Best Of Wendy Langhans Reports
It’s the middle of the afternoon. You’ve just finished eating a HUGE meal and you’re starting to feel sleepy. Sound familiar? But what if, instead of a cozy recliner, you’re sitting among the cattails at the edge of a pond? What if, instead of wearing a green and gold Packer’s jersey, you’re wearing green and gold feathers? What if you’re a not a human, but a mallard duck? Would you still want to take a nap, knowing that hungry predators are nearby?
The need for sleep and the danger of predation – it’s a problem faced by many waterfowl. Mallard ducks deal with it in two ways: the first is physiological while the second has to do with social behavior.
Let’s start with the physiological adaptation. According to studies originally conducted at Indiana State University, mallard ducks “exhibit two types of sleep, slow-wave sleep (SWS) and rapid eye-movement (REM) sleep. SWS sleep can occur in one or both brain hemispheres at a time”. In other words, they can choose to “keep one eye open and one half of their brain awake”, a phenomenon called unihemispheric sleep.” This way, they can keep one eye (and half their brain) open and alert for predators while the other half of their brain catches a few zzz’s.
But there’s more to it than just physiological adaptation – social behavior also plays a role. After all, mallard ducks tend to hang out in flocks. Just like a squad of sleeping soldiers post sentries, a flock of ducks does the same. Studies conducted in the lab confirm this: mallards on the periphery of the group turned their “open eye away from the group”. Mallards also “showed a 150% increase in the amount of time spent in unihemispheric sleep”. By “posting sentries”, some of the ducks could spend more time in deeper REM sleep, while the others managed to get at least a little “shut-eye”, while keeping the other eye open for predators.
So if you find yourself in danger of nodding off after a delicious Thanksgiving dinner, I recommend you take a lesson from the mallard’s playbook. Make sure you post a look-out. You don’t want some two-legged predator making off with that last slice of pumpkin pie, now do you?