Octopuses changing skin pattern while asleep may show they dream, research shows

Scientists say the cephalopods have stages similar to REM sleep seen in vertebrates including humans

Octopuses may be the subject of many mariners' nightmares but new research has added to growing evidence the cephalopods may themselves dream while asleep.

Octopuses are thought to undergo two different stages of sleep: quiet sleep" and active sleep", the latter of which involves twitching body parts and rapid changes in the texture and patterning of the skin.