sounds intentionally produced by animals that may be used for communication, navigation, and feeding. In humans, air is moved from the lungs and across the vocal folds (also known as vocal cords). The vibration of the vocal folds produce sounds that are formed into words and other vocal communication signals. We do not know how sound is produced by many species of marine mammals. The term vocalization is commonly used to refer to sounds that are produced by marine mammals; however, the use of the word vocalization does not imply that marine animals are using vocal folds to produce the sounds.