Marine mammals use a wide variety of sounds to communicate with each other. We do not know how sound is produced by many species of marine mammals. Although the term "vocalization" is commonly used to refer to calls that are produced by marine mammals; it does not imply that marine animals are using vocal folds to produce the sounds. Marine mammal sound production may have very little in common with human speech. (See How do marine mammals produce sounds?) Marine mammal calls can be soft or loud, short or long, and composed of high or low frequencies.

Marine mammals produce other sounds, like the sounds produced by a whale breaching or slapping its flippers. The animals may intentionally slap their bodies on the water or slap body parts together to make distinct sounds. The details of these behaviors may help shape these sounds. Marine mammals may unintentionally produce sounds, as a by-product of other activities. For example, swimming produces sound, but it is unlikely that animals swim in special ways to send messages with these sounds. Future research will help us understand which animal sounds and behaviors are designed to convey specific messages.

Marine mammal sounds differ among species, even when the sounds are used as part of the same behavior. For example, the echolocation sounds of dolphins, orcas, and sperm whale are very different in frequency and length. The following sections group sounds based on their function and social context.

References for: How do marine mammals communicate using sound?
• Tyack, P.L. 1999. Communication and Cognition. Pages 287-323 in Reynolds, J.E. III and Rommel, S.A. (eds.). Biology of Marine Mammals. Smithsonian Institution Press, Washington D.C.
• Tyack, P.L. 2000. Functional Aspects of Cetacean Communication. Pages 270-307 in Mann, J., Connor, R.C., Tyack, P.L., and Whitehead, H. (eds.). Cetacean Societies: Field Studies of Dolphins and Whales. University of Chicago Press, Chicago, IL.

For more information on how other marine animals communicate using sound, use the following links:
Marine Mammals	Fish	Invertebrates