It may look a bit eerie – the image of whales just hanging in the water column – but this is actually normal for sperm whales. The entire pod takes brief, 12-minute or so naps to get their required sleep. Since their respiratory system is voluntary, they have to keep part of their brains awake in order to breathe. It’s even been noted that while in this sleeping state they show signs of REM sleep – you know, the stage of sleep wherein we humans dream. I wonder what whales dream about….
