Add Yahoo as a preferred source to see more of our stories on Google. A protective mucous cocoon surrounds this parrotfish as it sleeps in Australia's Great Barrier Reef. This layer of protection ...

Fish sleep in a "low power mode," maintaining basic functions like breathing, but they don't close their eyes. Providing a consistent light-dark cycle is essential for fish health, as they can ...

By tracking eye movements in zebrafish, researchers identified four different types of sleep, analogous to the complex sleep ...

Fish may lack eyelids, but when it comes to sleep, a new study suggests they're a lot more like humans than you might guess.

The short answer is yes, fish do sleep. But the way they sleep differs from land-dwelling creatures. Unlike humans who have eyelids, fish don't close their eyes when they sleep. Instead, many species ...

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 ...

Humans and other mammals cycle through distinct sleep phases. One of them is easily recognized by the darting motion of the eyes behind closed lids, giving it its name: REM (rapid eye movement) sleep.

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 ...

Contrary to common belief, not all vertebrates regulate their sleep-wake rhythm in the same way. University of Basel researchers have discovered that some fish – unlike humans – do not need orexin to ...