Many of the dolphin and whale species are known to respond when they hear distress signals, even of other species. Some are known to attack other animals that are harming another of their kind. And they have shown interest in humans and have made attempts to communicate with us in their own fashion. Surely communication is one of the most fascinating aspects of the dolphins. But dolphins seem to have a very sophisticated form of communication.
Some people believe that they have a formal language.
They make several types of sounds to accomplish this, the most sophisticated of which is echolocation, a type of sonar far more advanced than human's. Further research and analysis of dolphin communications may be the key to understanding the apparent complexity of their social order. Obviously, the complex behavior of dolphins is not fully understood. We can only conjecture about the meanings of their behavior and continue to investigate by observing their natural activities and learning more about the unique environment to which they are adapted.