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- Stevie has healthy, normal eyes
- meaning he doesn't see too well.
- Misty's eyes glow red, which is
common for Blaze ferrets.
- Captain Morgan has his eye
poked out by a toddler with a fork.
- His eye doesn't hurt anymore,
but he can't see out of it at all.
- Parts of the Ferret
- Your ferret’s eyes are similar to
that of a human. On the outside, you see an "eyebrow" made
up of eight whiskers that help ferrets sense objects that might
impact the eye from above. Human eyebrows are much shorter, because
we use our lashes for eye protection, and ferrets have extremely
tiny lashes. At the corner of the eye is the edge of the nictitating
membrane (inner eyelid). Ferrets have an outer eyelid that covers up
most of the sclera (the white part of the eye), so what you see is
the iris (colored part) and the pupil. The iris and pupil are
usually so dark that it is difficult to tell the difference between
- The protective covering over the iris
and pupil is the cornea. Light goes through the clear cornea and the
lens underneath it and shines on the back of the eye, which is the
retina. Special visual receptors in the retina, called rods and
cones, transmit information to the optic nerve and to the brain.
This is how ferrets (and humans) see.
- What Does a Healthy
Eye Look Like?
- Ferret eyes should be bright and shiny
with no visible opaqueness (whitish areas) when held near light, or
using a pen light. There should be no tearing or discharge. Areas
around the eyes should be free of evidence of tearing or crusting at
the corners. The inner eyelid should not be in evidence, except at
the very corner of the eye. Eyes should also be even in size. Any
noted problems should be checked by a veterinarian.
- Eye Colors
- The iris of a ferret is usually dark
brown (for a sable ferret), burgundy (dark-eyed whites, blazes, or
pandas), or red (albinos). On rare occasions, a ferret will have
blue eyes (usually a blaze ferret). The red eyes of the albino are
not really red; they are actually clear and have no pigment at all,
so the red color you see is blood circulating. Similarly, the
burgundy or cranberry-colored eyes of the dark-eyed white only have
some pigment, so you see a combination of brown coloring and red
- Visual Stimuli
- According to noted ferret researcher
Fara Shimbo, training ferrets by using visual stimuli (such as using
hand signals to get your ferret to do tricks) is very frustrating,
because ferrets rarely prefer to pay attention to visual stimuli. In
fact, although ferrets are expert maze runners, the visible features
of the maze play no part in the ferrets’ ability to learn their
way around. Visible features do, however, influence how much time
the ferret will spend investigating that part of the maze. If you
must use a visual cue, make sure it is drastic enough to get a
ferret’s attention in the first place. A ferret will pay more
attention to complex visual stimuli. For example, ferrets will
prefer black-and-white stripes over a solid color.
- Ferret Vision: How
Well Do Ferrets See?
- At close range (one or two ferret
lengths), your ferret sees better detail than you do. Ferrets have
better visual acuity at close ranges than cats, but worse than most
rodents. However, ferrets have a "blind spot" directly in
front of their nose, so they will smell whatever is under their nose
rather than seeing it. Additionally, at farther distances, ferrets
do not see detail well at all. It is unlikely that ferrets can look
up at you and see specific details of your face; they just know you
have a face.
- It is important for ferrets
interacting with each other to be able to see at close range.
Ferrets often communicate with body language to you and to other
ferrets. The bottle-brush tail, vibrating tails, weasel war dancing,
plowing the carpet, and other visual displays are all meant to say
something to others.
- Ferrets have "binocular" or
"stereoscopic" vision. This means that ferret eyes are
placed more to the sides of their heads than humans and have much
better peripheral vision. However, the domesticated ferret has
different binocular vision than Steppe or European polecats, or even
the American Black-Footed Ferret, because domestication has changed
the eye socket placement in the skull. Although ferrets can swivel
their eyes to look at different objects, they don’t use their eyes
independently. For the most part, ferrets look forward, and turn
their heads to see things to the side, just like we do.
- Studies have shown that ferrets are
quite variable in their ability to perceive depth. Most ferrets have
little depth perception, and will happily walk off a table,
bookcase, or even a cliff with no hesitation. This may be because of
their inability to see how far down the floor really is. Ferret
safety is an issue here: make sure to ferret-proof your home in such
a way that your ferrets cannot climb up tall objects and then fall
off. On the other hand, a few ferrets, like their wild cousins, are
terribly afraid of heights and will scramble away from the edge of a
table, or be extremely uncomfortable about riding on your shoulder
unless supported by a hand.
- Seeing in the Dark: My
Ferret’s Eyes Glow!
