If you have had the opportunity to be close to roosters, you will know that their morning song can become quite loud and penetrating. If you are near a rooster while emitting your particular chant, you will be exposed to a sound wave that can exceed 100 decibels, which is enough to cause severe damage to the auditory system. So, how do roosters not deafen themselves with their song?
Why do Scientists roosters have so loud sound?
To clarify this question, a team of researchers from the Universities of Antwerp and Ghent, Belgium, conducted a study of the ears of chickens and roosters. To determine the sound levels to which the animals expose when they sing. And for this, the researchers attached microphones to the heads of three of them, right in the openings of their ears.
Together, they recorded the song of the animals from different distances and later, they made computerized micro tomographies of the hens and the roosters; this allowed them to reconstruct the morphology of their auditory canals digitally.
The measurements revealed that the sound emissions produced by the roosters, had enough power to generate severe hearing damage; songs were often recorded that could reach up to 140 decibels; an acoustic intensity comparable to that produced by a jet when it takes off.
The researchers discovered that when animals open their beaks ultimately. What happens when they sing, their auditory canals does not entirely close. So, this protective mechanism, which can be described as anatomical buffers for your ears. That allows roosters to be so noisy without self-inflicting hearing damage.
Once the protective mechanism in the roosters gets active, the researchers focused on the chickens. Surprisingly finding that their auditory canals do not close entirely due to small morphological differences.
Roosters are territorial creatures, and their song seeks to keep potential competitors away from their henhouse. In this way, the stronger the crowing, the higher will be its reproductive success. This research points to the idea that over time, the crowing evolved to become stronger and stronger. And to this extent, the characteristics of their auditory canals changed in response.