Study suggests octopuses dream as they change colour during sleep

Octopuses possess remarkable camouflage abilities, being capable of changing the size of skin projections, altering their coloration, and creating various textures. This enables them to disguise themselves and become nearly invisible, a skill they employ while communicating or when sensing danger.

The unique trait of changing colors is shared by most cephalopods, but octopuses exhibit exceptional resolution and rapidity in their color patterns. While we have witnessed their camouflage abilities while they are awake, the question arises: do they also camouflage while asleep?

A study sought to explore this aspect and proposed that octopuses may indeed dream, similar to humans. The researchers suggest that when octopuses change color during sleep, it may indicate they are experiencing dreams.

The study revealed that octopuses undergo similar skin pattern changes while sleeping, implying the possibility of a dreaming-like state. The researchers speculate that the color-changing process during sleep could be the octopuses practicing their skin patterns to enhance their camouflage behavior when awake.

Alternatively, they might simply be dreaming, reliving and learning from their waking experiences.

To investigate this phenomenon, the Okinawa Institute of Science and Technology (OIST) collaborated with the University of Washington to study the brain activity and skin patterning of sleeping octopuses. Professor Sam Reiter, the senior author of the study, explains that the octopuses’ skin pattern serves as a visual representation of their brain activity during sleep, whereas humans can only verbally report their dreams after waking up.

Reiter, who leads the Computational Neuroethology Unit at OIST in Japan, adds that while all animals seem to exhibit some form of sleep, with even simple creatures like jellyfish and fruit flies displaying sleep-like behavior, for a long time, only vertebrates were known to transition between different sleep stages.

The researchers discovered that the octopuses’ brain activity and skin patterning during sleep closely resemble those observed when they are awake. They verified the sleep state of the octopuses and assessed their response to physical stimuli to support their findings.