Senior Editor

The Inertia

Octopuses, as you’re likely aware, are incredibly intelligent. So when researchers studying them noticed that they routinely changed colors in their sleep, they came to the conclusion that they were likely dreaming. But now, after a few more sleep studies, they think they might not only be having good dreams, but bad ones too.

The study — which, it should be noted, hasn’t yet been peer reviewed and only looked at one animal — was done on a male octopus named Costello that lives at The Rockefeller University in New York City. It was captured a few years ago off the coast of Brazil and moved to its new home in a tank.

For three months, 24 hours a day, seven days a week, cameras filmed Costello’s daily movements. Scientists reviewing the footage noticed that he often would change colors and patterns as he slept, leading them to believe that he was “dreaming and physically reflecting the contents of its dream through its body language.”


But in some of that footage, they observed that Costello would wake up with a start, then fling his arms around and squirt out ink, the same as he would do in the wild if he was attempting to escape a predator.

“The behavioral sequences displayed by this octopus upon emerging from disturbed sleep were similar to behavioral responses to nightmares, night terrors, and other parasomnias in humans, with a narrative structure resembling waking defense behaviors in octopuses,” the authors of the study explained. “We speculate that the complex behavioral sequences displayed in these episodes suggest octopuses experience parasomnias which may include nightmares with the potential to disrupt their sleep.”

Since the study only looked at the solitary octopus, it’s not possible to say that this behavior affects all of them, let alone other cephalopods. But it isn’t hard to believe that octopuses do indeed have dreams about good and bad things, just as we do.


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