The first thing we discussed with regards to communication is that animals have a variety of means of communicating. The method depends largely on the environment. For example, the mole rat lives most of its life underground. It's communication involves beating its head on the roof of its tunnels and feeling vibrations generated by other mole rats. A nocturnal rodent would probably use sound or scent to communicate with other individuals.
Many signals appear to have evolved from intention movements .
Other signals may have evolved from displacement activities seemingly irrelevant activities that occur through stimulation of the involuntary nervous system. Threat displays against competitor for territory or mating opportunities. Try to appear as big and strong as possible. Typically want to avoid direct contact. Displays to attract a mate.