- Ferret eyes work best at
"twilight" or at dusk and dawn. This phenomenon is
probably left over from when the ferret was a wild polecat thousands
of years ago. Polecats hunt their prey and are most active at dusk
and dawn. Ferrets do not see well in pitch dark, and have difficulty
adapting to bright light. However, their ability to see in low-light
conditions is far better than that of humans.
- Ferrets’ eyes appear to glow in the
dark. Actually, the eye does not produce light, it merely has the
ability to reflect extremely low levels of light. Similar to cats
and horses, ferrets’ eyes have a "tapetum lucidum" which
is a reflective layer at the back of the retina that shines even the
smallest amount of light back onto the rods and cones. This extra
reflection helps ferrets to have more effective vision at low light
- Ferrets’ eyes can "glow"
in different colors. For example, albino ferrets’ red eyes will
most often glow a bright pinkish green. Ferrets with burgundy or
cranberry-colored eyes or blue-eyed ferrets glow red. Most ferrets
with brown eyes glow green or yellow. On rare occasions, a ferret
will have one eye that glows green and one that glows red!
- Another reason ferrets see well in
low-light conditions is because of the shape of their pupil. Humans
have a round pupil, and ferrets have a slit pupil. Slit pupils
enhance edge detection and make objects more visible in low light.
Cats also have a slit pupil, but a cat’s pupil is slit vertically,
and a ferret’s pupil is slit horizontally. This difference is
because cats hunt prey that scurry past them horizontally, and
ferrets are attracted to objects that hop up and down vertically. A
ball bouncing up and down is much more exciting for your ferret than
for your cat! The slit pupil makes up for the nearsightedness:
although your ferret can’t make out much detail at a distance, he
can see movement quite well. So if you stand still, your ferret may
not see you across the room, but as soon as you move, he will!
- Can My Ferret See
- Research on wild polecats has shown
that polecats can distinguish red and blue, and can probably see
yellows and greens as well. However, the evolution of the
domesticated ferret has reduced the ability to see colors. Several
research studies have concluded that ferrets are only able to see
red; everything else is just shades of grey. This is not surprising,
because the ferret is less reliant on vision than other senses, and
color is not an important factor in seeing in low-light conditions.
So you don’t have to worry about picking out your ferret’s
favorite color for his hammock!
- The Life Cycle of the
- The eyes of a newborn ferret are only
25% of adult size. By the time the ferret kits open their eyes at
30-38 days, eyes are still only 60% of the adult size.
Interestingly, if ferret kits are handled daily from birth, their
eyes open earlier. By about three months, eyes have reached full
adult size. This slow development indicates that eyesight is less
important to ferrets than other senses, such as smell, touch, and
hearing. Reliance on other senses is good because many ferrets lose
their eyesight as they become senior citizens, but get along fine
- Blindness and Vision
- Blind ferrets are not uncommon.
Ferrets can lose their eyesight at an early age due to illness, or
even medications used to treat illnesses. Ferrets can also lose eyes
in accidents. Eye punctures, scratched corneas, and luxated lenses
can cause your ferret to lose sight in one or both eyes. Older
ferrets begin to lose their vision just like humans do, and they may
become totally blind toward the end of their lives. This blindness
is usually due to cataracts.
- Albino ferrets often suffer from being
cross-eyed, thus reducing their ability to see well. Additionally,
albino ferrets suffer from an abnormality that sends scrambled
signals from the eye to the brain, thus disrupting binocular vision
and the ability to process visual stimuli correctly. Even colored
ferrets can have this albino vision abnormality, because many
colored ferrets (especially cinnamons, dark-eyed whites, and pandas)
have albino genes.
- Some ferrets are born with aphakia (no
lens), microphakia (small lens), or microphthalmos (decreased eye
size). Ferret with very small eyes or eyes of different sizes may
have these congenital defects. These ferrets should not be bred.
- Despite blindness or genetic vision
problems, ferrets do not seem to have much of a problem with loss of
vision. Many people do not even notice that their ferret is blind.
Ferrets easily learn their way around their cage and house by
remembering where objects are located and the distances between
them. You may only notice your ferret is blind if you buy a new
piece of furniture or shut a door that has always been open. Then
you might notice your ferret running into the new item or bumping
the closed door. Blind ferrets in a new, unfamiliar situation will
hug the edges of walls and explore with their nose and whiskers and
soon learn their way around. In multiple-ferret households, a
sighted ferret will often pair with a blind ferret and act as the
"seeing-eye ferret" for the visually impaired one.
- Allergies and Eye
- Does your ferret have tearing, watery
eyes? A clear discharge may indicate an allergy. Ferrets have
sensitive respiratory systems, and the same things that irritate
ferret lungs can irritate ferret eyes. The most common cause of
allergy is from the litterbox. Avoid dusty clay litters, or any
litters with special added scents. Never use clumping litters. Most
ferrets have an allergic reaction to cedar shavings, and some to
pine shavings. If you must use wood shavings, stick to aspen.
