still an Earthly Genome
In 2015, researchers published a genome for the California two-spot octopus, Octopus bimaculoides, rather than the common octopus, Octopus vulgaris. They identified roughly 33,000 predicted protein-coding genes and expansions in certain gene families, including ones associated with neural development. They also found substantial rearrangements in the genome. Those are exciting findings about how cephalopods evolved, not evidence that their DNA lacks a place in the animal family tree. The authors described innovations built from a broadly familiar genetic toolkit.
A gene count also isn't an intelligence score. It would be wonderfully convenient if we could line up animals according to how many genes they have and immediately settle every argument about cleverness, but biology has declined to organize itself that neatly. What genes do, when they're active, and how their products interact matter enormously. I find the actual story more satisfying anyway: an animal can become very different without needing a completely unrelated set of instructions shipped in from another galaxy.
Different Doesn't Mean Impossible
I think part of the attraction of the alien comparison is that we're accustomed to looking for familiar faces when we talk about intelligence. A chimpanzee using its hands or a dog looking toward a person gives us something recognizable to work with. An octopus reaches around a rock with an arm that can gather chemical information at the same time it makes contact. It's harder to relate to, and I suspect that's part of why I want to keep reading. The challenge is to understand the animal's own problems rather than decide how well it performs our version of being clever.
An Arm Can Gather Information Where It Finds Dinner
A 2020 study by Lena van Giesen and colleagues investigated the molecular basis of the octopus's taste-by-touch system. Researchers identified receptors in the suckers that respond to certain poorly soluble chemicals, helping explain how contact with a surface provides chemical information. That's useful for an animal searching around rocks and crevices where its eyes can't necessarily inspect everything an arm reaches. The same appendage can hold onto something and gather information about what it has encountered, which seems like a pretty impressive arrangement for finding lunch.
The arms also contain extensive nervous circuitry and can handle some responses locally. That's the real idea behind the popular description of an octopus having nine brains, although the phrase can give the wrong impression. There is a central brain, and arm-based processing doesn't mean eight separate little individuals are having independent conversations about dinner. I like thinking about the coordination problem instead. Having eight flexible limbs gathering information in different places sounds useful, but it also sounds like a spectacular amount to organize without getting yourself tied into an embarrassing knot.
As a sommelier, I'm particularly drawn to the chemical-sensing part of this. Taste and smell already make the world richer for us, so the possibility of gathering information through contact in such a different arrangement is fascinating. I'm not suggesting an octopus is taking tasting notes on a crab, although I would very much like to read them if it were. The point is that our familiar categories of seeing, tasting, touching, and deciding don't necessarily divide another animal's experience into the same tidy compartments.
RNA Editing Is Real, and It Doesn't Require a Comet
There's another remarkable feature here: extensive editing of RNA that can change the proteins an octopus makes. RNA helps carry genetic instructions into the process of building proteins, and editing it isn't the same as rewriting the underlying DNA. Other animals, including us, also edit RNA, so the existence of editing itself isn't uniquely octopus biology. What's striking in these cephalopods is the scale of protein-altering editing and what researchers are learning about its function.
In a 2023 study led by Matthew Birk and colleagues, California two-spot octopuses acclimated to cooler water showed increased editing at thousands of sites in their nervous systems. The researchers also examined how particular edits affected proteins involved in neural function. This supports a role in adjusting to changing temperatures, rather than an animal consciously choosing to redesign itself. The Marine Biological Laboratory's account emphasizes gradual environmental changes, not instantaneous adaptation whenever an octopus swims into a colder patch of water.
I love this finding because the real mechanism is already extraordinary. We don't need to add that octopuses rewrite memories on command, become immune to cold, or have access to some secret evolutionary shortcut. A cell changing how it produces certain proteins in response to its environment is plenty to keep my attention. It's also a useful reminder that the familiar drawing of DNA becoming RNA becoming protein leaves out an awful lot of activity. Apparently, the copy is allowed to have revisions, provided the biology does the editing.
The Skin Is Impressive Without Becoming a Thought Screen
An octopus's changing appearance is one of the most visually striking parts of its biology. Pigment-containing structures called chromatophores help create changing skin patterns, while other structures contribute reflective effects and texture. Camouflage and displays are real, but a pattern isn't automatically a sentence, and looking at an octopus changing color doesn't let us read its thoughts. I think that's an important distinction because the temptation to narrate every movement is almost irresistible. A change might look annoyed to us without telling us exactly what the animal is experiencing.
Three hearts and blue blood are real too. Two hearts move blood through the gills, while another circulates it through the body, and the copper-containing oxygen carrier hemocyanin accounts for the blue color when oxygenated. These are working biological systems, not decorations added to make an animal look otherworldly. An octopus doesn't have our skeleton, either, although its hard beak means flexibility still has limits. I wouldn't assume any octopus can squeeze through any coin-sized hole just because the internet has offered a particularly enthusiastic description.
