Originally Posted by
Abra
I was under the impression that dolphins did not dream because they are never fully asleep (they have to voluntarily breathe), and that only one hemisphere of the brain undergoes sleep-like EEG activity at a time. But the EEG activity known as REM does exist, just in half the brain at a time. Which leads me to wonder if dreaming is actually possible when one part of the brain is awake, and the other asleep. I browsed a variety of sources, but the results were inconclusive. It appears that the idea that dolphins don't have REM has been disproven, but the idea that they can dream with their unique system of sleep has not been researched conclusively (I have not seen anything confirming a dream state, but I have seen pages that condemn it).