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 ...

Group sleeping can impact when animals sleep, how long they sleep for, and how deeply they sleep. For example, groups of meerkats time their sleep according to “sleep traditions”; olive baboons sleep ...

A recent study suggests that zebrafish have four sleep substates, just like humans do—and one of them is akin to an afternoon ...

Humans and other animals encounter and remember countless experiences each day; when we sleep, groups of cells in the brain known as neuronal ensembles replay these experiences to consolidate them ...

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 ...

Humans do very little when we sleep. This might not seem like a big deal, until you look to the dolphins as they sleep and swim with the pod. Or fur seals, who can sleep while watching out for sharks.

Most animals don’t keep the same schedule we do. While we try to squeeze in eight hours and call it a good night, many animals snooze through more than half the day—and some barely stay awake at all.

Animals that navigate extreme conditions and environments have evolved to sleep in extreme ways — for example, stealing seconds at a time during around-the-clock parenting, getting winks on the wing ...