How Flamingos Stand on One Foot

Mysteries of the universe unfold: how can flamingos sleep while standing on one foot? And why is it good to know?

It’s surprising how many things in the world are commonly observed but never investigated scientifically. The few who have thought about why flamingos stand on one foot have simply speculated that it helps control body heat when standing in cold water, or helps them save energy by using just one foot at a time. Nobody really measured these ideas, or checked the birds’ anatomy– till now. The story is told by Lena Ting and Young-Hui Chang at The Conversation:

Of course, as humans, we think standing on one leg is hard because it’s difficult for us. Tree pose in yoga becomes increasingly difficult as you lift your leg higher, reach your arms up and tilt your head. It becomes almost impossible if you close your eyes. Most of us wobble and sway, then put a foot down, and shake out the leg we were standing on.

As scientists, the two of us are interested in how the brain controls the body – a field we call neuromechanics, at the intersection of biomechanics and neuroscience. Our latest research question: Just how do flamingos stand on one leg? Our search brought us up close and personal with a flock of juvenile flamingos and even flamingo skeletons and cadavers to figure out how they achieve their amazing feats of balance.

In short, they found that the birds actually save energy by standing on one foot instead of two. The leg is positioned slightly at an angle, under the center of gravity, by bones and joints that form a right angle in the body (unlike our knees and hips). The limb joint locks in one direction, but stays open in the other direction.  Playing with the leg of a flamingo cadaver, Ting and Chang found that the leg was able to balance in an upright position, even when slightly rocked. This indicates that one-legged standing is a “passive gravitational stay mechanism” not requiring active muscle control.

Then, experimenting with live birds on a wobbly platform, they measured the energy expenditure in the one-legged and two-legged postures. Resting or sleeping required very little ‘postural sway’ control, but grooming and undertaking other active moves while awake took up to seven times more. Using two legs actually takes more muscle power than standing on one, they found. And so, with just a minimum of brain control, the flamingo can stand for long periods, and even sleep, on one skinny leg. “Gravity plus anatomy do the job,” they say. They published their findings in the Royal Society’s Biology Letters.

Paul Rincon at the BBC News is not sure the team answered the when, where, and why questions sufficiently, but agrees they did provide new insight on the how question. Why is this good to know? Well, think of those commercials for free-standing canes for senior citizens:

Why do we care? This study was a fun inquiry that revealed how different standing on one leg is for a flamingo compared to a person. As scientists, it’s rewarding to study the wonders of nature and to see how physics and biology are intertwined in the behavior of animals. Still, there are practical lessons that can be learned. Engineered systems with motorized joints and legs, such as some prosthetic devices and humanoid robots, expend quite a lot of energy just to stand up. Perhaps using some principles of flamingo balance could help to design more stable, yet agile and efficient, prostheses and robots.

The study of living things is never in vain. Consider how these other investigations may help us all in our daily lives:

We still have much to learn from biological systems —Science Daily

• Burrowing seeds are giving agriculturalists ideas for more effective means of penetrating the soil (Science Daily). Watch this amazing video of a filaree seed folding itself into a drill and drilling itself into the ground! (YouTube).
• Dandelion seeds make perfect tips for pipettes in chemistry labs (Phys.org, Science Daily).
• Animal eyes are inspiring new camera systems at the University of Glasgow (Phys.org).
• Wood from dead trees killed by beetles may come to life in the form of oil, reports Science Daily.
• Glowing fungi “will stimulate the development of fungal bioluminescence–inspired applications ” (Science Advances).
• Bird feathers‘ tricks of light may show up in your clothing and other materials some day, reports Science Daily.
• Mother-of-pearl, or nacre, is the “gold standard of biomimicry” according to a paper in Scientific Reports sharing the latest advances in imitating its superb materials properties.
• Frog legs, are not just good for food, they are”astonishingly complex” in their ability to jump forward and sideways, reports New Scientist. This will undoubtedly attract robot engineers.
• Venus flytrap leaves have inspired a robotic trap that can grasp and lift objects, says Live Science. It can pick up objects a hundred times its own weight, adds New Scientist.
• ‘Dragonfly‘ is the inspiring name given a prototype drone that may one day explore Saturn’s moon Titan (Space.com).

Would these living things inspire human designers if they were not intelligently designed in the first place?

Parents, kids love to watch frogs jump. Use the opportunity to ask them questions that get them thinking: How does it do that? The more kids learn to ask how questions, the less they take things for granted, and the more they may be inspired to learn science in order to make the world a better place. Would they have those responses if continually told through school and media that everything just arrived by a chain of accidents?