Question of the month

During an interview with Peter Scheifele, Bioacoustician at the University of Connecticut, Whales online asked him the following question :

Do whales hear the way that we do?

P. S.:

First, the ears of whales are not exactly like ours. They have no pinna or ear flap, the outer ear canals apparently are no longer used, and many toothed whales hear via their lower jaw. The terrestrial animal ear bone is a part of the skull itself, but this is not so in whales. This probably reduces the amount of flow noise that the whale would have to hear as it swims. Although they have the same three bones of the middle ear as other mammals do, these bones are not connected to the eardrum.

The inner ear and neural system of whales have adapted to enable them to hear and decode very low or very high frequency sounds, depending upon species. Humans cannot hear some of these frequencies. The mysticete whales (also called baleen whales) tend to produce and use very low frequency sound, while odontocetes (also called toothed whales) make use of very high or ultrasonic frequencies for echolocation.

Second, sound behaves very differently in a water medium than in air. For one thing, sound travels five times faster in water than it does in air. Sound waves also behave differently depending on depth, temperature and salinity, sometimes becoming "trapped" in sound pathways or "ducts". Also, in water, it can be difficult to locate the source of a sound.

In reality, presently we don't know exactly what whales hear. Scientists have given hearing tests to some cetaceans in captivity, but these tests have usually been run in pools or bays that may not be representative of their natural environment. Therefore, what and how whales hear is still poorly understood. All we know is that whales rely more on the use of sound than perhaps any other animal on Earth. That is why there is growing concern over the amount of noise that mankind is putting into the oceans and the effect it may have on whales. People have laws and equipment to protect themselves against deafness resulting from exposure to noise, whales do not. Yet, a deaf whale is not likely to survive very long.

Portrait of Peter Scheifele

Communication : music to swim by