Why do cats hiss?
Cat hissing is a powerful message meant to get the attention
of a potential attacker ... and it works
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Cat hissing is one of the many sounds cats make when they:
- are annoyed or angry
- feel threatened (and that often means
just plain scared)
- or are on the brink of physical aggression.
The message is ... leave
me alone ... if I must defend myself ... I will.
A hissing cat is hoping to startle its enemy long enough
so it has a chance to escape ... or really frighten a potential
attacker, so it backs off completely.
If given a choice, cats would rather not engage in any type
of harmful conflict or fight.
Cats issue a series of vocal
warnings
... which other animals (and people) instinctively understand.
For each threatening cat sound you hear, the cat is one step
closer to actual physical aggression.
Vocal warnings usually begin with the impressive rolling
growl, which
is common in many animals. If growling doesn't do the trick,
the next step up is the snake-like hiss.
Researchers believe that cats use an instinctive
and effective method of self-defence called mimicry,
which has evolved over the ages and across species.
Cat hissing, sounds very much like the hiss
of a snake, which is a sound or warning that
causes alarm and fear in the animal kingdom and people.
How a cat makes the hissing
sound 
Cats leave their mouths partially open and tense their facial
muscles. With their lips pulled back and razor sharp teeth
on display, a rush of air is forced through the cat's
grooved tongue, which creates the hissing
sound.
Cat hissing is often followed by spitting,
an powerful spray of moisture thrust out of a cat's mouth
on a blast of forced air.
(Notably, spitting is an unpopular behavior in our own culture.)
To add some impact to cat hissing,
an aggressive cat may also flatten its ears against its head
One theory is this ear posture makes the hissing cat also
look like a snake.
Another is the ears are flattened to protect
them from injury, should felines actually
have no choice but to fight.
Mother Nature kicks in again
with another threatening display known as piloerection
Piloerection occurs when tiny muscles under the cat's hair cause
the hair to stand on end.
A feline will also arch its back and turn its body so it faces
sideways toward the enemy.
Both of these postures are meant to make cats appear larger
and more capable of defending themselves.
Should these defensive measures fail to scare off an attacker,
physical aggression is likely to occur.
During a cat fight, cat sounds might include a snarl
(a short, harsh growl with snapping or gnashing of teeth) and
a shriek or scream
(a reaction to pain).
Hissing can occur for many
reasons
If your pet cat is handled when it's not well or is in pain
it might express its discomfort with an angry hiss (just as
we might yelp under similar circumstances).
If you own more than one cat, a cat returning home with strange
smells, may trigger a hissing episode from a confused house
mate.
Although not proven, one cat may sense when another cat is
not well and will try to avoid being exposed to a contagious
illness by hissing.
Whether we understand the reasons or not, the message remains
the same ... keep your distance.