1. Whistles: Whistles are high-pitched, clear, and tonal sounds that are distinct to each individual dolphin. They often start at a high frequency and then decrease gradually. Each dolphin has its signature whistle known as a "signature whistle," which is used for individual identification and communication.
2. Clicks: Clicks are short, sharp, and high-frequency sounds that dolphins use for echolocation. They emit a series of rapid clicks to create a "sound picture" of their surroundings. By interpreting the echoes of these clicks bouncing off objects, dolphins can locate, identify, and track prey, obstacles, and other important objects in the water.
3. Pulsed calls: Pulsed calls are a series of short, repetitive clicks that are grouped together in bursts. They are typically used for communication and often vary in structure, duration, and repetition rate depending on the purpose and species of the dolphins. Different pulsed calls can convey information such as distress, aggression, sexual attraction, or cooperative hunting.
4. Buzzes: Buzzes are low-frequency sounds that are similar to whistles but lower in pitch. Buzzes are also produced during social interactions and serve various functions such as greeting, recognition, and expressing excitement or contentment.
5. Screams and Squawks: Dolphins sometimes produce high-pitched screams or squawks that may signal distress, aggression, or pain. These sounds are less common and are often associated with specific behavioral contexts.
6. Song: Some dolphin species, particularly the bottlenose dolphins, are known to produce complex vocal displays or "songs." These songs are long sequences of repeated or alternating sounds that exhibit structure and tonal patterns unique to each group or population of dolphins. They are thought to play a role in territorial defense, group coordination, and mating behaviors.
The repertoire of sounds produced by dolphins is diverse and still not fully understood. Scientists continue to study dolphin vocalizations to gain insights into their communication, behavior, social dynamics, and adaptations to their aquatic environment.