[PBS Bumper] [OPEN] There are no blue tigers. No blue bats, no blue squirrels, or blue dogs. Even blue whales aren’t that blue. Animals come in pretty much every color, but
blue seems to be the rarest. What’s cool, though, is when we do find
a blue animal, they’re awesome looking. Nature doesn’t do halfway with blue. To understand why this is, we’re gonna journey
through evolution, chemistry, and some very cool physics. But, first we’re gonna need to understand
why animals are any color at all, and to do that, we need to go look at some butterflies…
because butterflies are awesome… and if you don’t think so, you’re wrong This is Bob Robbins. He’s curator of Lepidoptera at the National
Museum of Natural History in Washington D.C. Butterflies ARE awesome. Make no mistake about it. They’re a group of moths that evolved to
be active during the day, and if you’re active during the day, you have an advantage:
You can use light to communicate. You probably realize this, but out of all insects, butterflies display the brightest and most detailed patterns. And there’s a good reason for that: The colors in butterfly wings deliver messages,
like “I’m toxic”, or “I’m a male and this is my territory”, but not all butterfly
colors are created equal. If we zoom way in on a butterfly wing, we
see the colors come from tiny scales. It’s actually how moths and butterflies
get their scientific name. Oranges, reds, yellows browns…those scales
all contain pigments, organic molecules that absorb every color except what we see. Black scales absorb all colors. Animals, from butterflies to birds to you
and me, don’t make these pigments from scratch, they’re made from ingredients in our diet. You might know this thanks to flamingos: They’re
born gray, but turn pink thanks to pigments called carotenoids in crustaceans they eat. So when it comes to these colors: You are
what you eat. But not so for blue. Blue is *different* If you move the camera, you can see that the
color changes as you move the camera. It does. It’s like a hologram thing. This is because there’s no blue pigment
in these butterflies Wait… so they’re blue, but they’re not
really blue? That’s correct! Yes. You’re lying to me butterflies! These are Blue Morpho butterflies, maybe the prettiest butterflies of all. I mean… they did make it the butterfly emoji. The blue color isn’t from a pigment. The blue comes from the shape of the wing
scale itself, and when I learned how this works, it kinda blew my mind. If we zoom way in on a blue wing scale, we
see these little ridges. If we slice across the scale, and look closer,
we see those ridges are shaped like tiny Christmas trees. The arrangement of the branches is what gives
Morpho wings their blue color. When light comes in, some bounces off the
top surface. But some light passes into the layer and reflects
off the bottom surface. For most colors of light, waves reflecting
from the top and bottom will be out of phase, they’ll be canceled out, and that light
is removed. But blue light has just the right wavelength:
the reflected light waves are in sync, and that color makes it to our eye. This hall of mirrors only lets blue light
escape. There’s even a pigment at the base that
absorbs stray red and green light to make the blue even more pure. That’s how we get this awesome iridescent
blue. The microscopic structure of the wing itself. All of this happens because of the way light
bends when it moves from air into another material. So if we fill all those tiny gaps with something
other than air, like alcohol, the blue disappears. Technically, this “changes the index of
refraction”, but in plain English that means blue light is no longer bent the right way. The microscopic light filter is broken. Until the alcohol evaporates. And the color returns. But these butterflies live in the rainforest. You think they’d lose their color any time
they got wet, right? Well watch this. These wing scales are made of a material that’s
naturally water-resistant. What about this blue jay feather? If we look through it, the color completely
disappears. No blue pigment. Each feather bristle contains light-scattering
microscopic beads, spaced so everything but blue light is canceled out. Unlike the highly-ordered structures we find
in butterfly wings, these feather structures are more messy, like a foam, so instead of
changing as we move, the color’s more even from every direction. Peacock tail feathers? Again it’s the shape of the feather, not
pigment. But the light reflecting structures here are
more ordered, like a crystal, so it’s brighter from certain angles. There’s even a monkey–WHOA let’s keep
this PG!!–even that color is made by the adding and subtracting of light waves thanks
to structures in the skin… not pigment. And yes, even your blue eyes, are colored
by structures, not pigments. Outside of the ocean, almost exclusively,
the bluest living things make their colors with microscopic structures, and each one’s
a little different. No vertebrate, not a single bird or mammal
or reptile that we know of, makes a blue pigment on its body. In fact, there’s only one known butterfly
that has cracked the code for making a true blue pigment. Blue as a pigment in nature is incredibly
rare. But there’s one exception so far that we
know about, and these are over here called the olivewings. They have evolved a blue pigment. They’re not very common and we don’t know
much about them, and I don’t know of any other blue pigment. That’s a really special butterfly. Why is almost all of nature’s blue made
from structures and not pigments like everything else? I’ve asked this question to several scientists
that study color, and here’s their best theory so far: At some point way back in time,
birds and butterflies evolved the ability to see blue light. But they hadn’t yet evolved a way to paint
their bodies that color. But if they could, it’d be like going from
early Beatles to Sgt. Pepper’s Beatles. it meant new opportunities for communicating
and survival. Creating some blue pigment–out of the blue–would
have required inventing new chemistry, and there was no way to just add that recipe to
their genes. It was much easier for evolution to change
the shape of their bodies, ever so slightly, at the most microscopic level, and create
blue using physics instead. They solved a biology problem with engineering. What I love about this is these colors have
fascinated curious people for hundreds of years. After looking at peacock feathers through
one of the first microscopes back in the 1600’s Robert Hooke wrote:
“these colours are onely fantastical ones” Even Isaac Newton noticed there was something
unusual about these blues, and scientists have been studying it ever since. Not only because the science is interesting,
but because it’s beautiful. Thanks for watching, and stay curious.

