Chameleons are a top-tier freaky pet that you just can’t help but be mesmerized by
and their active color changing abilities are a picture perfect example of chemistry
going hand in hand with evolution.
Believe it or not, these oddball reptiles are actually working with a different chemical
toolbox than cephalopods and their other color-changing counterparts.
Today we’re looking how they work their magic, and how it’s inspired scientists
to invent up-and-coming technologies!
One thing that really stands out about chameleons is that they always have this suspiciously
chilled out look on their faces, but that’s not all when it comes to bizarre features.
Their feet are zygodactylous, with three toes facing forward and two going the opposite
direction.
They also have monocular vision, so their eyes can move about and focus independently
from each other!
If you’ve ever seen a chameleon eat, then you also know about their amazing projectile
tongues!
But the cream of the crop of their freaky features is going to have to be their psychedelic
skin.
Chameleons have the ability to actively change both their color and brightness.
While it’s often thought to be used for just camouflage, scientists believe that there
are two other fundamental uses, the first being intra-specific interspecies communication,
and the second being a means for thermoregulation.
Because chameleons are cold blooded, they need sunlight to heat themselves up to get
their metabolism running.
By controlling how bright or dark they are, they can better regulate how much heat they
take on.
And while their color changing may not seem to stand out from cephalopods and others,
they do have a chemical mechanism that sets them apart from the crowd.
Cephalopods and chameleons have color-changing cells called chromatophores that carry pigments
inside of them that can be displayed at will; however, there is a big difference between
the two.
The chameleon’s version comes equipped with an advanced layer of nano-science.
This colorful little guy is known as a Panther Chameleon, and its skin can exhibit a range
of these specific colors Here’s where it gets interesting: only /these/ specific colors
can be displayed by the typical pigments release by chromatophores.
So where do they get those whites, blues, and greens?
From unique cells called iridophores.
Iridophores aren’t filled with pigments but instead with tiny little structures of
nano-crystals that can produce iridescent blue light at their resting state.
The chameleon can excite these crystals, rearranging them into a different structure that changes
the wavelengths of light that they absorb and reflect.
This turns them from blue to white.
We’re not sure exactly how chameleons control their iridophores, but we suspect that they’re
working with either neural or hormonal controls.
And while some cephalopods are packing iridophores too, chameleons are the ones that have truly
mastered them.
Inside the panther chameleon’s skin are several layers of different colored chromatophores.
The top layer contains a mix of yellow xanthophores and red/orange erythrophores.
The bottom layer has brown, melanin-bearing melanophores.
Mixed into the top layer of red and yellow chromatophores are your iridescent light generating
iridophores, and in-between these two layers you find reflective iridophores.
The chameleon changes its skin color by adjusting the pigments released by their chromatophores,
and then takes things one step further by using those iridophores to change the way
the way we perceive the chromatophores pigments.
For example, the Panther Chameleon can produce a green color because those resting nanocrystals
reflect blue light, so pair that with the yellow pigment up above, and your eyes perceive
green.
Then when excited, the blue becomes white which will make the yellow xanthophores stand
out more prominently.
This use of nanocrystals is so ingenious that it even inspired scientists in China to come
up with their own active camouflage nanotechnology!
Instead of of iridophores, these researchers created tiny gold nanoparticle domes that
they housed in cells filled with a silver ion loaded gel.
By sending different charges through the gel, silver ions will tack onto, or break off of
the gold nano-domes which changes the wavelengths of light they absorb and reflect.
The team attached this system to cameras and can currently change the active color of the
cells to red, green, and blue.
So what do you think?
If this technology keeps advancing, will we ever see active camouflage as advanced as
the Predator’s?
Let us know down in the comments and while you’re at it if you want to learn more about
the chemistry in your favorite animal post it down there as well.
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