Many animals possess camouflage markings that reduce the risk of detection by visually hunting predators. A key aspect of camouflage involves mimicking the background against which the animal is viewed. However, most animals experience a wide variety of backgrounds and cannot change their...

Various conspicuous signals in nature promote initial and learned avoidance by predators. It is widely thought that such signals are most effective when highly symmetrical in features such as size and shape, supported by recent laboratory experiments with domestic chicks and artificial prey....

Many animals bear colors and patterns to reduce the risk of predation from visually hunting predators, including warning colors, camouflage, and mimicry. In addition, various species possess paired circular features often called "eyespots," which may intimidate or startle predators preventing or...

Some parasitic cuckoo chicks display a vivid-colored gape to their host parents when begging for food. Their mouth color was once regarded as a supernormal stimulus, yet owing to a lack of experimental support, the idea has fallen out of favor. However, previous experiments were conducted...

Two, logically distinct but sometimes compatible, mechanisms of camouflage are background-matching and disruptive coloration. In the former, an animal's coloration comprises a random sample of the background, and so target--background discrimination is impeded. In the latter, object or feature...

Animal coloration has provided many classical examples of both natural and sexual selection. Methods to study color signals range from human assessment to models of receiver vision, with objective measurements commonly involving spectrometry or digital photography. However, signal assessment by...