The cochlea is a snail shaped chamber which is  filled with liquid and lined with cells that have tiny hairs on top-the cells are called hair cells .Once the stirrup hits the cochlea it sends waves through the liquid inside it. These waves move the tiny sensitive which make up the start of the auditory nerve

 

Horses need to have a good hearing as well as they actually have many predators in the wild — they are a flight animal and rely heavily on their hearing, which is much better than their sight. The horses range is 55 herz to 33 kiloherz. They can move their ears in any direction the sound came from.  

Pigeons have a low hearing frequency which allows them to detect storms and hear over a long distance.

 

From <https://www.thedodo.com/10-animals-with-amazing-hearing-1133474502.html> 

And <http://wonderopolis.org/wonder/how-can-dogs-hear-things-we-cant-2> 

surgical correction and hearing devices

From <http://www.hearingloss.org/content/types-causes-and-treatment>  

your family pet can hear about two times better than you!

they can also hear sounds approximately four times farther away than humans.

dogs have a much better hearing range than we do. What you hear at 20 feet, your dog can hear from 80 feet away.

The reason dogs can hear better then is that they have 18 or more muscles that control a dog’s pinna, or ear flap. These  muscles allow a dog to finely tune the position of his ear canal to find a sound, hear it more accurately, and from farther away. For this reason, dogs with upright ears, like terriers, tend to have superior hearing to dogs with floppy ears, such as hounds. It also means that dogs are much more sensitive to loud noises than are humans. Loud noises that are tolerated by humans may be scary or even painful to dogs.

From <https://www.doghealth.com/ears/hearing-in-dogs>