Although humans can only use about 1% of their vocal power through speech, some animals use up to 100%. The secret to its powerful sounds? They have a very wide mouth and use their body intelligently to direct sound. The research results have been published in the Journal of the Acoustical Society of America.
Air movement
Animals make sound by moving air from the lungs through the throat and mouth. Slowly moving air must become a rapid back and forth motion to produce sound.
In each phase or movement some of that sound is lost. In fact, only about 10% of the aerodynamic power produced in the lungs reaches the throat.
The soft tissues in the throat absorb sound even more. However, then there is the efficiency of radiation: the amount of sound that is transmitted through the mouth.
Some birds and small mammals can scream as loud as a human being. But what is the difference between how and why humans and animals scream?
Why can they do it and we can’t
Animals have three main characteristics that enhance their vocal efficiency: wide mouths, a very high frequency, and the ability to turn their entire body into an acoustic reflective chamber.
“Human speech involves a great variety of vowels and consonants that are formed using a lot of variation in the lips, tongue and jaw. For that you need a low tone, so that that variation is very clear and separate from the vowels of the consonants, “explained Ingo Titze, one of the study’s lead authors.
However, animals that need to send a long-range signal do not use the same sound discrimination and use a higher pitch.
They use their whole body to scream
Animals, particularly small birds and mammals, can also use their entire body as a deflector. A baffle is like a box that contains a speaker. That is, a reflective surface that points the sound forward.
“The person in front of the deflector hears much better than the person behind it,” argues Anil Palaparthi, a co-author of the research.
Thus, they tilt their head back and sometimes retract it towards their body. Human beings, on the other hand, have a relatively inflexible neck that does not allow us that same function.
