Hearing medical terms: Hertz (Hz), Decibel, auricle, auditory ossicle, middle ear, inner ear, Aural hematoma
Sound energy is a wave. The wave, like waves at the sea shore, can come quickly together, or come slowly and far apart. This frequency of waves is called Hertz (Hz). One Hz is 1 cycle or wave/second. Sound ranges from 1-100,000 Hz. Using the abbreviation of k for 1,000 (kilo), we can also say sound reaches 100 kHz. We perceive Hz as pitch, and the higher frequencies have higher pitches. A mouse shriek has a high pitch, while the rumbling of an earthquake has a low pitch.
Hertz (Hz) and Species
Hear 20 to 23 kHz, and are better able to hear sounds at lower frequencies.
Dogs: Hear sounds to 45 kHz.
Cats: Hear sounds to 64 kHz.
Bats: Hear sounds to 110 kHz.
Porpoises: Hear sounds to 150 kHz.
Younger people and animals generally have more acute hearing than adults and can hear sounds in the full range of Hertz.
Each pet’s ears have a distinct ear position, shape and carriage
Decibel is the measure of how loud a sound is. At extreme ranges—upper and lower—of hearing, a sound must be louder or, that is, be at a higher decibel, for it to be audible. Because our upper limit for sound is below that of dogs and cats, a high-pitched siren must be louder for us to hear than for our pets to hear.
Loud sounds cause pain, and our pets feel auditory pain far sooner than we can. We need to be considerate with how loud we turn our stereos and TVs.
Your pet has more than 10 muscles to move their ears which easily changes their ears’ shape and position—bending them, clasping them to their head, and turning them almost 180 degrees. Pets take advantage of ear mobility to signal emotions and intentions. Human ears are pretty tame in comparison, although they’re handy for jewelry.
Deafness: Fluid, Infection, Tumors, and Polyps
Fluid in the middle ear can make it hard for your pet to hear. If the fluid was introduced by flushing, it is usually absorbed within 7-10 days and your pet’s hearing will return. If the fluid is the result of allergies, your pet will be hard of hearing until the allergies are cleared up.
If your pet has a chronic ear infection, the infection can eventually cause the ossicles (bones) in the middle ear to thicken and harden so that they cannot transmit sound. With thickened ossicles, your pet will lose the ability to hear high-frequency sounds.
If your pet develops a tumor or polyp in their middle ear that blocks air movement, they may become deaf. Many of these pets are able to hear low frequency sounds that are conducted through bone rather than through air. With bone conduction, your pet can hear low frequency sounds—similar to what you’d hear with your fingers in your ears.
Many pets fool us into thinking they have normal hearing if they have at least one good ear. What you may notice, though, is that a pet with one deaf ear can’t locate the source of a sound as well as it could in the past.
An aural hematoma is hemorrhage and bruising within the ear. Animals with painful or itchy ears shake their heads so violently that blood vessels break within the ear causing an aural hematoma. The ear visibly swells. The best treatment for an aural hematoma is draining the blood through an incision made on the inside of the ear flap, and placing a tube in the ear so that blood will not pool in the ear. Without surgery and drainage, the blood clots stay in the ear for weeks, leading to scarring and a thickened or “cauliflower” ear.
Your pet is asking for help when they shake their head so hard the vessels inside their ears break. Work with your veterinarian to find out what caused the head shaking.