Scientists in Japan have discovered that octopuses actually dream, as observed by the odd patterns of chromatophores that ripple across their pale skin while they sleep. They also studied the rapid eye movement (REM) and neural activity of a sleeping cephalopod through brain recordints, noting the similarities to a human dream state.
When octopuses sleep, strange patterns sometimes flicker across their skin. Now, neuroscientists have been able to peer into the brain of a sleeping octopus for the first time – and explore this strange sleep state. They find remarkable similarities to the way that humans and other vertebrates sleep, despite the millions of years of evolution separating the two groups.