 |
|
1 |
Ear drum |
|
2 |
Auditory canal |
|
3 |
Ossicles
- The hammer, whose handle is attached to the
ear drum.
- The anvil, whose body is connected to the
head of the hammer through an articular facet.
- The stirrup (4), whose head is connected
with the longer process of the anvil through the lenticular
bone.
|
|
4 |
The stirrup, which is attached to the oval
window ( = fenestra ovalis).
The oval window is the entrance to the atrium of the
cochlea, here the sound is transmitted into the cochlea. |
|
5 |
Round window (fenestra
cochleae), it works as leverage of the
sound pressure. |
|
6 |
Eustachian tube |
|
7 |
The three bony bows form the semicircular canals,
which are the sense of equilibrium. |
|
8 |
The vestibular part of the auditory nerve |
|
9 |
The cochlear part of the auditory nerve |
|
10 |
Cochlea |
 |
Click on the term to get a
description.
Click somewhere in the picture to enlarge the
picture. |
Organ of Corti 1)
 |
Click on the number to get a description.
Click somewhere in the picture to enlarge the
picture. |
What does the cat hear?
Frequency
The hearing frequency of a cat ranges from 40 to
65.000 Hz.
A human has a range from 16 to 24.000 Hz, a dog between 60 and
45.000 Hz. The deepest sound (infrasound) with 12 Hz can be heard by
the elephant, the highest sound (ultrasound) with 120.000 Hz can be
heard by the Beluga whale.
Example: 64 Hz correspond to the lowest tone on a piano, 65 kHz mean
that a cat can hear 2,5 octaves higher than a human.
For example, think about those animal collars, which are operated
via ultrasound, how uncomfortable and distressing those collars are
for the cat. Or think about those light switches and plugs operated
via ultrasound, how much they disturb a cat.
A cat is extremely sensitive to frequencies between 1.000 and 20.000
Hz.
Intensity
Also the intensity (dB = decibles), how loud a sound is, is
noticed by the cat 10 times more acutely than by a human, by the dog
it is heard 5 times more acutely.
Example: 30 dB correspond to an intensity caused by whispering. The
dog hears whispering from 3 times as far away as the human, but the
cat hears that from 6 times as far away as the human.
That is also the reason, why cats, but also dogs may react
frightened or aggressively to those bangs of New Year's eve's
fireworks or to thunder.
Development
At birth the external auditory canal is closed, that is why the
sense of hearing is not yet developed. Development starts with 5
days, with 2 weeks a kitten is able to discriminate the direction of
a sound. And with 4 weeks the sense of hearing is fully developed.
Why white cats may be deaf
Read the article
about deafness in cats.
|