Why Is Blue So Rare In Nature?
Tagged on:                                                                                                                                         

100 thoughts on “Why Is Blue So Rare In Nature?

  • January 9, 2018 at 2:35 pm
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    You never notice how rare blue is, until you do, and then you (don't) see it *everywhere*.

    Leave a comment and let me know what you thought of this week's video! And commence the blue-pun party

    Reply
  • August 6, 2019 at 11:27 am
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    You see butterflies are awesome.but u put them in a board 😡😡😡

    Reply
  • August 6, 2019 at 11:43 am
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    I thought there's a blue dog😟😟

    Reply
  • August 6, 2019 at 1:46 pm
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    Purple is by far much rarer than blue. There are many blue flowers, butterflies, bugs, you name it. Blue is sometimes a warning signal for poison, so blue can be found in places warning poison. Blueberries, blue butterflies, blue flowers.

    Reply
  • August 6, 2019 at 1:54 pm
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    I sniff water

    Reply
  • August 6, 2019 at 1:54 pm
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    But……

    I’m BLUE da ba de da ba die!🤩

    Edit: like if u know what I am talking about

    Reply
  • August 6, 2019 at 2:18 pm
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    okay I think I'm colour blind, some parts of the ocean looked blue to me OOF

    Reply
  • August 6, 2019 at 3:50 pm
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    Thanks for the video!!
    Thanks for feeding our curiosity!!

    Reply
  • August 6, 2019 at 5:36 pm
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    Title of the video : why blue is so rare in the nature…

    Me : suddenly thinks of oceans, sky 😁

    Reply
  • August 6, 2019 at 10:00 pm
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    I a parrallell universe some butterfly scientist is playing with discected arms

    Reply
  • August 6, 2019 at 10:03 pm
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    Lol ocean blue

    Reply
  • August 6, 2019 at 11:45 pm
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    75% of the world is blue.

    Reply
  • August 7, 2019 at 1:20 am
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    Have you ever seen the ocean

    Reply
  • August 7, 2019 at 1:43 am
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    How about blue Betts AKA Siam Fighting fish?

    Reply
  • August 7, 2019 at 2:28 am
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    Is the earth rare then??

    Reply
  • August 7, 2019 at 4:38 am
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    ME: R E D

    Reply
  • August 7, 2019 at 1:17 pm
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    wait water is rare??

