Look Deep Into My EarsLast time, we took a journey into the eye of a cat and learned how differently our furry companions see the world we share. In this article, we will focus in on the intricacies of how our cats use their unique sense of hearing.
Those warm, soft triangles of fur on either side of a cat's head are yet another marvel of feline engineering technology. In much the same way as a sophisticated satellite dish rotates and adjusts in order to best position itself for receiving a signal, the cat's external ear, or pinna, can rotate up to 180 degrees to locate and then identify even the faintest of noises - many of which are not perceptible to humans. Click your fingernails behind a cat's head and observe as the ears first move and adjust to locate the sound, and then reposition to identify it. Next, the cat will turn its entire head around to visually identify your hands behind her. It is fascinating to watch a cat as she strolls along her business, then suddenly stops, swivels her ears around, then pounces upon some unsuspecting prey rustling nearby.
Most of us know that dogs can detect those special high-pitched whistles designed to produce a frequency of sound far too advanced for mere humans to hear, but cats are capable of hearing much higher frequencies than dogs and are only slightly inferior at the lower end of the frequency scale. Cats are able to detect even the smallest differences in the sounds they hear, distinguishing differences of as little as one-tenth of a tone, which helps them identify the type and size of whatever is emitting the noise. This heightened sense of hearing is especially important in wildcats, which depend on hunting for survival because it gives them crucial information about the size as well as type and location of the prey they are preparing to hunt - this can be very important when making the decision to pursue or to let the prey animal go about it's own business. It also enables both wild and domestic feline mothers to hear faint squeals of distress from their cubs or kittens if they stray too far away. A cat as far away as 3 feet from the origin of a sound can pinpoint its location to within a few inches in a mere six one-hundredths of a second. Cats also can hear sounds at great distances — four or five times farther away than humans!
The ears also serve in another way that is vital to successful feline life. The vestibular apparatus, housed deep in the cat's inner ear, is responsible for the cat's remarkable sense of balance. The tiny chambers and canals of the interior ear are lined with millions of sensitive hairs and contain fluid and microscopic floating crystals. Whenever the cat changes it's physical position, these delicate hairs detect even the slightest of movement in the fluid and crystals and then rapidly send those messages to the brain. This gives the brain accurate readings on the body's position so that it can send the signals for the necessary muscles to compensate, thus achieving a “cat-like” perfect sense of balance.
The Cat's Inner Ear and Sense of BalanceThe mechanism in a cat’s inner ear is very similar in principle to the instrument in an airplane called the "artificial horizon" or "altitude indicator". This is the gauge that interprets the position of the plane's wings in relation to the horizon and reports this information to the pilot. When a cat loses its balance and actually takes a spill, the vestibular apparatus kicks in. This helps the cat register which direction is up and triggers the "righting" reflex that cats rely on to turn themselves in midair, adjusting the orientation of the body so that they land squarely on all four feet. However, recent studies disprove the old wife’s tale that cats will always land on their feet. It seems that falls from a shorter distance to the ground are actually more dangerous in terms of injury to the cat than falls from a longer distance to the ground.
The vestibular apparatus, along with the tail acting as a counterbalance, enables the cat to jump with an almost military-like precision, reaching into the air to catch onto a tree limb, catch flying prey or physically change it's location from a solid, stable surface to a non-stable surface. The Manx, a tailless breed, is thought to have an especially sensitive vestibular apparatus to compensate for the lack of the tail's counterbalancing properties.
Cats, like humans, can also experience hearing problems or even total deafness due to disease, infection, outer-ear trauma, inner-ear damage (from excessively loud noises) or simply old age. The cat's ability to detect high frequencies particularly declines as the eardrum thickens with age. This condition not only affects the cat's hunting skills; it also can compromise the feline's ability to heed noises signaling danger. In domestic cats, however, deafness is most commonly hereditary. Although inherited deafness has not been genetically related to specific breeds, the dominant gene responsible for producing white hair is sometimes associated with inner-ear abnormalities that often lead to deafness. Incidences are highest in white cats with blue eyes; white cats with eyes of different colors are often deaf only in the ear on the blue-eyed side.
Imagine that your hearing was amplified 4 times over ... that you could hear so well that you could hear electrical currents. Can you imagine how noisy your world would be? A cats hearing IS amplified 4 times greater than ours. When you plug your hair dryer into the wall, your cat can hear the electrical current before you even turn the hair dryer on. Amazing! Cats have 20 muscles in each one of their ears, and they can hear really high frequencies that even dogs can't hear. Maybe this is why cats sleep so much - to tune out our noisy world!
Written by Gaye Flagg
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