Every animal with a brain needs sleep — and even a few without a brain do, too. Humans sleep, birds sleep, whales sleep and even jellyfish sleep. Sleep is universal “even though it’s actually very ...

Every animal with a brain needs sleep — and even a few without a brain do, too. Humans sleep, birds sleep, whales sleep and even jellyfish sleep. Sleep is universal "even though it's actually very ...

What has puzzled researchers and philosophers for many centuries is the ‘why’ of sleep, along with the ‘how’. We human animals know from experience that we need to sleep, and that the longer we go ...

Sleeping for only a few minutes at a time? While this might sound like a true ordeal for humans, it's no problem for some ...