The octopus is a lively, interesting animal, but is it the same when it sleeps? While humans toss and turn during the night, octopuses actually change colors to show their mental state. New research shows that this color-changing might be proof of dreaming from the creatures. Their two major alternating sleep states are quiet sleep and active sleep, but what does that even mean?
"During ‘quiet sleep’ the animal is very quiet, with pale skin, and the eye pupil is contracted to a slit," said senior author Sidarta Ribeiro of the Brain Institute of the Federal University in Rio Grande do Norte, Brazil. "The second state is an ‘active sleep,’ in which the animals dynamically change the skin color and texture and move both eyes while contracting the suckers and the body, with muscular twitches."
Unfortunately, the dreams they have probably aren't as plot-driven as ours are.
"If during this state there is any dreaming going on, it should be more like small video clips, or even gifs," says Meridos. So, these animals, once experiencing a REM sleep cycle, have short brain clips playing in their head. What a sweet little dream!