Scientists Think Octopuses Might Actually Dream — and the Evidence Is Pretty Wild
Picture an octopus resting on the ocean floor. Its body is pale and still. Then, without warning, colors start rippling across its skin — flashes of deep crimson, bursts of mottled brown, rapid shifts in texture — while its eyes dart and its limbs twitch. It looks like something is happening inside that big, strange brain.
According to researchers, something almost certainly is.
Their Sleep Cycle Looks a Lot Like Ours
Octopuses cycle through two primary sleep states: quiet sleep and active sleep. Quiet sleep is exactly what it sounds like — the animal goes still and pale. Active sleep is the wild part. During this phase, octopuses display visible twitching along with rapid changes in skin color and texture, per NPR.
Despite being separated from mammals by more than 500 million years of evolution, this pattern of rest shows similarities to mammalian sleep. Researchers at the Okinawa Institute of Science and Technology confirmed that octopuses are genuinely asleep during this active phase rather than simply resting, and that the state closely resembles REM sleep in vertebrates, including humans, per The Guardian.
For context, REM sleep in humans is characterized by rapid movements of the eyes, irregular breathing and increased brain activity that closely resembles wakefulness. It is strongly associated with dreaming, according to the National Sleep Foundation.
So when an octopus starts flashing colors and twitching in its sleep, the parallels are hard to ignore.
The Color Changes Might Reveal What They’re ‘Seeing’
Here’s where it gets really interesting. Those skin color changes aren’t random. Neuroscientist Sam Reiter explained the significance to The Guardian: “We can associate certain skin patterns during wakefulness to specific situations: hunting, social displays, threat displays, camouflage to different sorts of environments. We show that these patterns reappear during active sleep.”
The octopus appears to replay its waking life while asleep — cycling through the same visual displays it uses while hunting, hiding or communicating.
Does that mean it’s dreaming? Reiter was careful with his answer. “So, if we are looking at something like dream, and I repeat this is a possibility we do not prove in this study, they would resemble a pseudo random walk over different types of waking experiences.”
The patterns displayed during active sleep often resemble those seen during waking behaviors, supporting the idea that the brain may be reactivating prior experiences. Scientists emphasize that this does not confirm the presence of dreams, though. The observed activity could instead reflect internal neural processes, such as refinement of camouflage abilities.
These Episodes Last Under a Minute
Laboratory observations showed that active sleep episodes occur roughly every 30–60 minutes and last around 40–60 seconds. During these periods, octopuses exhibit rapid skin color changes, shifts in breathing and noticeable eye and body movements.
Graduate researcher Sylvia Medeiros described the behavior: “For around 40 seconds, they dramatically change their color and their skin texture. Their eyes are also moving.” She explained that due to the brief duration, any potential dreams are unlikely to be complex or symbolic, though they may still support memory consolidation and learning.
Neuroscientist Sidarta Ribeiro put it bluntly: “If they are dreaming, they are dreaming for up to a minute.”
One more revealing detail: when deprived of sleep, octopuses enter active sleep more quickly and experience it more frequently. This indicates that the state is homeostatically regulated — meaning their bodies need it.
What This Could Mean for How We Understand Animal brains
Marine biologist Carrie Albertin emphasized the importance of rigorous study: “It’s really hard to deny that something is going on, but it’s really important to actually quantify it and do the study … so that you can characterize it in a rigorous way.” She added that cephalopods are particularly valuable for research because “they are a separate example of the evolution of large brains.”
The presence of a REM-like state in octopuses suggests that complex sleep patterns may not be unique to vertebrates and could have evolved independently. That means dreaming — or something close to it — may have emerged more than once across the animal kingdom in brains that look nothing like ours.
The full extent of what octopuses experience during sleep remains unknown. But the next time you see footage of a sleeping octopus lighting up like a living mood ring, know this: science says there’s a real chance something is playing behind those closed eyes.
This article was created by content specialists using various tools, including AI.
