Why Do Flamingos Stand on One Leg?

Spoiler alert: No one knows for sure! Learn a bit about how flamingos work, plus science's best hypotheses for why they often balance on one leg, in this episode of BrainStuff, based on this article: https://animals.howstuffworks.com/birds/flamingos-stand-on-one-leg.htm

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Episode Transcript

Speaker 1 (00:01):
Welcome to brain Stuff production of iHeart Radio. Hey brain Stuff,
Lauren vogal Bomb. Here in a large, shallow body of water,
hundreds of flamingos might congregate like an avian water ballet team,
all preening their pink feathers, resting in the sun, and
standing on one leg for hours at a time. Flamingos

(00:22):
even sleep that way. It's a puzzle to science why
exactly flamingos stand on one leg so regularly, but there
are lots of theories on the subject. It's an impressive
ability considering that flamingo's legs are longer than their bodies
and most of their weight is oriented horizontally. Humans are
oriented vertically, with almost all of our weight in line

(00:43):
with our center of gravity. It really should be easier
for humans to stand on one leg than four flamingos,
but most of us have trouble standing on one leg
for ten seconds blood alone four hours, like flamingos too.
Most large waiting birds have the ability to stand on
one leg, and flamingos are one of the biggest waiting
birds out there. They range from about fifty inches tall

(01:07):
that's about but they don't weigh much, just about five
to eight pounds that's two to three and a half kilos.
Combine their height with their coloring, and flamingos are one
of the most recognizable birds in the world. It's startling
to see a large group of pink, red or vermillion
birds standing one legged or otherwise in a shallow pond.

(01:28):
The color, of course, comes from the food that they eat,
including shrimp, which is full of carotenoid pigments, the same
thing that makes carrots orange. Flamingos are almost always in groups,
anywhere from a few birds to a few hundred or
even a few thousand, and they live on every continent
except Australia and at Arctica. They're very social, a sleeping
preening their feathers and eating together. To eat, flamingos fish

(01:53):
sort of. They stick their heads in the water upside
down and suck mud and water in through the front
of their beak. The up in the bottom of the
beak have bristles that intertwine when they meet, forming a
comb like filtering mechanism. The water and mud flow through,
getting pumped out of the sides of the beak. What's
left is the flamingos food, usually algae and small crustaceans.

(02:15):
They stand on both legs to eat, but on one
leg to sleep. It seems like sleeping would require both
legs on the ground for balance since the animal is unconscious.
So why do flamingos do it? Here are a few theories. Okay,
if you stood in the water all day, your skin
would prune up. Well, waiting birds have the same problem,

(02:35):
and this is where one of the theories comes from.
Maybe flamingos stand on one leg to dry their other off.
Since flamingoes alternate which foot they've got in the water,
this theory does seem possible, but it's not super popular.
Some experts think that the one leg balancing act might
have to do with the flamingos brain. Many animals, including
dolphins and ducks, only turn off one side of their

(02:57):
brain at a time when they sleep, and ducks, along
with herons, storks, and geese, have also been known to
stand on one leg for long periods of time. If
flamingoes keep half their brain awake while they sleep, that
could explain why they sleep on one leg. The leg
controlled by the side of the brain that's awake, stays
on the ground to maintain balance while the other leg
and foot get to rest up for a while. The

(03:21):
most common theories, though, relate to hunting and energy conservation.
The sense of flamingos legs are so long and make
up the majority of the bird's height, it takes a
lot of energy to pump blood through both legs. That's
a big strain on the heart. It's possible that pulling
up one leg to rest and tucking it up into
the body allows the heart to more easily pump blood

(03:42):
through the body, since only one leg is fully extended.
At the same time, this could conserve body heat. It's
like wrapping your arms around your torso to stay warm.
The more compact you make your body, the easier it
is to warm up. This is an imperfect theory, though,
since flamingoes will stand on leg in both cold and
hot weather. There are many scientists who think flamingos keep

(04:06):
just one leg in the water in order to better
camouflage themselves. A lagoon has lots of long, thin objects
in it, including reeds and small trees. A flamingo on
one leg could resemble a tree with a thin trunk,
especially when seen from inside the water, so a flamingoes
underwater prey might think that it's a safe place to swim.

(04:26):
This theory would make more sense, though, if the flamingos
prey were a bit more site driven. So nobody is
sure exactly why flamingoes do this, but there is an
interesting anatomical mechanism that may help explain how a flamingoes
ankle is where you would expect the knee to be
near the middle of the leg, the knee is so

(04:47):
far up in the leg that's usually hidden by the body,
and that ankle has something that a human ankle doesn't.
The joint actually snaps shut to literally lock it in place,
and some scientists think that this locking chanism may be
the key to a flamingo's incredible balancing act. Today's episode

(05:10):
is based on the article why does Flamingo stand on
one leg? On how stuff Works dot com written by
Julia Layton. Green Stuff is production of I Heart Radio
in partnership with how stuff Works dot Com, and it it
is produced by Tyler Clain. Four more podcasts. My Heart
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