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- Deaf Daisy, a black-eyed marked
- Flower, with the Waardenburg
stripe, but not deaf, only hard of hearing
- Zeus, with the Waardenburg
stripe, and completely deaf
not Ignoring You -- I'm Deaf!
was once watching eight of my ferrets play in the living room, when the
trash collector outside dropped an entire Dumpster—with a terrific
bang! I jumped a foot high, and seven ferrets immediately scattered and
hid. The eighth, Bobbin, stood in the middle of the floor with a puzzled
look, as if to ask, "Hey! Where did everyone go?" That's when
I knew Bobbin was deaf, which is fairly common in ferrets.
Deafness in ferrets is usually a genetic
defect caused by Waardenburg syndrome, which results in the
underdevelopment of the hearing mechanism of the inner ear. In ferrets
with Waardenburg syndrome, deafness is genetically
linked with white markings on the face. Generally, this affects
ferrets with "blaze" markings (a white "badger
stripe" on top of the head and a white bib) and those with
"panda" markings (a white head and bib, with no mask). It's
estimated that 75 percent of badger and panda ferrets are deaf.
Waardenburg syndrome can also be present in dark-eyed whites like
Bobbin. (Albino ferrets—also called red-eyed whites—have abnormally
small hearing mechanisms in their middle and inner ear; they can be hard
of hearing but are not usually deaf.) Unfortunately, the attractive
color patterns of dark-eyed whites, badgers, and pandas make these
ferrets highly sought after, and breeders do not always test for
deafness, which can be difficult to determine.
Determining if your ferret is deaf will take
skill and observation, especially because hearing
ferrets can be unresponsive to certain sounds. However, deaf ferrets
have a couple characteristics that can help with the diagnosis: They are
easily startled if approached from behind, and they are often more vocal
than hearing ferrets. When startled, many deaf ferrets will express
surprise by screaming.
All ferrets are sensitive to movement and vibration, so if you clap your
hands or stamp your foot to determine deafness, your ferret may be
reacting to the movement of your body, or to the vibration in the air or
on the floor, rather than the sound. My favorite in-home test is to
place a vacuum cleaner in the room with the ferrets, stand where they
can't see you, and then plug in the vacuum cleaner to turn it on. In
most cases, the hearing ferrets will dash away (or attack the vacuum),
and the deaf ferrets will wonder why everyone else left!
There are also scientific tests for deafness. The hearing test known as
the brain-stem auditory evoked response (BAER) or brain-stem auditory
evoked potential (BAEP) is potentially useful in determining deafness in
ferrets. This is a test performed routinely by reputable breeders of
Dalmatian dogs to determine the extent of hearing loss or deafness in
their breeding stock. The procedure is not painful, and no sedation is
necessary. Most veterinary colleges of medicine at universities have the
testing equipment, as do some individual clinics.
The test detects electrical activity in the inner ear and brain in much
the same way that an antenna detects radio signals or an EKG detects the
heart's electrical activity. Electrodes are placed around the ear and on
the head, and send pictures of "hearing" to a computer. The
series of peaks on the waveform correspond to the response of the inner
ear and the brain. The response from a deaf ear is a flat line.
Deaf ferrets pose potential behavioral and
training problems. Deaf mother ferrets may be more likely to injure
their babies, because they can't hear them cry. Deaf ferrets also seem
to be more prone to biting, given that they are easily startled and will
immediately try to defend themselves. Additionally, they are more
difficult to train, because they do not respond to your voice commands.
Because of the challenges posed by deaf ferrets, particularly for
beginner owners, responsible breeders should be more careful about
breeding for color patterns not associated with hearing problems.
Deaf ferrets do respond to lots of love and treats, and can even be
trained to respond to hand signals. I have had several deaf ferrets, and
they don't seem to mind at all that they can't hear. Misty, my deaf
blaze, is the alpha ferret in my household—over 10 other ferrets! She
loves to play, bounce, hide, eat, snooze, and snuggle with her hearing
Dutch eye doctor P. J. Waardenburg was the
first to notice a link between hearing problems and
pigmentation. Waardenburg syndrome shows up in humans as well as
in ferrets, dogs, cats, mice, and other animals. Humans with
eyes of different colors often have hearing problems. People
with Waardenburg syndrome may also have a white forelock of
hair, and their hair may turn gray prematurely.
Deafness is far more common in white cats than in those with
other coat colors. According to the ASPCA Complete Guide to
Cats, 17 to 20 percent of white cats with nonblue eyes are
deaf; 40 percent of "odd-eyed" white cats with one
blue eye are deaf; and 65 to 85 percent of blue-eyed white cats