The False Killer Whale Knows to Focus Acoustic Waves on its Prey

Echolocation is very efficient sense of some cetaceans and bats, and considered a sixth sense. In a delphinid mamals like false killer whales , the beam of sound waves can be focused on prey or difficulty identified objects, it is a bit like the development of a camera.

Kina, the false killer whale used for experiments on wave beams. © Aude Pacini

Some animals have a sixth sense: echolocation. This is the case of bats and many cetaceans. New studies on the beam of sound waves emitted by the false killer whale (Pseudorca crassidens), a marine mammal of the dolphin family, shows that the animal is able to adjust the transmitted beam according to the prey he seeks to identify.

Echolocation is a sense of great benefit to these marine species. At great depths or in brackish water, the view is indeed somewhat superfluous. Through nasal sacs placed on the forehead, cetaceans send waves passing through a bag of grease called the melon. Acting as a lens, it reduces the beam scattering.

Echolocation, sixth sense of cetaceans

Researchers already knew that some whales were able to direct the beam toward a desired direction. The false killer whales, they may in addition alter the characteristics of waves when prey is more difficult to identify.

To realize this, researchers at the University of Hawaii resulted experiments of a false killer whale, named Kina, to her recognition of a cylinder with very accurate dimensions . At the end of the training period, Kina recognized the difference between two cylinders whose dimensions were distinct and received rewards accordingly. But when she had a third mid-size cylinder , she experienced more problems at all apart.

Focus the waves on a prey

To discover the elements involved in such cases, the researchers placed sensors (hydrophones) between Kina, the emitter, and the cylinders she was trying to identify. They thus obtained a snapshot of the wave emitted by the whale, revealing a previously unknown behavior. When Kina fails to identify a cylinder, it reduces the width of the wave beam, to obtain a more accurate representation of the object it seeks to identify. Somehow, like how the human eye works to focus, only with sound instead of light, the false killer whale is able to focus the beam on a target. The results were published in Journal of Experimental Biology.

Thus, it can optimize the amount of waves reflected from the target object, and avoid being disturbed by those returned by other objects. Nevertheless, it is not yet possible to know what actually takes place in the brain of these animals: it is this action guided by the nasal sacs? The melon is responsible? It is also not certain that all cetaceans are capable of achievements performed by the false killer whales.

Tagged Acoustic Waves, Echolocation, False Killer Whale, whale