Although fish still can’t close their eyes today (simply because they don’t have eyelids), changes in the brain and muscular systems take place just like humans do when we fall asleep.
Scientists have observed similar behavior in mammals, birds and reptiles, but when they discovered that zebrafish do the same, they discovered that sleep has a very ancient origin. , rather than a new mechanism that evolved in organisms recently.
Sleep has very ancient origins.
“If the ancestors of modern mammals appeared 70 million years ago, the ancestors of fish must have appeared on earth about 450 to 500 million years ago,” said report author Philippe Mourrain of the University of Stanford (USA). Like humans, fish relax their muscles, slow their heart rate and become unresponsive to external stimuli during sleep. The biggest difference is that fish do not appear to have rapid eye movements during the REM stage (the stage that has just ended the deep sleep during sleep – NV) like us.
“When our team found that brain and body motor mechanisms were similar in zebrafish and humans, it meant that nerve and muscle signals were more likely to be lost. present in the common ancestor of animals more than 450 million years ago” , according to The Independent , citing Dr. Mourrain.
Although researchers have so far not determined whether all animals go to sleep or simply take short naps, it can be concluded temporarily that sleep is a common need for all species. .
Experts also do not know the benefits that sleep brings, or rather why people need sleep is still a great mystery. However, people who do not get enough sleep suffer from conditions such as temporary memory loss, impaired judgment, and an increased risk of obesity and high blood pressure.