All chameleons can change color, although some are more variegated than others. Contrary to popular belief, chameleons do not change color to blend in with their surroundings, but rather change color based on their mood or to appear more threatening when something has entered their territory. Other animals, like the squid, have the same abilities, but they must gradually accumulate different pigments which they then release into the rest of their bodies. On the other hand, chameleons actually change the structure of their skin to reflect different wavelengths and are able to do so as often as possible.
On their outermost surface, chameleons have two layers of iridophore cells, special cells that retain pigment and reflect light. The structural arrangement of the cells changes when the chameleon is either excited or relaxed; thus, it changes color based on its state. When the skin is relaxed, the crystals within the cells are closer together, reflecting short wavelengths. This would mean that the chameleon would be blue, but most lizard skin has yellow pigments by default. Subsequently, these colors mix together to make a relaxed chameleon green and therefore naturally camouflaged. When the skin is excited, the cells spread farther apart, longer wavelengths are reflected, and the chameleon appears to be an orangish-red in stressful situations.
Photo by Tambako the Jaguar 
Dear Anna,
I am feeling very fascinated by Chameleons. I didn’t know that Chameleons did such things as to change to any color. I wonder if they change color by the environment or by temperature. I also didn’t know that they changed color based on their mood. Thanks for your writing and I look forward to seeing more Articles like this one. I want to see more articles like these because I like to know new things. Also, because it explained really interesting facts and I would like to know more things.
Dear Anna, That is very interesting, i had never known this. I think it’s interesting that they actually change the structure of their skin. I always thought they change color by their surrounding.
This is super cool! I always thought that chameleons changed depending upon their surroundings. I think it’s interesting that they actually change the structure of their skin.
I didn’t know this at all! I have always been interested by Chameleons, but I never knew why or how they changed colors. This really changed my views of Chameleons. Also, I feel like you got your opinion across very well and attract the readers.
This is so interesting! I had never known this, and you have written this very well. This could have been difficult to understand but you presented your thoughts in a clear, easy to understand way. Thanks for answering this question!
Wow! I had no clue about the workings of chameloans. It is so interesting that they can change their cell size and the wavelength with which they receive them. This was very clearly written and put the scientific terms in easy to understand words. Nice job.