Marine mammals like Manatees exhibit unihemispheric sleep (one hemisphere is induced to sleep while other hemisphere is awake) because they have to come to the surface to breathe, to enjoy the restorative benefits of sleep while still being on lookout

Marine mammals like Manatees exhibit unihemispheric sleep (one hemisphere is induced to sleep while other hemisphere is awake) because they have to come to the surface to breathe, to enjoy the restorative benefits of sleep while still being on lookout