Data from: A chorus of color: hierarchical and graded information content of rapid color change signals in chameleons

Animals rely on information-rich signals to minimize costs associated with competition. If fighting ability is linked to stable individual attributes (e.g. morphology), the signals that communicate information about such ability should be relatively static. Conversely, the temporal variability of motivation should favor dynamic threat signals that indicate an animal's likelihood of escalating a contest. Though static colors are used by many animals to signal quality or fighting ability, the function of dynamic color change as a social signal has only recently begun to be investigated. Here, we examined the information content of rapid physiological color changes displayed by adult male veiled chameleons Chamaeleo calyptratus during agonistic interactions by conducting experimental trials between live chameleons and standardized, experimentally-controlled robochameleon models. Chameleons reliably communicated motivation with dynamic color displays – individuals that brightened were 14 times more likely to approach the robochameleon than non-brightening individuals. Additionally, chameleons with shorter latencies to maximum stripe brightness had stronger bites, and those displaying brighter, yellower stripes exhibited more aggression. The parallels between dynamic color changes and the vocalizations used to mediate aggressive interactions in other taxa are numerous. The use of particular vocalizations/color changes can signal motivation levels while specific signal elements (e.g. pitch, timing, brightness) may be linked to fighting ability. Because the complexity and potential information content of color signals increases markedly when organisms can display context-specific variation in the expression of these ornaments, the study of dynamic color signals is a field ripe for the investigation of complex visual and signaling strategies.动物依赖富含信息的信号以降低竞争相关的代价。若争斗能力与个体稳定属性（如形态特征）相关联，则传递此类能力信息的信号应相对静态。与之相反，动机的时间变异性应偏好动态威胁信号——这类信号可表明动物升级争斗的可能性。尽管诸多动物会利用静态体色传递自身质量或争斗能力的信号，但体色动态变化作为社会信号的功能直至近年才开始得到研究。本研究通过开展活变色龙与经标准化实验操控的机器变色龙（robochameleon）模型间的对照实验，探究了成年雄性高冠变色龙（Chamaeleo calyptratus）在争斗互动过程中展现出的快速生理性体色变化所携带的信息内涵。研究结果表明，变色龙可通过动态体色展示可靠地传递动机状态：体色变亮的个体接近机器变色龙模型的概率是未体色变亮个体的14倍。此外，体色条纹亮度达到峰值的潜伏期更短的变色龙，其咬合力更强；而展现出更明亮、偏黄色条纹的个体则表现出更强的攻击性。动态体色变化与其他分类群中用于介导争斗互动的发声行为之间存在诸多相似之处：特定的发声或体色变化可传递动机水平，而特定的信号元素（如音调、时序、亮度）则可能与争斗能力相关联。当生物能够针对不同情境展现这类体表装饰结构的表达差异时，体色信号的复杂性与潜在信息含量会显著提升，因此动态体色信号的研究是探究复杂视觉与信号策略的成熟领域。