Rapid Body Color Change Provides Lizards with Facultative Crypsis in the Eyes of Their Avian Predators.

AbstractColor change serves many antipredator functions and may allow animals to better match environments or disrupt outlines to prevent detection. Rapid color change could potentially provide camouflage to animals that frequently move among microhabitats. Determining the adaptiveness of whole-animal rapid color changes in natural habitats with respect to predator visual systems would greatly broaden our fundamental understanding of the evolution of rapid color change. We tested whether whole-body color change provides water anoles (Anolis aquaticus) with camouflage against avian predators and whether these rapid changes allow them to shift between environment matching and edge disruption. We manipulated A. aquaticus placement in natural microhabitats and used digital image analysis to quantify color matching, pattern matching, and edge disruption produced by microhabitat-induced color change. Color change reduced lizard detectability to predators in microhabitat-specific ways. Environment matching was favored when lizards were in solid-colored microhabitats, regardless of exposure to predators. Edge disruption was instead induced by high exposure and varied by body region. We provide the first evidence that rapid color change permits a tetrapod to flexibly employ the most optimal camouflaging strategy by form (e.g., color matching vs. edge disruption) to minimize detection in the eyes of its predators.