    Reply
  • August 7, 2019 at 2:55 pm
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    thanks…

    Reply
  • August 7, 2019 at 8:08 pm
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    Title: Why Is Blue So Rare in Nature
    Me: Looks at sky and water

    Reply
  • August 7, 2019 at 8:41 pm
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    There’s a blue snake, if U search “Blue Snake” on Google it will tell you the species.

    Reply
  • August 7, 2019 at 10:03 pm
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    Rarer then purple !?!

    Reply
  • August 8, 2019 at 1:06 am
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    What about chameleon

    Reply
  • August 8, 2019 at 1:32 am
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    So….butterflies are lying to us?

    Reply
  • August 8, 2019 at 1:59 am
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    I wish I was smart..

    Reply
  • August 8, 2019 at 3:33 am
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    IKEA bird:

    *evil anime man**ahhaahaha *BAKADAAA

    Reply
  • August 8, 2019 at 3:40 am
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    It is rare in skyrim too

    Reply
  • August 8, 2019 at 3:44 am
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    Ocean: am I a joke to you?

    Reply
  • August 8, 2019 at 6:20 am
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    Color Placer: Butterfly, which color do you want?

    Butterfly: Yes

    Reply
  • August 8, 2019 at 7:16 am
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    My favorite colour is blue

    Reply
  • August 8, 2019 at 7:42 am
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    I has a question, since white is all the colors absorbed then how does the black scales absorb all the colors if black is none of the colors in the color spectrum?

    And this is a really cool video! I just saw this scrolling down my recommendations and I’m really impressed and I really love science

    Reply
  • August 8, 2019 at 10:48 am
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    blue is my fav color

    Reply
  • August 8, 2019 at 12:05 pm
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    BeCaUsE iTs DiAmOnD cOlOr

    Reply
  • August 8, 2019 at 6:25 pm
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    The Sky: Am I a joke to you?
    It's ok to be Smart: Yes.
    The Sky: Sad wind noises
    Clouds: Excuse me wtf

    Reply
  • August 8, 2019 at 9:52 pm
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    Oceans and seas and lakes: AMMM II A FREAKKKINNNG JOKKKKE TO YOUUUUUUU!

    Reply
  • August 9, 2019 at 2:37 am
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    Look at the sky.

    Reply
  • August 9, 2019 at 4:04 am
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    🦋🦋🦋🦋🦋🦋🦋🦋🦋🦋🦋🦋🦋🦋🦋🦋🦋🦋🦋🦋🦋🦋🦋🦋🦋🦋🦋🦋🦋🦋🦋🦋🦋🦋🦋🦋🦋🦋🦋🦋🦋🦋🦋🦋🦋🦋🦋🦋🦋🦋

    Reply
  • August 9, 2019 at 4:09 am
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    2/3 is blue on this planet, very rare

    Reply
  • August 9, 2019 at 6:11 am
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    Blue is rare

    hi ocean

    Reply
  • August 9, 2019 at 6:54 am
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    Only if these stupid people know that the sky and water is blue

    Reply
  • August 9, 2019 at 9:37 am
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    LOOK AT THE SKY

    Reply
  • August 9, 2019 at 11:32 am
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    Me: are you Blue?
    Butterfly: well yes, But actually no.

    Reply
  • August 9, 2019 at 11:32 am
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    I'm blue ladaelsialsosdlks

    Reply
  • August 9, 2019 at 11:47 am
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    Yo, listen up here's a story
    About a little guy
    That lives in a blue world
    And all day and all night
    And everything he sees is just blue
    Like him inside and outside

    Blue his house
    With a blue little window
    And a blue corvette
    And everything is blue for him
    And himself and everybody around
    Cause he ain't got nobody to listen to

    I'm blue
    Da ba dee da ba di
    Da ba dee da ba di
    Da ba dee da ba di
    Da ba dee da ba di
    Da ba dee da ba di
    Da ba dee da ba di
    Da ba dee da ba di
    I'm blue
    Da ba dee da ba di
    Da ba dee da ba di
    Da ba dee da ba di
    Da ba dee da ba di
    Da ba dee da ba di
    Da ba dee da ba di
    Da ba dee da ba di

