Survival in the animal kingdom depends on how well adapted a species is, allowing it to obtain food, reproduce, and meanwhile not get eaten by predators or destroyed by competition.
Camouflage is one of the primary adaptations nature has provided that allows animals to go undetected and increase their chances of survival. It allows them to hunt without being seen by their prey, and it allows them to escape detection from those that would prey upon them.
Perhaps the most familiar form of camouflage is mimicry or background matching, that is, exhibiting patterns and/or colors that allow an animal to visually blend in with its surroundings. The forms this camouflage takes are practically endless: the spots of a leopard allow it to go unseen in the forest, while insects such as the praying mantis are adapted to look like leaves or flower petals, thus fooling their prey into a false sense of security; the feathers of owls and the wing patterns of moths and butterflies make them appear as the bark of a tree.
However, some cephalopod species have another technique that chameleons lack: changing shape. Such species are able to change the physical structures of their bodies to mimic the shapes of coral or rock on the ocean floor, a sight that appears almost magical to behold.
Rather than blending in with their environments, the color of some animals causes them to stand out and serves as a warning color, or aposematism, to other animals to stay away. There are many species of poisonous frogs, for instance, that display striking hues, such as bright blue, red, or orange, or have spots or stripes of color, signaling that they are toxic. Some species of poison dart frogs are poisonous enough to kill a human.
There are other forms of camouflage that are adapted to the behavior of other animals. African zebras, for instance, display long black and white stripes of fur on their bodies. While their color does not match the earth tones of the African savanna, their striped pattern makes them collectively indistinguishable from each other as a herd. This makes it more difficult for a lion or some other predator to single one out and hone in on a specific target. Their color also accounts for the fact that lions, one of their main predators, are color blind and unable to distinguish zebras from their environment.