The variety matters as much as the famous features. Octopus is a category containing many species, not one standardized animal living in every ocean under identical conditions. A shallow-water species using a rocky den doesn't tell us everything about one living far below the surface. I catch myself wanting one neat description, then remember how ridiculous it would be to explain every mammal by describing a squirrel. It would cover some useful ground, but the whale would have several reasonable objections.
A Coconut Shell Can Become Something Worth Carrying
One of my favorite examples comes from Julian Finn, Tom Tregenza, and Mark Norman's 2009 report on veined octopuses carrying coconut-shell halves. The animals transported the shells and used them as shelter, behavior the researchers described as defensive tool use. Carrying an awkward object now because it can be useful later is a much more specific observation than simply announcing that an octopus is a genius. It gives us something concrete to examine: what the animal does, what the object provides, and why collecting it might be useful.
There's something particularly charming about the object being a coconut shell. It doesn't look like the sort of thing that should prompt a serious conversation about cognition, yet here we are discussing a marine animal moving around with a potential hiding place. I'm fond of science that makes an ordinary object look different afterward. A shell on the seabed can be debris from one perspective and useful protection from another. We don't need to know whether the animal feels proud of its find to appreciate what researchers observed.
I also wouldn't turn this into a claim that octopuses secretly design cities, speak to coral, or understand construction in the way we do. Those are appealing stories, but they require their own evidence. Rearranging material around a den is already worth studying on its own terms. The question becomes less about whether an octopus is a tiny architect and more about how it responds to shelter, threats, objects, and opportunities. That seems like a much better way of getting to know an animal than handing it a job title.
Sleeping Octopuses Make the Mystery Even Better
In 2023, Aditi Pophale and colleagues reported brain recordings and skin-pattern observations in Octopus laqueus during sleep. The animals alternated between a relatively still sleep state and brief active periods, with changes in movement, appearance, and neural activity. During active sleep, some patterns resembled those seen when awake. The researchers also tested responses to stimulation and observed compensatory sleep after disruption, helping establish that the active periods were part of sleep rather than ordinary waking behavior.
Could that mean an octopus dreams? Possibly, but the study doesn't give us an account of what an octopus experiences while asleep. The researchers discuss several possibilities, including processes related to maintaining skin patterns or reactivating waking experiences. I would love to know whether there's anything comparable to a remembered scene in there, but wanting to know isn't the same as knowing. We can be fascinated by a sleeping animal's changing appearance without deciding that it's definitely dreaming about a particular crab it chased earlier.
That uncertainty is part of the appeal for me. We're looking at an animal whose nervous system is organized differently from ours, trying to connect observations we can measure with experiences we can't directly ask it to describe. A skin pattern and a recording provide evidence; a little story about its emotional life may be our own addition. There's room to care about the animal while remaining careful about that boundary. In fact, I'd rather acknowledge the mystery than cover it with a confident explanation that turns out to be something we made up.
The Fossil Record Isn't an Arrival Announcement
Soft-bodied animals leave a difficult fossil record, and an incomplete record doesn't mean a modern octopus appeared fully formed without ancestors. Research combines rare fossils with anatomy and genetic relationships to reconstruct cephalopod history. A 2022 paper, for example, described Syllipsimopodi bideni, a roughly 328-million-year-old ten-armed fossil that the authors placed near the early history of the group containing octopuses and vampire squid. Its proposed position is a scientific interpretation, not a preserved modern octopus or a claim that every detail of the family tree is settled.
The broader point is that gaps are questions to investigate. They don't become evidence for a space delivery simply because the animal looks strange. I don't need to treat a speculative extraterrestrial-origin proposal as equally supported by the genome research just because both have appeared in journals. Evidence has to do the work. The same applies to suggestions about quantum thinking, an octopus understanding its own mortality, or a mirror response proving self-awareness. Those conclusions don't follow from the studies discussed here, however interesting the questions sound.
Earth Hasn't Run Out of Strange Ideas
I still think the alien comparison can be useful as a reminder to loosen our expectations. It doesn't tell us what life on another planet actually looks like, but it does show how narrow our instincts can be about what a capable animal ought to look like. We share a planet with something that gathers chemical information through its suckers, changes its appearance, and carries pieces of coconut around for shelter. Meanwhile, I occasionally need considerably more time than seems reasonable to locate something that's sitting directly in front of me.
What I find most exciting is that every genuine explanation leads to another question. Knowing about RNA editing makes me want to know how its effects are coordinated, and knowing about active sleep makes me want to know what happens during those changing patterns. There's a lot left to understand without adding an interstellar backstory. Octopuses are wonderfully wierd animals from Earth, and I think this planet deserves the credit for them. The fact that they're related to other life here makes the whole thing better, not less remarkable.
An octopus plush would be a very enjoyable addition to the shelf after reading this. Eight soft little arms, a face I’m going to get attached to and another excuse to tell somebody what I learned about an animal.
