Why Do Flamingos Stand On One Leg?

We're answering ten questions as quickly as we can in this episode of But Why. Why do onions make you cry? How do hummingbirds hum? Why do flamingos stand on one leg? Do moths have veins in their wings? Do cats that share a home have the same meow? What was the first book? How do libraries get money if people borrow books for free? Why do people have fidget spinners? Why can't my stuffed animal get wet? And how do pigs poop? Can we do it all in 20 minutes?!