Human Interaction
Though some observers suggest that undue fascination has been placed on the whales' songs simply because the animals are under the sea, most marine mammal scientists believe that sound plays a particularly vital role in the development and well-being of cetaceans.
Researchers use hydrophones (often adapted from their original military use in tracking submarines) to ascertain the exact location of the origin of whale noises. Their methods allow them also to detect how far through an ocean a sound travels. Research by Dr. Christopher Clark of Cornell University conducted using military data showed that whale noises travel for thousands of kilometres. As well as providing information about song production, the data allows researchers to follow the migratory path of whales throughout the "singing" (mating) season. An important finding is that whales, in a process called the Lombard effect, adjust their song to compensate for background noise pollution. Moreover, there is evidence that blue whales stop producing foraging D calls once a mid-frequency sonar is activated, even though the sonar frequency range (1–8 kHz) far exceeds their sound production range (25–100 Hz).
Prior to the introduction of human noise production, Clark says the noises may have travelled right from one side of an ocean to the other, agreeing with a thirty-year-old concept blaming large-scale shipping. His research indicates that ambient noise from boats is doubling with each decade. This has the effect of reducing the range at which whale noises can be heard. Environmentalists fear that such boat activity is putting undue stress on the animals as well as making it difficult to find a mate.
Read more about this topic: Whale Vocalization
Famous quotes containing the words human and/or interaction:
“There seems to be a kind of order in the universe, in the movement of the stars and the turning of the earth and the changing of the seasons, and even in the cycle of human life. But human life itself is almost pure chaos. Everyone takes his stance, asserts his own rights and feelings, mistaking the motives of others, and his own.”
—Katherine Anne Porter (1890–1980)
“Recent studies that have investigated maternal satisfaction have found this to be a better prediction of mother-child interaction than work status alone. More important for the overall quality of interaction with their children than simply whether the mother works or not, these studies suggest, is how satisfied the mother is with her role as worker or homemaker. Satisfied women are consistently more warm, involved, playful, stimulating and effective with their children than unsatisfied women.”
—Alison Clarke-Stewart (20th century)