Another common cause of allergy is from deodorizers that humans use
to cover up ferret odors. Sprays, rug powders, and gel-type air
fresheners can cause ferret eyes to tear as well. Make sure to use
odor neutralizers, not coverups, and avoid carpet powders
altogether. Cigarette smoke is also a culprit for allergies. Avoid
exposing your ferrets to second-hand smoke.
- Discharge from the eye (stickier than
tears, and whitish, yellow, or green) or swollen eyes may indicate
an infection. The infection may be localized to the eye, or be part
of the symptoms of an infection elsewhere in the body. Flus and
colds can cause these discharges. Your ferret may also have
conjunctivitis, infectious keratitis (pink eye), In a worst-case
scenario, pus exuding from the eyes can be a sign of distemper. Be
sure your ferret has been properly vaccinated against distemper. If
you see a pus-like discharge from your ferret’s eyes, and you have
removed all allergens, contact your veterinarian. Your ferret may
need antibiotics or special eye drops.
- Eye Injuries
- Watery eyes can also be due to foreign
objects in the eye (dust, a piece of carpet lint, or a strand of
fur, for example). In this case, your ferret may be blinking or
trying to keep one eye closed. If you see something in your ferret’s
eye, try and flush it out with a mild saline solution made for
rinsing soft contact lenses. Do not poke your finger or any other
object into the eye in an attempt to remove the item. Finally,
watery eyes can indicate a mild injury to the eye, such as a corneal
scratch from an accident while playing or a foreign object. Your
veterinarian can prescribe eye drops or ointment that can soothe the
irritation and help speed healing.
- Ferrets can sometimes experience more
serious eye injuries. These can result in cataracts and luxated
lenses (which are explained further below). Eyes can also be
punctured accidentally from protruding cage wires, a baseboard nail
that sticks out, or any other sharp object. Conscientious
ferret-proofing to make sure your home is safe is vital for your
ferret. However, accidents can happen. Ferrets can have their eyes
lacerated while playing with a cat. I own a ferret who had his eye
punctured by a toddler swinging a fork. When eyes are cut or
punctured, the fluid inside the eyeball will evacuate. In some
cases, the eye will heal, but the fluid will not "grow
back." The eye will be much smaller, and look whitish from the
scar tissue and nictitating membrane that becomes more visible. In
other cases, the eye must be removed, and your veterinarian will
stitch the eyelid shut over the socket.
- Other Eye Diseases and
- Cataracts are a common problem in
ferrets. When the lens of the eye becomes opaque, it will let some
light in, but not visual images. Cataracts are common in older
ferrets due to aging, but juvenile cataracts can occur in kits as
well. Juvenile cataracts is most often hereditary. Some eye injuries
can cause the lens to form white scar tissue, thus forming a
cataract as well. Exposure to certain drugs, or oxygen toxicity
during anesthesia can also result in cataracts.
- Another problem ferrets can experience
is a luxated lens. This happens when the lens of the eye shifts into
an abnormal position. A blow to the eye may have damaged the
ligaments holding the lens in place. The dislocated lens may become
opaque. Options are surgery to replace the lens (usually quite
expensive), eye drops to relieve pressure, or removal of the eye.
- Ferrets can also experience the growth
of other tissues in and around the eye. Pigmentary keratitis occurs
when spots of pigment are deposited in the eye, eventually leading
to blindness. The cause of these pigment deposits is unknown.
Intraocular neoplasms (tumors within the eye) have been reported in
ferrets; some of these have been carcinomas. More common are tumors
around the eye, such as mast cell tumors and sebaceous gland tumors
on the eyelids.
- Retina problems can also occur in
ferrets. Ferrets have been reported to experience glaucoma, which is
a change in the fluid pressure inside the eye. One common symptom of
glaucoma is a larger or protruding eye. The cornea may also become
opaque, and lesions of the retina occur. Retinal lesions can also be
from your ferret experiencing diseases such as canine distemper,
toxoplasmosis, and coccidia. Nutrition can also play a role in eye
health. Deficiencies in vitamin A or taurine can lead to retinal
degeneration, as can irradiation, anemia, and toxins that have been
ingested (bracken fern, for example).
- A Final Note on Eyes
- Your ferrets’ eyes may seem to be
the most expressive part of your ferret. Human beings are drawn to
the eyes of others. Remember, though, that ferrets are less
concerned about what they see and more focused on what they smell,
feel, and hear. When you gaze into those adorable eyes, also look
for signs of health problems, as the eyes are an indicator of how
your ferret feels. Hopefully, your ferrets will have bright and
shiny eyes, and show you just how happy and healthy they really are!