If you’ve ever woken up in the countryside, the unbearably loud crowing of roosters should be a very familiar sound for you. But why don’t they go deaf themselves?
My grandparents live in the countryside and everytime I sleep there I wake up at around 5 in the morning by a very loud "CUCK A DOODLE DOOOOOO". It was so loud it was impossible to sleep after that, but I never wondered why I would almost go deaf and the birds themselves didn’t. (I’m trying very hard here to not make some stupid joke about a loud cock in the morning.)
First of all: just like humans, chickens have tiny hairs in their ears and if those hairs get damaged, it destroys your hearing. That damage starts for humans already at around 85dB.
A Belgian team of scientists with the universities of Antwerp and Gent, who published their results in the scientific journal Zoology in the beginning of 2018, placed a microphone near the ears of the chickens to measure the sound. The crowing was much louder than they thought before, it was actually averaging around 100 dB from a meter distance, about the same loudness as a chainsaw. For the rooster itself, the sound could reach a maximum of 142,3 dB.
The scientists found that the hairs in the ears were not damaged by the sound of the crowing - which is very surprising at these extremely loud volumes. So, the researchers wanted to find out why this happens and they did.
Super Mutant roosters
The funny thing is: it’s not that the rooster’s hairs are strong enough to withstand the loud sound, but they have some sort of super mutant chicken ear shield. Half of the bird’s eardrum is covered by a soft tissue that protects the ear. Another piece of tissue covers the other half when the rooster tilts his head back to crow. It’s like they put their fingers in their ears to crow, except they don’t have fingers but super mutant chicken ear shield tissue.
Source: Phys & Zoology