    I have a blue house
    With a blue window
    Blue is the colour of all that I wear
    Blue are the streets
    And all the trees are too
    I have a girlfriend and she is so blue

    Blue are the people here
    That walk around
    Blue like my corvette its in and outside
    Blue are the words I say
    And what I think
    Blue are the feelings
    That live inside me

    I'm blue
    Da ba dee da ba di
    Da ba dee da ba di
    Da ba dee da ba di
    Da ba dee da ba di
    Da ba dee da ba di
    Da ba dee da ba di
    Da ba dee da ba di
    I'm blue
    Da ba dee da ba di
    Da ba dee da ba di
    Da ba dee da ba di
    Da ba dee da ba di
    Da ba dee da ba di
    Da ba dee da ba di
    Da ba dee da ba di

    I have a blue house
    With a blue window
    Blue is the colour of all that I wear
    Blue are the streets
    And all the trees are too
    I have a girlfriend and she is so blue

    Blue are the people here
    That walk around
    Blue like my corvette, its in and outside
    Blue are the words I say
    And what I think
    Blue are the feelings
    That live inside me

    I'm blue
    Da ba dee da ba di
    Da ba dee da ba di
    Da ba dee da ba di
    Da ba dee da ba di
    Da ba dee da ba di
    Da ba dee da ba di
    Da ba dee da ba di
    I'm blue
    Da ba dee da ba di
    Da ba dee da ba di
    Da ba dee da ba di
    Da ba dee da ba di
    Da ba dee da ba di
    Da ba dee da ba di
    Da ba dee da ba di

    Reply
  • August 9, 2019 at 12:15 pm
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    blue is rare in nature!!!
    Sea water-hold my waters

    Sky-dont ever forget me!

    Reply
  • August 9, 2019 at 12:18 pm
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    Hmm let me think blue animals

    Blue whale
    Fish
    Berrys(nature remember)
    Ur mama
    And thata all i can think of

    Reply
  • August 9, 2019 at 12:39 pm
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    What about the ocean

    Reply
  • August 9, 2019 at 1:12 pm
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    Because it’s made of the sky

    Reply
  • August 9, 2019 at 1:43 pm
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    🦋

    Reply
  • August 9, 2019 at 4:58 pm
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    *looks at the sky*

    Reply
  • August 9, 2019 at 5:55 pm
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    You dif not answer your question your self

    The answer is
    It because 80% of our planet is blue "water ,sky"
    God decided not to overuse blue that is why he did not use it on animals

    Reply
  • August 9, 2019 at 6:30 pm
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    Even my comment is blue

    Reply
  • August 9, 2019 at 7:11 pm
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    Purple next?

    Reply
  • August 9, 2019 at 8:50 pm
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    The sky is blue

    Reply
  • August 10, 2019 at 4:28 am
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    Purple is rarer

    Reply
  • August 10, 2019 at 5:54 am
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    Name blue fishes
    Swordfish
    Neon Tetras
    Cardinal tetras
    Guppies
    Bettas
    Blue shark
    Powder blue tang
    Palette surgeonfish

    Reply
  • August 10, 2019 at 7:26 am
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    If our eyes are actually blue, and brown is a pigment that creates other eye colors such as green, light brown, dark brown, etc. And now you are saying that blue in our eyes is not a pigment but a light color…..Jeez we have zombie eyes lol

    Reply
  • August 10, 2019 at 7:47 am
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    I mean…

    It’s in the sky.

    Reply
  • August 10, 2019 at 8:36 am
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    Video – why blue is rare
    Me – has 100 blue color pencils

    Reply
  • August 10, 2019 at 10:46 am
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    The sky is blue. And it counts as nature so technically it's not so rare

    Reply
  • August 10, 2019 at 1:18 pm
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    Soooooo what you’re saying is…… blue in nature is similar to how the sky is blue?

    Reply
  • August 10, 2019 at 1:29 pm
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    Thats why i love blue and light blue

    Reply
  • August 10, 2019 at 2:15 pm
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    I’m scared of butterflies.

