A protective mucous cocoon surrounds this parrotfish as it sleeps in Australia's Great Barrier Reef. This layer of protection helps fend off predators so parrotfish can get a good night's rest.

Sleep is one of the most essential parts of being human. Catching some Z’s is important for daily functioning. As adults, we've got to get in about eight hours a day, according to the Sleep Foundation ...

Tom has a Master's degree in Journalism. His editorial work covers anything from archaeology and the environment to technology and culture. Tom has a Master's degree in Journalism. His editorial work ...

Do fish with no eyelids sleep? Given that they spend their entire lives submerged in water, this is a reasonable question to ask. Do fish with no eyelids sleep? Given that they spend their entire ...

Researchers have discovered that some fish -- unlike humans -- do not need orexin to stay awake. This molecule was thought to be necessary for normal wake and sleep rhythms in vertebrates. Humans ...

For animals without eyelids, fish are surprisingly capable of catching some serious shut-eye. When zebrafish (Danio rerio) doze off, they catch their z’s much like people do, new research shows. These ...

One of the big, unsolved mysteries in science is exactly why humans and other animals sleep. There are plenty of hypotheses: it’s believed sleep is important in letting our organs repair themselves ...

An intriguing new study is offering insights into the origins of sleep, for the first time discovering zebrafish brains shift through several brain states while sleeping. The researchers suggest these ...

Sleep in fish may look different from humans, but rest is essential for survival. Here’s what experts have to say about fish sleep. A protective mucous cocoon surrounds this parrotfish as it sleeps in ...