How (And Why) Do Chameleons Change Color?

Chameleons don't change color to blend it -- they change to stand out. Learn how they create those colorful patterns in this episode of BrainStuff.

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Episode Transcript

Speaker 1 (00:01):
Welcome to brain Stuff production of I Heart Radio. Hey,
brain Stuff, I'm Lauren bog Obama. And Chameleons have built
a pretty solid reputation on two commonly held beliefs, that
they can stealthily blend into their surroundings and that they
are the ideal subjects for iconic eighties anthems. But it
turns out that one of those supposed facts isn't quite right.

(00:24):
In fact, everything you think you know about chameleons and
their color changing capabilities is probably backward. We spoke with
Daniel Flynn, marketing manager for the Conservation Society of California
at the Oakland Zoo. He said the color changing properties
of chameleons don't really help them blend in, but rather
their natural relaxed state is what helps them blend in.

(00:45):
The expression blending in like a chameleon isn't entirely accurate,
meaning these lizards don't change their appearance to fit in,
but rather to stand out. Scientists Long believes the chameleons
change their coloring similarly to the way to puss a
switch shades, which is by stretching and contracting a series
of special cells under their skin that contain pigments, thus

(01:07):
making the color more or less pronounced. But biologists and
physicists somewhat recently realized that something else entirely is going
on with chameleons. They have crystal like cells under their
skin that refract light. They're called aritophores, and these cells
go through structural changes to produce different effects. Flynn explained

(01:27):
that when anything agitates or exhilarates the chameleon, that's when
things get colorful. He said, when they get excited, feel threatened,
or want to display positively towards a mate or negatively
to arrival, the crystals separate or compress and give off
the appearance of different colors. In a twenty fifteen study
published in the journal Nature Communications, researchers with the University

(01:49):
of Geneva in Switzerland revealed that a ritophores act like
tiny mirrors that selectively reflect and absorb different colors. While
a lot of animals have color patterns, birds and fish,
for example, the cells that make their vibrant displays possible
typically absorb or reflect certain regions of the visible light spectrum.
Each cell has its specialty. Chameleon cells are different. Aritophores

(02:12):
can actually absorb or reflect any and all colors of
the spectrum. Flynn said some species change more colors than others.
For example, some will change shades lighter to darker, while
others change to more vibrant, bright colors. There are quite
a few species, so there's a lot of variants among
all of them. They can change all different types of colors,
even colors that aren't visible to the human eye. When

(02:34):
a chameleon's mood changes, its nervous system activates the cells
to contract or expand. When the animal is relaxed, the
cells stay close together and reflect short wavelengths like blue.
A rush of excitement pushes those cells further apart, enabling
each aritophor to reflect longer wavelengths like red, orange, and yellow.
But if the naturally relaxed cells reflect blue, y are

(02:58):
chilled out. Chameleons typically green like their surroundings. This has
to do with pigment sacks inside the aritophores, Flynn explained. Basically,
when a chameleon is relaxed, they're naturally visible is green
to help them camouflage with the green leaves and trees.
This is due to the natural yellow pigment combined with
a relaxed state of the crystal cells, which reflect blue light.

(03:19):
Blue plus yellow equals green. It may not be easy
being green, but it's necessary for the chameleon, which has
no real defenses, Blending in is its best bet against predators.
So if the color changes are due to special cells
under the skin, why are the effects external. The outermost
layer of the chameleon skin is actually transparent. Beneath that

(03:40):
outer layer lies several more layers containing a variety of
specialized skills, including the blue and white light reflecting aritophores.
What's really wild is if the chameleon needs a dramatic
quick change, like when it's trying to show off for
a potential mate, it can quickly shed its outer layers
of skin to expose the aritophores to direct sunlight in
a hurry. There's not a ton of research to support

(04:02):
it yet, but some scientists believe chameleons color changing abilities
also allow them to regulate their body temperature. A study
demonstrated the bearded dragons alter their hue based on their
body temperature, and since chameleons are ectotherms and can't retain
body heat, hence their stereotypical sunbathing. It's possible that maintaining
a dark color allows them to absorb more light and heat.

(04:28):
Today's episode was written by Michelle kumb Stantardowski and produced
by Tyler Clang. Brain Stuff is a production that I
Heart Radio's How Stuff Works. For more on this and
lots of other colorful topics, visit our home planet has
Stuff Works dot com, and for more podcasts for our
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