WEBVTT - How (And Why) Do Chameleons Change Color?

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<v Speaker 1>Welcome to brain Stuff production of I Heart Radio. Hey,

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<v Speaker 1>brain Stuff, I'm Lauren bog Obama. And Chameleons have built

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<v Speaker 1>a pretty solid reputation on two commonly held beliefs, that

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<v Speaker 1>they can stealthily blend into their surroundings and that they

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<v Speaker 1>are the ideal subjects for iconic eighties anthems. But it

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<v Speaker 1>turns out that one of those supposed facts isn't quite right.

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<v Speaker 1>In fact, everything you think you know about chameleons and

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<v Speaker 1>their color changing capabilities is probably backward. We spoke with

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<v Speaker 1>Daniel Flynn, marketing manager for the Conservation Society of California

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<v Speaker 1>at the Oakland Zoo. He said the color changing properties

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<v Speaker 1>of chameleons don't really help them blend in, but rather

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<v Speaker 1>their natural relaxed state is what helps them blend in.

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<v Speaker 1>The expression blending in like a chameleon isn't entirely accurate,

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<v Speaker 1>meaning these lizards don't change their appearance to fit in,

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<v Speaker 1>but rather to stand out. Scientists Long believes the chameleons

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<v Speaker 1>change their coloring similarly to the way to puss a

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<v Speaker 1>switch shades, which is by stretching and contracting a series

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<v Speaker 1>of special cells under their skin that contain pigments, thus

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<v Speaker 1>making the color more or less pronounced. But biologists and

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<v Speaker 1>physicists somewhat recently realized that something else entirely is going

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<v Speaker 1>on with chameleons. They have crystal like cells under their

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<v Speaker 1>skin that refract light. They're called aritophores, and these cells

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<v Speaker 1>go through structural changes to produce different effects. Flynn explained

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<v Speaker 1>that when anything agitates or exhilarates the chameleon, that's when

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<v Speaker 1>things get colorful. He said, when they get excited, feel threatened,

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<v Speaker 1>or want to display positively towards a mate or negatively

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<v Speaker 1>to arrival, the crystals separate or compress and give off

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<v Speaker 1>the appearance of different colors. In a twenty fifteen study

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<v Speaker 1>published in the journal Nature Communications, researchers with the University

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<v Speaker 1>of Geneva in Switzerland revealed that a ritophores act like

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<v Speaker 1>tiny mirrors that selectively reflect and absorb different colors. While

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<v Speaker 1>a lot of animals have color patterns, birds and fish,

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<v Speaker 1>for example, the cells that make their vibrant displays possible

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<v Speaker 1>typically absorb or reflect certain regions of the visible light spectrum.

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<v Speaker 1>Each cell has its specialty. Chameleon cells are different. Aritophores

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<v Speaker 1>can actually absorb or reflect any and all colors of

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<v Speaker 1>the spectrum. Flynn said some species change more colors than others.

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<v Speaker 1>For example, some will change shades lighter to darker, while

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<v Speaker 1>others change to more vibrant, bright colors. There are quite

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<v Speaker 1>a few species, so there's a lot of variants among

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<v Speaker 1>all of them. They can change all different types of colors,

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<v Speaker 1>even colors that aren't visible to the human eye. When

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<v Speaker 1>a chameleon's mood changes, its nervous system activates the cells

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<v Speaker 1>to contract or expand. When the animal is relaxed, the

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<v Speaker 1>cells stay close together and reflect short wavelengths like blue.

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<v Speaker 1>A rush of excitement pushes those cells further apart, enabling

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<v Speaker 1>each aritophor to reflect longer wavelengths like red, orange, and yellow.

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<v Speaker 1>But if the naturally relaxed cells reflect blue, y are

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<v Speaker 1>chilled out. Chameleons typically green like their surroundings. This has

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<v Speaker 1>to do with pigment sacks inside the aritophores, Flynn explained. Basically,

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<v Speaker 1>when a chameleon is relaxed, they're naturally visible is green

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<v Speaker 1>to help them camouflage with the green leaves and trees.

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<v Speaker 1>This is due to the natural yellow pigment combined with

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<v Speaker 1>a relaxed state of the crystal cells, which reflect blue light.

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<v Speaker 1>Blue plus yellow equals green. It may not be easy

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<v Speaker 1>being green, but it's necessary for the chameleon, which has

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<v Speaker 1>no real defenses, Blending in is its best bet against predators.

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<v Speaker 1>So if the color changes are due to special cells

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<v Speaker 1>under the skin, why are the effects external. The outermost

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<v Speaker 1>layer of the chameleon skin is actually transparent. Beneath that

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<v Speaker 1>outer layer lies several more layers containing a variety of

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<v Speaker 1>specialized skills, including the blue and white light reflecting aritophores.

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<v Speaker 1>What's really wild is if the chameleon needs a dramatic

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<v Speaker 1>quick change, like when it's trying to show off for

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<v Speaker 1>a potential mate, it can quickly shed its outer layers

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<v Speaker 1>of skin to expose the aritophores to direct sunlight in

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<v Speaker 1>a hurry. There's not a ton of research to support

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<v Speaker 1>it yet, but some scientists believe chameleons color changing abilities

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<v Speaker 1>also allow them to regulate their body temperature. A study

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<v Speaker 1>demonstrated the bearded dragons alter their hue based on their

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<v Speaker 1>body temperature, and since chameleons are ectotherms and can't retain

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<v Speaker 1>body heat, hence their stereotypical sunbathing. It's possible that maintaining

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<v Speaker 1>a dark color allows them to absorb more light and heat.

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<v Speaker 1>Today's episode was written by Michelle kumb Stantardowski and produced

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<v Speaker 1>by Tyler Clang. Brain Stuff is a production that I

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<v Speaker 1>Heart Radio's How Stuff Works. For more on this and

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<v Speaker 1>lots of other colorful topics, visit our home planet has

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<v Speaker 1>Stuff Works dot com, and for more podcasts for our

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