Last updated on March 29, 2020
Flamingoes stand and even sleep on one leg – or unipedal, that is the technical term. They do so for a longer time span than humans could, but why ist that actually possible? Why don´t they fatigue, why is it probably even beneficial? In a recent study, two researchers from the Georgia Institute of Technology in the US took a closer look at this behaviour and got help from their local zoo.
From a biomechanical point of view, it may seem strange: A large body, standing on a small area of support, that usually sounds quite impractical. So the researchers obtained two cadaveric specimen from their local zoo and examined the structure of the knee, gathered data regarding body sway in living flamingoes and made an interesting finding. A group of ligaments in the proximal (near) part of the leg locks into place when the limb is fully extended, leading to no muscular work needed to maintain that position. As long as the foot is placed directly under the body, or more precise when the center of pressure lies in the area of support (the foot), the flamingo can stand with basically no muscular effort. During sleep the flamingo moves even less, thus making it even easier for the mechanism to maintain balance (that´s meant with the term “less sway”).
Their data regarding sway showed that flamingoes stood less stable when they used both legs, yet they did not find an explanation for that. But besides stability, there might be a second benefit from standing unipedal: Some birds use their legs to control their body temperature, this way they are able to loose large amounts of heat energy. That happens even faster when standing in water, something that flamingoes regularly do. Standing on only one leg can therefore be an advantage when the birds aim is to store caloric energy, especially in colder surroundings.
It is interesting to see how a phenomenom that appears biomechanically quite inconvenient at first sight turns out to be an evolutionary advantage. But there are still open questions regarding the behaviour of flamingoes and the discussion is by far not over yet, so we can look forward to hear more about these fascinating animals.
References
Chang, Y. H., & Ting, L. H. (2017). Mechanical evidence that flamingos can support their body on one leg with little active muscular force. Biology letters, 13(5), 20160948.
