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.

There are tens of thousands species of fish around the world, whether it's in an aquarium, river, lake, or ocean. Like all animals (and humans), every single one needs some form of rest for cognitive ...

Sleep is thought to be vital for the health of animals including us, but one kind of cavefish can somehow manage without it. Yet the cavefish appear to be healthy despite this lack of sleep, with ...

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 ...

Despite decades of research, scientists admit that they still have a lot to learn about sleep. In general, sleep can be defined as a period of reduced activity that is relatively easy to reverse.