Why A Chameleon Always Changes its Spots

Many of us mistakenly think that chameleons change their color to camouflage themselves against the predators they encounter in their daily lives. However, that isn’t why they cloak themselves in so many different, wonderful colors. Nor do they only change colors to match their surroundings. Surprisingly, the answer is much more complicated.

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Sadly, chameleons cannot change their skin to match *every* background they encounter in their daily lives. Chameleons, sadly, don’t have many defenses in the wild besides blending into their surroundings, even if they can’t automatically match every background. In their natural coloring, they often already resemble the detritus on ground or even a lot like leaves or branches. However, their real skill is the ability to change how bright their skin appears, Dr. Devi Stuart-Fox, an evolutionary biologist at the University of Melbourne told National Geographic, “It’s like putting a dark wash on everything,” Stuart-Fox says. “You’ve got to imagine paint mixing: If you have green paint and mix more black into it, it will change the brightness and also the hue.”

The bright colors and elaborate displays we so often think of when we think of chameleons have nothing to do with blending in and everything to do with standing out. In fact, these colors help guard their territory. When defending territory against another male, chameleons will become a wide array of colors - yellow, red, white...anything besides the color of the forest or trees. Instead of waving a white flag, the weaker male will admit defeat by returning to their more natural colorings.

In addition to defense, they also use it go on the offense, at least when it comes to dating. They will put on displays - rapidly changing colors and brightness - to show off to the females. Female chameleons will respond with their own display indicating their interest.

It has even ANOTHER use -- to regulate their body heat! Since chameleons aren’t able to generate body heat on their own, changing the color of the skin can be an important way to do this. A cold chameleon will usually become darker to absorb heat, whereas a chameleon that has had enough may turn pale (or, at least, paler).

But, how do they do it? Well, they have transparent skin. Not completely transparent, but at least the top layer is. Under this transparent first layer of skin are more layers of skin that contain special cells called chromatophores. Chromatophores at every level of skin are, essentially, sacs that are filled with different kinds of pigment. There are several different kinds of pigment, such a iridophores (which have blue pigment) and xanthophores (yellow pigments). When the chameleon experiences changes in temperature or mod, its nervous systems tells which chromatophores to rise to the surface by expanding or contracting. This is how a chameleon can produce a whole variety of colors and patterns.

So, now we've busted an old wives tale of sorts - chameleons aren't the hide-and-seek champions we once believed they were (luckily, Bigfoot is still winning that title) and that these creatures and the way they express themselves physically is much more complicated than we originally guessed!



This file is licensed under the Creative CommonsAttribution 2.0 Generic license and was created by Becker1999