A small study conducted in Brazil may indicate that cephalopods have a similar sleep cycle to humans.
Scientists observed that octopuses pulse their skin with a dazzling array of colors when snoozing away on the seafloor. This phase of sleep is very similar to Rapid Eye Movement (REM) sleep in humans. The other part of the cycle is called “quiet sleep,” where the octopus remains still and turns a pale white color.
While humans do most of their dreaming during their REM sleep phase, we don’t know if octopuses dream at all, and if they do, what they dream about.
According to Sidarta Ribeiro, a neuroscientist at the Brain Institute of the Federal University of Rio Grande do Norte, Brazil, and a senior author of the study:
“This whole speculation about dreaming, we must take it with caution. In mammals, the active sleep, what we call REM sleep is much longer. It lasts minutes, dozens of minutes . . . even if there is . . . some sort of inner narrative going on in the octopus’s mind as it’s going through active sleep, it’s very unlikely that it’s a whole story.”
According to Ribeiro, if they dream, it is very likely they dream in a short clip format.
You can check out a video below of a sleeping octopus.