The biological functions of coloration in animals are sometimes surprising. Color can attract mates, intimidate enemies, and distract predators. But color patterns can also conceal animals from detection. Concealing coloration is unusual because it is an adaptation not only to the visual features of the environment but also to the perceptual and cognitive capabilities of other organisms. Judy Diamond and Alan Bond bring to light the many factors at work in the evolution of concealing coloration.

Animals that resemble twigs, tree bark, stones, and seaweed may appear to be perfect...