Well, as the article lays out, it's a little more complicated than the leg joints just locking into place. They couldn't figure out how the leg was locking. It'

Well, as the article lays out, it's a little more complicated than the leg joints just locking into place. They couldn't figure out how the leg was locking. It's only when they engaged the lock (by picking up the bird by the shin) that they realized the entire body reconfigures to achieve the needed stability: > When a flamingo shifts onto one leg, two things happen. First, the leg inclines so that the foot moves from being directly under the hip to being directly under the center of the body. Second, the center of mass moves to just in front of the flamingo’s (hidden) knee, so its body weight naturally pulls the hip and knee forward. These two changes, combined with gravity’s pull and the shape of the leg bones, keeps all the joints in place.