Why Do Chameleons Change Color?
Crypsis, or camouflage, is the most common evolutionary hypothesis for why animals have the ability to change color. The other hypothesis is that it is used as a sort of social communication, much like body language. For Chameleons, the second hypothesis applies. In the article, 'Selection for Social Signalling Drives the Evolution of Chameleon Color Change' by Devi Stuart-Fox and Adnan Moussalli they explore what drove this evolutionary change.
In their review, the main focus of the study was the southern African dwarf chameleon, or Bradypodion. They studied these dwarf chameleons against different vegetation backgrounds. They looked for the most extreme color changes in the chameleons based on different situations, such as the presence of a predator or a social interaction. They found that the highest color changes occurred in social interactions where chameleon's tried to show dominance. Their research has shown that Chameleon's chromatin range and most dramatic color changes happens during social interactions. They're ability to change color is downplayed when in the presence of a predator. However, they're ability to change brightness is directly correlated with the presence of a predator. The Chameleon's rely more on the ability to change the brightness of their colors as camouflage. This lead to the conclusion that chromatic color change is most prevalent in social interactions. This means that chameleons primarily evolved the ability to change color to stick out to each another—and not to blend in. Thus holding the second hypothesis to be true! However, the Chameleons ability to change color includes a few separate functions, such as...
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