Variations in loudness, speed, and pitch convey different messages. In captivity, attempts to teach dolphins to speak are made. Common dolphins, however, are not easily trained despite their friendliness. In captivity, common dolphins are very uncharacteristically shy. Sound is the primary sense.
Vision is often difficult, espcially in dark and murky waters.
Common dolphins have very few enemies. Those they do have to worry about are sharks and killer whales. Habitat Common dolphins are fond of coastal waters, but are also found well out to sea. Generally, they prefer surface temperatures greater than 10 degrees Celsius. When swimming, schools follow and dive over prominent features of the ocean bottom.