51�Թ�

Mice are nocturnal and are "polyphasic sleepers" -- napping for a few minutes before arousing briefly to survey their environment and then resuming their slumber.

Some have pushed polyphasic sleep as a way to “biohack” the body and extend waking hours.

Some skeptics of the natural polyphasic sleep theory point to contradictory evidence found among modern hunter-gatherer populations.

Niall Boyce, an English professor at the University of London, argued that polyphasic sleep may not necessarily have been the norm.

Whether polyphasic sleep exists among modern humans is also up for debate.