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What color do you think of when I say "flamingo"?
Pink, right?
Well, you’re wrong! Sort of.
Check out this baby flamingo. It’s very cute, and, as you can see, also very not pink.
It's gray.
There’s nothing wrong with it or anything; it's not sick.
It’s just that flamingos aren’t born with their familiar pink feathers.
So how and when do these birds get their rosy color?
Maybe you've already guessed that it has something to do with their diet.
But how exactly does the process work?
Flamingos feast mainly on algae, shrimp, clams, and other crustaceans and mollusks.
These organisms, particularly algae and shrimp, are high in reddish-orange pigments called carotenoids.
But the algae and shrimp themselves aren’t bright pink,
because the pigments start out as parts of other compounds, like astaxanthin.
That astaxanthin is bonded to a protein, which affects the way the pigments inside it absorb and reflect light.
Instead of reflecting the red part of the spectrum, which is what makes them look red, they reflect blue.
But all that changes once they get eaten by the flamingo.
When the birds digest their carotenoid-filled meals, their digestive enzymes detach the pigments from the proteins,
and once they’re free, the pigments start reflecting red light.
Then, they’re incorporated into fats that are deposited into the bird’s growing feathers.
After two to three years, the accumulating fats slowly turn the feathers into their iconic pretty-in-pink shade.
The same effect happens much more quickly when you boil lobster or shrimp.
The heat denatures, or changes the shape of, proteins attached to pigments in the animal's shell,
turning it from brown or gray to red or pink.
And the color change can happen in humans, too.
You probably don’t pick up a lot of algae at the grocery store,
but you likely do eat some foods that are high in carotenoids,
like carrots, apricots, squash, and mangoes.
If you eat too much of those foods, your skin can turn orange, a condition known as carotenosis.
But because we have varied diets and don’t just eat carrots all the time,
we don’t usually have to worry about our bodies changing color.
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