By Dr. Becker
If you’ve ever tried to balance on one leg for more than a few seconds, you know that doing so takes careful concentration and coordination. Even then, you’ll probably tire out quickly. The opposite holds true among flamingos, who spend much of their time standing on one leg only. In fact, it seems to be their preferred choice of stance — their go-to position when resting, grooming or even sleeping.
Why flamingos stand on one leg is open for debate, as multiple theories exist. It’s been suggested that standing on one leg may reduce muscle fatigue or make it easier to escape predators, but at least once study found these theories to be unlikely. Instead, the researchers found that flamingos seem to prefer resting on one leg instead of two in virtually all locations, but that the percentage of birds resting on one leg was much higher among birds standing in water than among those on land.1
Since birds tend to lose body heat quickly through their legs and feet, and even more so when standing in water, they suggested that standing on one leg may be a form of thermoregulation. They even found that flamingos tended to stand on one leg less often when temperatures rose, suggesting it may be a key way these birds maintain their body heat.
On the other hand, that may not be it at all. Recent research highlighted yet another reason why these striking birds may prefer standing on one leg instead of two, and it has to do with energy and what the researchers described as a “passive gravitational stay mechanism.”2
Flamingos May Stand on One Leg to Save Energy
U.S. researchers conducted experiments on live and dead flamingos, which revealed some surprising results: dead flamingos could still stand perfectly balanced on one leg, but not on two, without any support or muscle activity.3 This suggests the former requires very little, if any, muscular activity and much less so than standing on two legs.
The deceased flamingos were able to stand on one leg “adopting a stable, unchanging, joint posture resembling that seen in live flamingos,” the researchers noted, which suggests that flamingos engage in a “passively engaged gravitational stay apparatus” to support their weight. Professor Young-Hui Chang, Ph.D., from the Georgia Institute of Technology (Georgia Tech) in Atlanta, told BBC News:4
"If you look at the bird from the front, while they're standing on one leg, the foot is directly beneath the body which means that their leg is angled inward. That's the pose you have to strike in order to engage the stay mechanism … If you tilt it to the vertical, like you would if you were standing on two legs, the whole thing disengages.”
The birds do not have locking joints, but rather joints that are fixed in one direction but not the other. Further, the researchers discovered that when flamingos stand on one leg, they sway much less while resting or sleeping than they do while they’re alert, which once again supports the notion that flamingos are able to stand on one leg with very little, if any, conscious effort involved.
“Taken together, our results highlight the possibility that flamingos stand for long durations on one leg without exacting high muscular forces and, thus, with little energetic expenditure,” the researchers concluded.5
How Do Flamingos Eat Upside Down? Parent?
Flamingos are known for their bright pink feathers, which comes from the carotenoids in their favorite foods, including algae and crustaceans. However, aside from their pink hue and their penchant for standing on one leg, many people do not know much about these fascinating birds. For instance, they eat basically upside down, by ducking their beaks down into shallow water and filtering mud and water through but trapping shrimp, algae, fish and more.
How they’re able to do this is another mystery, but one study revealed they have erectile tissue in their mouths, which fills with blood when needed to strengthen the mouth and tongue, then goes away when it’s not needed.6 As for raising young, both male and female flamingos care for their nest and chick.
Recent research revealed, however, that males spent more time on the nest than did females and were more aggressive toward other flamingos when near the nest. “Therefore, male flamingos seem to be more involved in incubation duties and nest protection than females,” the study found.7 It’s also been shown that variations in plumage appear to influence flamingos’ choices in primary social partners (flamingos are monogamous), with redder males more likely to have primary social partners than less red males.
Primary social partners also tended to have similar colors to each other.8 These social creatures may live in flocks numbering in the thousands and may live to be 50 years old (although 20 or 30 is more typical).9 If you’d like to see flamingos in the wild, they live in South America, Africa and the Middle East, as well as the Caribbean. After an absence of 100 years, they’ve also recently been spotted returning to the Florida everglades.10