Ducks Sleep With One Eye Open

Sleeping alone is dangerous in the animal kingdom, especially if you’re a duck. With predators lurking nearby, a deep, uninterrupted sleep could be a fatal mistake. That’s why these waterfowl have cultivated a safer sleeping strategy. Like many other animals, ducks are capable of unihemispheric sleep, meaning they rest one half of their brain while the other remains awake. During this time, they literally sleep with one eye open, keeping watch for danger while still getting the rest they need.

Fortunately, ducks don’t need to sleep this way all the time. When sleeping in a group, these birds take guard duty in shifts. They sleep in flocks, with ducks on the outer rim employing this one-eyed sleep to keep watch, while ducks in the middle enjoy a restorative two-eyed sleep.