Nov. 10/2023

 

Listen Up to These Fascinating Facts About Your Cat's Ears

Jamie Lovejoy, DVM 

petmd.com

2/8/2023

Though they look like soft, fuzzy triangles, a cat’s ears are actually highly specialized & fine-tuned to

do much more than our own. Along with hearing, cat ears are made for hunting, hiding, & communicating. Here are some facts that may surprise you about your cat’s ears.

1. Cats Have Excellent Hearing

Anyone who has opened a can of cat food & had their kitty run to the kitchen from across the house won’t be shocked to learn that cats have much better hearing than people do.

When not being served by humans, cats must find & stalk small, fast prey, often in low light. This requires not only listening for very quiet sounds, but also those with a higher pitch. According to a review published by Louisiana State University, cats can usually hear sounds pitched almost 2 octaves higher than what humans can hear–& one octave higher than what dogs can detect. No wonder a mouse squeak is no trouble for them to hear!

For lower pitches, humans & cats seem to have similar limitations, though cats can hear these lower frequency sounds from much farther away because they have greater sound sensitivity. Due to their small size, cats are also at risk of becoming prey themselves, & this sensitivity allows them to detect threats that a human or dog might not pick up on.

2. The Feline Ear Is Made of 3 Parts

A cat’s ear has 3 parts: the outer, middle, & inner ear.

The outer ear is the visible portion: the pinna & the ear canal. A cat’s ear canal is much deeper than a human’s, funneling sounds trapped by the pinna down into the ear drum more efficiently. This is the most common part to be affected by an ear infection (otitis externa).

The middle ear is an air-filled chamber (bulla) separated from the outer ear by a thin membrane called the tympanic membrane or ear drum. It contains 3 small bones that transmit vibrations from the ear drum to the inner ear. It’s also connected to the back of the nose by a pathway called the eustachian tube, allowing the air to stay at a reasonable pressure.

The inner ear takes information from the middle ear & transmits it to the brain. It’s also the home of the cat’s vestibular (balance) system, which is incredibly sensitive & much more developed than a human’s ear, allowing them to be much more agile (& more likely to land on their feet!).

3. Cats Have Mobile Outer Ears

Humans have 6 muscles in our outer ear (pinna). Cats have 32. This anatomy lets them rotate their ears a full 180 degrees! Not only does this allow cats to use their ears to express themselves, they can point their ears towards faint & far-away sounds to hear them more clearly.

4. Cats’ ‘Henry’s Pockets’ Are a Mystery

One structure that is particularly obvious in cat ears (although bats, weasels, & some dogs have them as well) is the cutaneous marginal pouch. Also known as a Henry’s pocket, this is the thin flap of skin on the outside of the ear, & its significance isn’t clear. There is a theory that this skin flap helps them detect higher-pitched sounds, but it may also serve no function at all. But mites & parasites love this location, so your vet will routinely check it during a physical exam—especially if your cat has been itchy.

5.  Cats Are Born Without Ear Canals

When kittens are born, the ear canal is closed & cannot transmit sound from the outer ear to the ear drum. This means that until they are at least 1 week old, kittens can’t hear anything at all!

This cat ear anatomy likely protects them in the birth canal. Once the ear canal opens, the rest of their systems begin to mature, & they can hear progressively quieter sounds.

6. Deafness Is Common in White Cats With Blue Eyes

White cats with blue eyes are frequently completely deaf. The most common gene to be involved in this coat & eye color combination also seems to cause degeneration of the inner ear structures early in life. White cats with one blue eye are also commonly deaf in the ear on the side of the blue eye. There are a few genes that can lead to white coats & blue eyes, so not all cats with the combination are affected—but it is suspected that up to 80% are!

Monitoring your cat’s behavior around household noises may be the most effective way to try & determine if your cat is deaf. Unless there is an obvious structural abnormality, cats are very difficult to evaluate in the clinic for loss of hearing. Your vet can make noises & look for responses, but there can be many complications with this approach:

One-eared deafness cannot be assessed

A cat may choose not to respond

Cat whiskers are so sensitive that they may respond to vibrations & not just sound

A Brainstem auditory evoked response (BAER) test can be performed at some facilities to test a cat’s hearing. During this test, electrodes are placed in a way that they can pick up electrical signals from the nerves bringing information from the inner ear to the brain. This testing can be informative, but it’s not very practical in most situations.

7.  Normal Cat Ear Canals Are Self Cleaning

Unless instructed by your veterinarian, don’t clean away that normal waxy debris from the ear canal! Wax is produced in the canal to trap dust & pathogens that might affect the sensitive ear drum. Mammalian ear canals have specialized cells with hairs that automatically bring these pathogens away from the ear drum & toward the outer ear, where a cat’s normal grooming habits will dispose of them.

Putting unwarranted cleansers in your cat’s ear canal can damage this cycle & cause more harm than good. But if you are instructed to clean your cat’s ears, make sure you are using a product designed for the ear canal to avoid irritation.

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