G'day team,

Have you ever wondered how chameleons are able to change the color of their skin through every hue of the rainbow? Today we'll have a quick look at these amazing creature and begin to understand how they're able to create the amazing displays that they do.

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There are over 200 species of chameleon, ranging in adult body size from the tiny, measuring only 2cm in length, to the huge which can measure up to 70cm . Truly an animal with huge variability!

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The Smallest and the Largest

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While most species live in sub-Saharan Africa they can be found across Southern Europe, the Middle East and as far as Sri Lanka! The little devils surely get around!

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A Sri Lankan Chameleon

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So, let's talk about those colours! The chameleon's favourite trick has always been changing the colour of it's skin through green, red, blue and yellow. While early scientists always assumed this was a trick for camoflage recent research has indicated the real reason for these colourful displays are...

• Temperature modulation - darker colours help warm the chameleon, something they can't do by themseles as they're cold-blooded
• Communication - It's always easier to scare off a preditor or find a mate if you can pick the outfit that suits the occasion

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Unlike other creatures (octopus and frogs) which control the colour of their skin by regulating the abundance of pingments in skin cells, chameleons take a... layered approach.

The chameleon's skin has a number of layers, each of which contains cells that are different colours (called chromatophores). By controlling the expansion and contractionof these cells, the chameleon is able to regulate what colour it appears to be.

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So let's have a closer look. The chameleon's skin has the following layers...

• The outermost layer is clear and allows all coloured light through
• A layer which contains
• A layer of blue cells called iridophores containing a coloured crystals made of guianine
• A layer of red and yellow cells (erythrophores and xanthophores respectively)
• A bottom layer with a melanophores, which contain the same pigment as makes human skin brown

Cells in each of these layers are controlled by nerves or changes in blood. For example if the chameleon wants to appear red it expands it's erythrophores. If it wants to appear green it will contact them and partially expant xanthrophores letting them filter blue light from the iridophores below to create a green colour.

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So we finally know how chameleons are able to make such incredible displays. Now it's important to remember that colour changing isn't the only special feature of a chameleon! They also have an incredible tongue and eyes that allow them to see 360^o. But perhaps they're topics we'll discuss another day.

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Thanks

Thanks for reading team, I hope you had as much fun reading as I had writing

Interested in more amazing creatures? Read my past articles below!
Natures Best Mother - The Great Pacific Octopus
The Oldest Caterpillar

Thanks again!

-tfc

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Resources
Note all image sources down here to keep everything above looking pretty!
Image source 1
Image source 2: a and b
Image source 3
Image source 4
Image source 5
Image source 6
Image source 7
Image source 8

Information Resources
Wonderopolous
Wired
The Naked Scientist
Scientific Australia
The Dodo
Science ABC
Seeker
Live Science

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