Chameleons are often portrayed differently from their actual nature. They change color primarily for reasons other than camouflage. While it is commonly believed that chameleons change color to blend into the background and escape danger, this is not the truth. So, what is the real reason behind the color change in chameleons?
How and Why Do Chameleons Change Color?
Due to their lack of defense mechanisms such as dangerous bites or poisonous skin, chameleons have limited means of defending themselves against predators. However, their ability to change color serves as a survival tactic. Interestingly, while chameleons can indeed blend into their environment without changing color, they primarily rely on color change for a different purpose.
When chameleons are calm, their natural colors are usually shades of brown, gray, or green, allowing them to seamlessly hide among leaves and trees in their natural habitat. Additionally, chameleons can adjust the brightness of their skin to match the ambient light outside. This adaptation doesn’t require them to display elaborate or vibrant colors. Subtle changes in hue are sufficient for their purposes.
The true reason behind the color change in chameleons extends beyond camouflage alone.
The color-changing abilities that have made chameleons popular have more to do with communication rather than protection from danger. Bright colors serve as a means for chameleons to express their emotions. Similar to mood rings, their skin color reflects how they feel. When a chameleon is angry or scared, it darkens its colors, whereas it brightens its colors when attempting to establish dominance.
For instance, male chameleons are highly territorial. When two males encounter each other, they engage in a color contest, with the competition continuing until one of them, typically the smaller or less dynamic one, surrenders. At this point, the defeated chameleon “turns off” its colored display, signaling to the dominant male that it has conceded. According to a study, some males even imitate females, which have less vibrant colors, to avoid competition with rivals during the mating season.
Color change plays a vital role during chameleon mating. Males court females by displaying bright colors to impress and attract them. In response, females also undergo a color change. Though their colors may be less vibrant, they are still sufficient to convey their message effectively.
How Does a Chameleon Change Color?
The remarkable color changes in chameleons are facilitated by unique cells in their skin. These cells, known as iridophores or iridophore cells, play a crucial role. A study revealed that chameleons possess two layers of iridescent cells in their skin. These iridophores contain guanine nanocrystals that vary in size, shape, and arrangement. Consequently, chameleons are capable of altering the structure of these specialized iridophore cells, thereby modifying the way the nanocrystals reflect specific wavelengths of light.
For instance, when a chameleon is in a relaxed state, the nanocrystals within the iridophore cells in its skin move closer together. This arrangement causes the chameleon’s skin to reflect shorter wavelength colors, such as blue. However, during moments of excitement or when one male attempts to dominate another, the nanocrystals in these cells move further apart. This altered configuration enables the chameleon’s skin to reflect longer wavelength colors, including yellow, orange, or red.
Scientists suggest that chameleons also change color for another purpose: to aid in regulating their body temperature. Chameleons, being ectotherms or “cold-blooded” animals, cannot generate their own body heat and instead rely on external sources such as sunlight to warm themselves. It is believed that chameleons adjust their coloration based on their body temperature. Dark colors tend to absorb more light and heat, so when chameleons are cold, they may appear darker in color. Conversely, when they are warm, they may adopt lighter hues.
While chameleons are often associated with their ability to blend into their surroundings, it is their remarkable and rapid color-changing ability that truly captivates us. This unique attribute sets them apart in the animal kingdom, and it is no wonder they spark our imagination. In this article, we explore the reasons behind the chameleon’s color changes.