Examining a Cat's Hearing: How Does it Work?

A cat's hearing is incredibly sensitive and it can hear high pitched sounds that humans cannot. This helps it in picking up the high-pitched squeaks of it's favorite prey, mice, and the ear is also very sensitive to rustling sounds. It is said that cat's ears are even more sensitive than humans or dogs.

A cat's ear is divided into three distinct sections, we can see the ear flap (pinna) and it is usually erect and pointing forward. If you watch the cat's ear it can turn towards sound as if to pick up that extra little bit of noise, and it will move to figure out the direction of the noise like a feline radar.

Sound waves are picked up by this radar system and the ear flap act like a funnel straight to the ear drum which is pulled across the ear canal. The middle ear has three tiny bones in it that act as a vibration source that transmits sound to the inner ear.

In the inner ear the sounds are converted into nerve pulses and sent through the acoustic nerve straight to the cat's auditory cortex, which is the part of the cat's brain that basically breaks down and understands the signals coming from the ear.

This function is extraordinary, like all animals, the auditory cortex will compare these sounds to images the brain has associated with in the past and stored in the memory bank. This is how cats, and other animals, can be taught how to react to sounds such as their names and respond to training by commands.

Humans can hear between 20,000 to 23,000 hertz while a cat can hear between 45,000 to 65,000 hertz. So your cat has roughly twice as good hearing as you do. That is why they seem to be chasing something you can't see sometimes, such as a wayward mouse or bug in your house.

The cat's ears are also vital to it because deep in the cat's inner ear is the vestibular apparatus that is responsible for the cat's extraordinary sense of balance. The chambers of the inner ear has several million of tiny, ultra-sensitive, hairs and contain fluid with floating crystals.

Whenever the cat moves or shifts it's position these hairs send the changes it detects in the fluid and crystals straight to the brain. This creates an almost instantaneous response back to the cat's muscles to compensate for the movement. It is also probably the reason the cat usually lands on all fours during a fall or jump. This sense of balance and compensation going on in the inner ear is probably working overtime while the cat is in the air.

Sources:
Gaye Flagg, About Hearing in Cats, The Cat Site