Do octopuses dream?
Scientists used to think that only mammals and birds experienced different sleep states. More recent research, however, has revealed some reptiles and cuttlefish -- another cephalopod and relative of the octopus -- show non-REM and REM-like sleep.
A new study has found that the octopus has ‘quiet’ and ‘active sleep’, with different episode duration and periodicity, and experiences active sleep after a long episode of quiet sleep.