Chameleons Changing Color. The How And Why Of It.

Here’s an easy to understand guide to how and why your chameleon changes color. Some chameleons even glow in the dark!

Glowing Chameleon

From Paul Bertner’s UV series: https://rainforests.smugmug.com/keyword/UV/

HOW CHAMELEONS CHANGE COLOR

It wasn’t fully understood exactly how chameleons changed color until 2014, when a study published in the journal Nature Communications explained the true science:

Many chameleons, and panther chameleons in particular, have the remarkable ability to exhibit complex and rapid colour changes during social interactions such as male contests or courtship. It is generally interpreted that these changes are due to dispersion/aggression of pigment-containing organelles within dermal chromatophores. Here, combining microscopy, photometric videography and photonic band-gap modelling, we show that chameleons shift colour through active tuning of a lattice of guanine nanocrystals within a superficial thick layer of dermal iridophores. In addition, we show that a deeper population of iridophores with larger crystals reflects a substantial proportion of sunlight especially in the near-infrared range. The organization of iridophores into two superposed layers constitutes an evolutionary novelty for chameleons, which allows some species to combine efficient camouflage with spectacular display, while potentially providing passive thermal protection.

 

Okay, so what the heck does that mean!? It means that the chameleon, or at least its nervous system, is actively involved in changing its own skin color by expanding and contracting cells in the skin which contain magic crystals. Depending on how these crystals are arranged, they will reflect different colors. You know that funny feeling you get when you see your crush? Maybe your heart flutters, or you get a little sweaty and nervous….If you had as many Chromatophores as a chameleon, every time you saw your crush you’d turn yellow or red or purple or blue, making it painfully obvious that you wanna get freaky. Likewise, if you saw a bully or someone you didn’t like, maybe you’d turn orange or pink….which may or may not help with the bullying…When you’re vegging out on the couch or computer, maybe you’d be brown or even black. The magic crystals are like millions of microscopic prisms, and as the shape of the prism changes the color light reflected changes – like customizable prisms.pink-floyd-rainbow-prism-dark-side-of-the-moon-wallpaper

This is a detailed diagram of what those cells look like in another creature that changes color – octopus:

Chameleons Changing Color colourMelanophores_with_dispersed_or_aggregated_melanosomes

Panther and Carpet chameleons are the most sophisticated of chameleons changing color species, as most of the 180+ species simply turn from green to brown, or varying shades of. In

Click me! I'm a GIF!

Click me! I’m a GIF!

all chameleons, cell signaling is responsible for expanding and contracting the muscle fibers which affect the concentration of the pigment – this can be triggered by mood, mates, rivals, temperature, hormones, and light exposure. The nervous system reacts accordingly to each situation just like you get sweaty palms or an adrenaline rush in a sticky situation. As the cell rearranges the magic crystals, the colors change. Kind of like how food coloring is so concentrated in a single drop, but as it spreads out it changes dramatically….like this! ——>

chameleon colors

The cell expands and contracts when the nervous system gets a signal from the eye/brain connection – the eye sees a potential threat or mate, and the nervous system reacts out of instinct. The cell can also get signals from temperature and light, changing automatically (just like how when you go in the sun, your cells produce Melanin, which is dark pigmentation causing your skin to become darker). These reaction affects how much visible light is absorbed and/or reflected into the crystals of each cell whether the chameleons changing color because he’s excited or relaxed. When your chameleon is injured by a cricket bite, or rubbing against a branch or something sharp, there will be a brown or black spot there because the cells in the skin were damaged and lost their ability to control these crystals. Here is microscopic imaging of the cell in both states, and the color spectrum associated with mood:

photonic crystals

 

Right, so what does this actually look like on a larger scale (pun intended). Here’s the most comprehensive video about chameleons changing color:

 

Now that’s covered…..why do they change color? Why do some glow under fluorescent light? Why do some reflect infrared light?

There are over 180 species of chameleons, and they all might have their own reasons. One study in 1981 showed that some species reflect infrared light, a very rare phenomenon in some amphibians but not previously observed in reptiles. The Brookesia superciliaris in the first photo of this article is glowing under UV light. We know that chameleons have sophisticated eyes which can see Ultraviolet Light – the leading theory is that since these chameleons look exactly like leaves, the UV light is how they can see each other among the leaf litter. To the Brookesia, another Brookesia would shine like a beacon instead of blend in like a dead leaf.

We can’t even imagine what a chameleon looks like to another chameleon – their skin reflects colors that we simply can’t see. Birds and insects can also see in the ultraviolet spectrum, and they look much different to each other than they do to us:

bird eye

Scorpions also glow under UV light, and scientists believe this is merely an accident. The truth is, scorpions are the oldest living vertebrates on the planet – they’ve been around for over 400 million years! Although experts can’t figure out why UV reflection is observed in scorpions, it’s highly likely that over the ages of the earth, there was a purpose – maybe to attract mates, or warn predators, or to lure some kind of now-extinct prey. The same can be said of chameleons, as they’ve been around for quite some time too..

Scorpions_glowing

Earlier this year, amber was discovered with a 100 Million Year Old chameleon preserved within. This beats the previous known record of chameleon fossil by over 78-Million Years! This means that, like other color-changing and UV sensitive creatures such as octopus, birds and insects, chameleons are ancient and have had some serious leisure time to manipulate and master the colors of light to their will.

world's oldest chameleon in amber

The fundamental reason why chameleons change color is efficiency. Everything about a chameleon has evolved to be efficient over those 100 million years. They can sit in one spot and see in all directions without having to move their head – they can catch prey 3x their body length with their tongue, without having to jump or climb – they can grip branches with their zygodactylous feet, and even if they lose their grip, they can still hang on with their prehensile tail so they don’t fall to the ground and have to climb back up. Chameleons are lazy.

Chameleons changing color is just another efficiency. They can communicate and see each other much easier from a distance by changing color. They can attract a mate, or show off to a rival, or claim their territory, or scare a predator, without having to move a muscle.

Also, sorry not sorry…this video with over 9,000,000 views about a veiled chameleon changing color is not real, but you can see how the myth spreads!

 

 

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