Hearing Your Way Around: Part 2 - Echolocation in Whales and Dolphins

The suborder of cetaceans (whales and dolphins) known as toothed whales (as opposed to those who have baleens) includes dolphins, porpoises, sperm whales, and orcas. Toothed whales are highly skilled at using echolocation which helps them to navigate and “see” at greater distances than would otherwise be possible. The aquatic environment allows sound waves to travel easily through the water for very long distances which makes it an excellent habitat for the use of echolocation.

 

Dolphins and whales emit a precise beam of sound emitted in the form of clicks which are sent out, bounce back and received by the melon area as the illustration demonstrates. This amazing feature of dolphins and whales is something that we have only become aware of in the past few decades. The famous oceanographer and explorer Jacques-Yves Cousteau first wrote about his suspicions that dolphins were using a type of sonar system in the 1950's and later research proved that his initial observations were quite accurate.

 

In fact, this world of sound is so important to whales and dolphins that they rely on it to navigate the waters, to hunt and feet, to communicate with others, to mate, and form bonds with their offspring. This sensitivity to sound, and the fact that it is such an intricate part of their lives, is why the use of sonar testing and other acoustic pollution created by humans is having such a devastating effect on cetaceans resulting in confusion, loss of communication ability, and even death in many animals. (To learn more about the harmful effects of sonar and noise pollution on marine life, check out Detrimental Effects from Anthropogenic Noise on Marine Life.)

The issue of sound is also one of the reasons why keeping dolphins in captivity is so harmful to the marine mammals. The small

enclosed nature of most tanks creates a constant reverberation of sound that can be disorienting, even maddening, for a dolphin that has been captured and forced into a tank.

This issue is such a problem that many, such as the UK, have taken steps to abolish marine mammals captivity all together. Several conservationist and animal rights groups are calling for the same type of measures in the US. As we have learned more about the biology and behavior of dolphins and other marine mammals including their reliance on sound, we have learned that keeping a dolphin in a tank is not a healthy situation...dolphins belong in the ocean where they can swim and communicate properly.