Marine mammals have long been known to use echolocation systems to move and hunt, using the bouncing waves they emit to locate objects. To find out how cetaceans adjust their hearing, the experts followed a false killer whale, also called a black killer whale ( Pseudorca crassidens ), to which they attached a sensor to measure its electrical activity in the brain. They first made him hear a neutral tone and then a sequence of five-second pulses of sound at 170 decibels. After some time, the animal learned that the neutral tone of a beep preceded the intense sound, so it adjusted its hearing in a way that minimized the effect of the loud sound.
According to one of the study's lead authors, Paul Nachtigall, the whales may have developed their sophisticated sense of echolocation to protect themselves from their own noises that can exceed 230 decibels.
The results of this work can help protect these animals in their environment , says the expert. "The research makes us more optimistic. Dolphins and whales can adjust their hearing to protect themselves if they are properly warned. What we want to define now is how to give them that warning effectively," Nachtigall said.