    Reply
  • August 10, 2019 at 4:21 pm
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    blue? rare? just look up in the day dumba$$es

    Reply
  • August 10, 2019 at 4:27 pm
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    Our earth is composed of 3/4 water and it's blue and the sky is blue also

    Reply
  • August 10, 2019 at 4:39 pm
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    Now my favorite color is blue 🦋

    Reply
  • August 10, 2019 at 5:22 pm
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    I love RaRe things that's why I love blue♥

    Reply
  • August 10, 2019 at 5:55 pm
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    im bluuu… da ba deeee.. da ba diieee

    Reply
  • August 10, 2019 at 6:42 pm
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    https://www.youtube.com/watch?v=68ugkg9RePc

    Reply
  • August 10, 2019 at 9:25 pm
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    This guy: Why is blue so rare in the wild
    Me:have you ever gone outside during the day?

    Reply
  • August 10, 2019 at 9:53 pm
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    everybody
    B ut tHe skY!

    Read the description.

    Reply
  • August 10, 2019 at 10:09 pm
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    exist Fishes .

    Reply
  • August 10, 2019 at 10:27 pm
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    Blue is rare in nature.
    Me: eating blueberries while watching this.

    Reply
  • August 10, 2019 at 11:26 pm
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    I wish I could go back to school and tell my Teacher she is wrong lol

    Reply
  • August 11, 2019 at 5:55 am
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    Me:sees blue bird
    Also me:MORDECAIII

    Reply
  • August 11, 2019 at 6:27 am
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    Alien : I'm blue dabedidabedai

    Reply
  • August 11, 2019 at 7:02 am
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    The sky and sea are blue

    Reply
  • August 11, 2019 at 9:21 am
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    blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue blue

    Reply
  • August 11, 2019 at 9:23 am
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    2:05
    Excuse you, Mr. Papa Smurf says otherwise.

    Reply
  • August 11, 2019 at 9:39 am
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    What about the ocean?

    Reply
  • August 11, 2019 at 12:18 pm
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    Blue OS not rare in nature just look at the water

    Reply
  • August 11, 2019 at 1:41 pm
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    What about purple?

    Reply
  • August 11, 2019 at 2:02 pm
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    The title should be:
    Why is blue pigment so rare in animals/ the animal kingdom.

    Reply
  • August 11, 2019 at 3:26 pm
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    What about purple??

    Reply
  • August 11, 2019 at 3:39 pm
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    Just yesterday i was trying to make the rainbow with fruits and vegetables.. this video is perfect

    Reply
  • August 11, 2019 at 5:33 pm
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    So…blue doesn't exist?

    Reply
  • August 11, 2019 at 6:34 pm
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    wth the sky bro

    Reply
  • August 12, 2019 at 6:18 am
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    Hmm is that why smurfs are blue?

    Reply
  • August 12, 2019 at 7:11 am
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    0:15
    Purple: Am I a joke to you?

    Reply
  • August 12, 2019 at 7:37 am
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    Title : Why Blue is So RARE!??

    WATER : Am I a joke to YoU 😑

    Reply
  • August 12, 2019 at 7:40 am
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    The sky – AM I A JOKE TO YOU???

    Reply
  • August 12, 2019 at 11:38 am
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    No, It's because it's my favorite color

    Reply
  • August 12, 2019 at 11:46 am
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    I once saw a butterfly with a mix of red and blue and its so beautiful!

    Reply
  • August 12, 2019 at 7:26 pm
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    There are no blue tigers. Somewhere in North Korea, a Maltese Tiger laughs horribly

    Reply
  • August 12, 2019 at 8:22 pm
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    Me: are you blue?
    Butterfly: well yes but actually no

    Reply
  • August 13, 2019 at 12:06 am
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    🤷‍♂️

    Reply
  • August 13, 2019 at 8:21 am
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    Blue is a color of vast emptiness like ocean and sky hahahaha idk what am saying scrolldown

    Reply
  • August 13, 2019 at 9:57 am
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    I wish I had blue eyes

    Reply

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