Mechanical communication

Communication through vibrations may be either substratum-coupled (through vibrations in the ground or other substrate), or acoustic (through the air or water). Among spiders, web vi­brations are used to communicate between a courting male and the web's owner (he plucks out a song) or to determine the type and placement of prey that have blundered into the web. The web vibration patterns differ among species. Other animals that use a substratum-coupled vibration system for communication include water striders and leaf hoppers.

Acoustic communication is accomplished as vibrations through air. Spiders also use sounds for communication.

Visual communication

With good vision, it became possible for many animals to use a new channel for communica­tion. Among those spiders that have good vision, courtship dances perfumed by male spiders help to get the female in the mood. Other animals have more spectacular, albeit still silly, courtship dances.

Competition among males for the most impressive displays to attract females has led to orna­ments, colors, badges, and other decorations to attract females and/or ward off other male competitors. The red epaulets of the redwing blackbird, for example, are necessary for male birds to defend their territory. If the epaulets are painted black, the male can no longer chase off competing males (in fact, he is not taken at all seriously and is completely ignored by his rivals). Among other animals, the need to impress females has gone to an extreme. The male peacock, for example, is required to put up with his ungainly and brightly colored tail and ac­cessory plumage to impress females. This is despite the fact that these feathers make him more susceptible to predation and are metabolically expensive to construct.

Generally, sexual selection leads males to extremes and is driven entirely by female prefer­ences and competition among males for mates. This has produced some extremely silly look­ing and conspicuous males over evolutionary history.

Imprinting

A specialized type of "programmed learning" seen in many higher animals is a process known as "imprinting". The first experimental analysis of imprinting was done by Konrad Lorenz on geese hatchings. The first job of a gosling is to identify its mom so they can follow her should she start to wander off. Goslings are pre-programmed to follow the first object pro­ducing the species-specific call. This object is then identified as "mom". It doesn't matter what the object is, just as long as it emits the proper call and moves. Researchers have had fun with this effect by imprinting ducklings on a model train that emitted quacks from the speaker. Ducklings would dutifully follow the train just as if it were mom.

Another characteristic of imprinting is that this specialized learning must occur within a certain time-window known as the "critical period". Ducklings that are first exposed to mom at 1 week of age will not follow here, since that is outside the critical period for learning the task.

Song learning in some birds (doves, for example) is entirely innate. Young doves raised with­out exposure to adult song will sing the adult song perfectly the first time they try it. Most other birds, on the other hand, need exposure to the adult song during a narrowly defined criti­cal period in order to imprint and learn the proper song.

Birds stake out their territories by singing. After the territories are agreed upon, it is to every­body's advantage to recognize neighbors. This way, a bird that hears a neighbor's call knows that he doesn't have to pay special attention to the situation since the territorial boundaries have already been agreed upon. Only when a stranger enters the territory and begins to sing does the male have to give it special attention. Some of the song motifs have a genetic component.

How does a young bird know which noises to pay attention to? The answer is that the young bird has some idea of what to listen for – an innate "neural template" that gives the general parameters of the species-specific song. The neural template theory suggests that the songs of unrelated birds do not fit the general configuration of genetically predisposed song structures. The template (or idea of how the species song should sound) is slightly sloppy; allowing for the creation of dialects and individual, bird-specific songs.

Another example of restricted learning is food aversion. Animals that eat a novel food and then get sick will avoid that food from then on. In this example, a Blue Jay has eaten a Monarch butterfly. Monarch butterflies feed on milkweed as larvae and concentrate milkweed chemicals in their skin. These chemicals make anyone who eats a monarch sick (at the very least; the toxins are cardiocides that attack the heart). Birds that have experienced the stomach upset brought on by eating Monarchs will avoid Monarchs from that day on.