Octopi are impressive creatures – They have eight limbs, blue blood, they can squirt ink, they can adapt their skin to work as camouflage, they have three hearts, and they tragically die after mating.
A study carried out by researchers from Brazil posted on Thursday revealed that the octopus, already considered one of the most intelligent invertebrates to live on Earth, experienced two significant alternating sleep states very comparable to those of humans, and they may even be capable of dreaming.
The discoveries provided new evidence that the octopus has advanced neurobiology that proves a very complex behavioural repertoire. It also includes extra insight regarding the evolution of sleep, a fundamental biological function.
Octopi previously were known to undergo sleep cycles and alternate colours while slumbering. In the new study, the researchers noticed a species known as Octopus Insularis in a laboratory environment. They discovered that the colour changes are associated with two individual sleep states – “quiet sleep” and “active sleep,” which usually last for less than a minute.
According to the researchers, the cycle seems analogous as they mentioned the “rapid eye movement” or REM and the “non-rapid eye movement” or non-rem sleep states that occur in people as well as other mammals, reptiles, and birds.
Vivid dreams happen during REM sleep.
The study’s lead author, Sylvia Medeiros, said:
“If octopuses indeed dream, it is unlikely that they experience complex symbolic plots like we do.”
“‘Active sleep’ in the octopus has a very short duration, typically from a few seconds to one minute. If there is any dreaming going on during this state, it should be more like small video clips or even GIFs,” she added.