TEMPE, Ariz. To protect themselves, some animals rapidly change color when their environments change, but chameleons change colors in unusual ways when they interact with other chameleons. Arizona State University researchers have discovered that these color changes don't happen "out-of-the-blue" instead, they convey different types of information during important social interactions.
For example, when male chameleons challenge each other for territory or a female, their coloring becomes brighter and much more intense. Males that display brighter stripes when they are aggressive are more likely to approach their opponent, and those that achieve brighter head colors are more likely to win fights. Also, how quickly their heads change color is an important predictor of which chameleon will win a skirmish.
The results of the study are published online today in the journal Biology Letters.
Russell Ligon, a doctoral candidate in ASU's School of Life Sciences, and Kevin McGraw, an associate professor in the school, used photographic and mathematical modeling tools in new ways to study how the color change of veiled chameleons (Chameleon calyptratus) relates to aggressive behavior. They studied the distance, maximum brightness and speed of color change of 28 different patches across the chameleons' bodies.
"We found that the stripes, which are most apparent when chameleons display their bodies laterally to their opponents, predict the likelihood that a chameleon will follow up with an actual approach," said Ligon. "In addition, head coloration specifically brightness and speed of color change predicted which was lizard was going to win."
Chameleons typically have resting colors that range from brown to green, with hints of yellow, but each chameleon has unique markings. During a contest, the lizards show bright yellows, oranges, greens and turquoises. Interestingly, when the chameleons showed-off their st
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Arizona State University