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Honest signaling has given rise to two forms of mimcry: Batesian mimicry, in which a dangerous signaler is imitated by a harmless mimic, and Mullerian mimicry, in which two dangerous species evolve mutual imitation to the benefit of both. A good example of Batesian mimicry is that of the Pseudotriton ruber salamander, which closely resembles another salamander, Notophthanlmuus viridescens. The Notophthalmus salamander is unpalatable to birds, and they soon learn to avoid these salamanders. The same birds also avoid the Pseudotriton salamander due to its close resemblance to that of its unpalatable cousin. Mullerian mimicry often occurs when two similar species, both of which are dangerous, have some overlapping habitat. By resembling each other, a predator that learns to avoid one will be more likely to avoid the other. In this case, the predator saves itself a hard lesson learned twice, and the mimics avoid a sacrificial encounter.

From Signaling to Communication: Problems of Definition

There are inherent problems in defining communication, which is generally concerned with intentional signals given to alter the behavior of the receivers. Some signals are not intended for this purpose and so we will exclude them from communication. But determining the intent of a signal can be difficult. For instance, the Cleaner wrasse fish performs a display to attract bigger fish, which line up to have their parasites picked out of their gills. This is a mutualistic symbiotic relationship; the bigger fish have their parasites removed and the Cleaner wrasse gets a nice meal. But is the display really communication? Certain bats hunt Tungara frogs, which have two main vocalizations--a high pitched whine and a low pitched chuck. Bats can only hear the chuck, and female Tungara frogs are more attracted by this sound. The signal is intended to attract females, but it also clues a hungry bat in to the location of a frog. The bat's behavior is modified as a result, but the signal was not intended for the bat. Consider a signal to an intended receiver where the response will be mutually beneficial. Flower colors, for example, have evolved to attract specific pollinators. The result is mutually beneficial--the pollinator enjoys a meal and the flower has its pollen spread, but would we really say the flower is communicating with its pollinator? These are some of the problems we face when defining communication, and as a result there can be no hard and fast definition.

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