While sleeping mid-air sounds unbelievable, it is a special adaptation among birds. As reported in a study published in Nature Communications by the scientists at the Max Planck Institute of Animal Behavior, certain species of birds can fall asleep in-flight using unihemispheric slow-wave sleep when one hemisphere of the brain is resting, and the other one remains awake. In this way, they can stay aloft for hours during migration or flights over the sea without losing their navigational abilities. Here are seven species of birds that can sleep mid-flight.
