Today’s Wonder of the Day was inspired by Bob. Bob Wonders, “How can flamingos balance with one leg?” Thanks for WONDERing with us, Bob!

We were getting ready to watch the sun set over the Wonderopolis waterfront the other day when we overheard an interesting conversation between a sea gull and a flamingo:

Sea Gull: Hey there! My name's Babs. What's yours?

Flamingo: Nice to meet you, Babs. My name's Frank. I don't think I've ever seen you here before.

Sea Gull: I'm new to the area. If you don't mind me asking, there's something I've always wanted to know about flamingos.

Flamingo: Oh year? What's that? Why we're pink?

Sea Gull: No, I know you're pink because of what you eat. I've always WONDERed why you stand on one leg when you sleep.

Flamingo: Ha! That's a funny story. A flamingo did it once and it made the humans freak out. He posted a video on FlamingoBook and it went viral. Now all the flamingos do it just to mystify the humans!

We firmly believe that Frank was just pulling Babs' leg, but their conversation did make us WONDER about exactly why — and how — flamingos stand on one leg while they sleep.

Standing on one leg is not natural — or easy — for human beings to do for any length of time. Yet, flamingos seem to do it with ease for long periods of time with little or no effort.

Scientists who have studied flamingos have observed this behavior for a long time. Over the years, they even developed several theories about how and why flamingos stand on one leg when they sleep.

Some think that flamingos stand on one leg to dry it off from time to time, since they spend so much time in the water. Others think they stand on one leg because they only turn off one side of their brains when they sleep.

More popular theories concentrate on potential benefits of standing on one leg. For example, some scientists believe standing on one leg conserves energy and reduces strain on the heart, since the heart only has to pump blood all the way down one leg.

Others think it helps flamingos to regulate body temperature. Standing in cold water all day can make it difficult to keep body temperature up where it belongs. Standing on one leg reduces the amount of heat lost to the water, thereby helping to control body temperature.

Another popular theory holds that standing on one leg could be a form of camouflage. From the point of view of fish swimming below the water, a flamingo standing on one leg could resemble a reed or small tree.

For years, all scientists have had are these potential theories. Recently, however, scientists studying flamingos may have made a breakthrough in understanding this peculiar behavior.

Professor Young-Hui Chang of the Georgia Institute of Technology and Lena Ting of Emory University studied the bodies of dead flamingos to learn more about their anatomy. In the process, they discovered it takes less effort for a flamingo to stand on one leg than it does on two.

When you see a long flamingo leg, you're actually just seeing the calf, ankle, and foot. A flamingo's knee is hidden beneath its feathers where you'd imagine its hip would be. The ankle is where you'd expect the knee to be, and it does something unusual. A flamingo's ankle joint snaps shut, locking the foot-to-leg connection in place.

When studying a flamingo corpse, researchers were able to balance it on one leg because its joints naturally aligned so that one leg was positioned beneath the center of the body. Since this could be done with a dead flamingo, researchers concluded that standing on one leg couldn't require any muscle activity at all in live flamingos.

So, unlike humans who have trouble standing on one leg and can only do so for a short time with great muscle strain, flamingos can stand on one leg without any muscle activity at all. Isn't nature interesting? Who would've thought that standing on one leg could actually be easier than standing on two legs?

Wonder What's Next?

When it comes to tomorrow’s Wonder of the Day, the proof is in the pudding!