Researchers from the Max Planck Institute for Ornithology and the University of Lausanne announced the somewhat surprising findings on Friday.
In humans, babies spend about half of their sleeping time in REM sleep. But the proportions fall over time. As an adult, you probably spend only about 20 to 25 percent of your sleeping hours in REM.
Rapid Eye Movement (REM) is the lightest stage of sleep recognized in humans because your eyes seem to be moving rapidly underneath your eyelids. Most or all vivid dreaming occurs during REM sleep.
Its purpose is not really known. At the moment, there are many competing theories, including the idea that REM sleep helps young brains develop but serves no real purpose in mature brains.
Whatever the purpose of REM sleep, it must be important. And it must be a relatively old mutation to occur in species as distantly related as barn owls and humans.
Owls don't show the actual rapid eye movement for which REM sleep is named. However, their brain fires in the same way, and the electrical activity can be read on a sensor.
The team performed the study on 66 wild baby barn owls who were collected and fitted with non-invasive sensors originally designed for humans.
And the results were similar. Just as in baby humans, the baby owls enjoyed significantly more REM sleep than older birds.
So far, REM sleep is proved to exist only in birds and mammals.
More research will be needed to find out just what REM sleep does for baby owls -- and for baby humans.