Intraspecific and Interspecific Sound Variations in Cetacea, With Special Reference to: Megapera novaengliae and Tursiops truncatus

Defense Date


Document Type


Degree Name

M.S. Marine Biology

First Advisor

K. Ronald

Second Advisor

Curtis Burney

Third Advisor

Michael M. Bryden


Animal bioacoustics is described as the study of sounds in non-human animals including acoustic communication, mechanisms of sound production, auditory function and anatomy, sonar, acoustic tracking, and the effects of anthropogenic (human-made) and environmental sounds on animals (Mellinger 2001). In the last decade, sounds produced by marine mammals have been studied in order to determine behavior, taxonomy, evolution, and many other characteristics of these animals.

Marine mammals produce sounds in many different manners, and each sound produced is appropriate to a particular behavior or situation. Odontocetes or toothed whales exhibit two main types of sounds: clicks and whistles. The "clicks" are used to find food, to echolocate in their environment and for other important behavioral aspects. Whistles are used for basic communication, to describe a physical state, or to produce a distinctive sound particular to that individual (identification). This animal's series of whistles are distinct from any other member of the group; and are called "signature whistles." A signature whistle distinguishes an animal from the others and provides a way for cetaceans to recognize and bond with others.

Mysticetes or baleen whales produce many types of sound; including the grunt, the whistle or moan, pulse trains and blowhole sounds. These are used for different types of behavior than those of odontocetes. These sounds are produced to determine status, mating behavior, or pod location relative to other members of the species (not for basic communication). It has been determined that these sounds can change through seasons, within members of the group, sex, and location in the water column. Therefore, the understanding of the physiology of these animals and the sound production of the mysticetes is a crucial factor in helping with studies of behavior and identification.

The in-depth study of different cetacean species' sounds may deepen the understanding of the significance of sound produced by these animals and it can correlate the changes in sounds with body length, sex, behavior, and ecology. The search for the role of sound in the everyday lives of marine mammals is getting clearer with new technologies. As species and even individuals are identified, scientists get even closer to the meaning behind these sounds. One of the advantages of studying sound is that bioacoustics allows use to identify the animals more precisely and help with identification when the animals are not visible.

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