An image of an octopus swimming in the ocean. Depositphotos.

Octopuses Sleep Similarly to How Humans Do

It seems that octopuses have more in common with humans than we initially thought.


Much like humans, octopuses seem to oscillate between two distinct stages of sleep — a tranquil phase and an animated one akin to REM sleep in mammals. In other words, Octopuses sleep similarly to how Humans do. But does this suggest the fascinating possibility of these marine creatures dreaming?

Octopus Sleep Similarly to How Humans Do

As octopuses slumber, brief episodes of intense activity occasionally interrupt their quiet repose. Their arms and eyes jerk spasmodically, their respiratory rate increases, and their skin pulsates with vivid hues.


Recently, a research team from the Okinawa Institute of Science and Technology (OIST), together with the University of Washington, meticulously studied the cerebral activity and skin patterns of octopuses (Octopus laqueus) during these active sleep intervals. The findings, intriguingly, mirror neural activity and skin behavior observed during wakeful periods. This wake-like activity also appears during REM sleep in mammals, the sleep stage where dreams predominantly occur.

Waking Up to Sleep’s Secrets

Published on 28th June in Nature, the study illuminates the striking parallels between the sleeping patterns of humans and octopuses. It provides insightful revelations about sleep’s origin and purpose.

“All animals display some form of sleep, from simple organisms like jellyfish and fruit flies to more complex ones. However, the concept of cycling between two distinct sleep stages was thought to be exclusive to vertebrates,” explained Professor Sam Reiter, the senior author and head of the Computational Neuroethology Unit at OIST.

Unveiling Sleep’s Underwater Enigma

The groundbreaking insights into octopus sleep were sparked by a visit to OIST from Dr. Leenoy Meshulam, a statistical physicist at the University of Washington.


“Considering that two-stage sleep has evolved independently in creatures as divergent as octopuses and vertebrates, it suggests that an active, wake-like sleep stage may be a common characteristic of advanced cognition,” noted Dr. Meshulam.

Sleep Stages Under the Sea

Initially, the scientists sought to verify that the octopuses were genuinely asleep during these active periods. They gauged the octopuses’ reactions to a physical stimulus and discovered that the creatures required a higher stimulus intensity before responding, whether in a quiet or active sleep stage, than when awake.

“This compensatory behavior affirms the active stage as a critical sleep stage necessary for octopuses’ normal function,” said Aditi Pophale, co-first author of the study and a Ph.D. student at OIST.

Brain Waves and Skin Waves

The researchers also explored the octopuses’ brain activity when awake and asleep. During serene sleep, the scientists detected characteristic brain waves akin to sleep spindles observed in mammalian brains during non-REM sleep. Although the exact role of these waveforms is yet to be deciphered, they are believed to play a part in memory consolidation.

Dreaming of Patterns?

The team also captured and scrutinized the octopuses’ shifting skin patterns in ultra-high 8K resolution during their awake and sleep states.


“When awake, octopuses manipulate thousands of tiny pigment cells in their skin, enabling a multitude of skin patterns. During active sleep, the scientists noted that the octopuses cycled through the same skin patterns,” explained Dr. Meshulam.

The parallels between active sleep and wakeful states suggest intriguing theories. Are the octopuses practicing their skin patterns to enhance their wakeful camouflage behavior, or merely maintaining the pigment cells? Or, more tantalizingly, are they replaying and learning from their waking experiences, such as hunting or evading a predator, and recreating the skin pattern associated with each experience — much like dreaming?

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Written by Ivan Petricevic

I've been writing passionately about ancient civilizations, history, alien life, and various other subjects for more than eight years. You may have seen me appear on Discovery Channel's What On Earth series, History Channel's Ancient Aliens, and Gaia's Ancient Civilizations among others.

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